Image prediction method, device, system, apparatus, and storage medium

Abstract

Image prediction methods, devices, and systems, devices, and storage media are provided. The method includes a step of obtaining a partition mode of a current node (401). The current node is an image block in a coding tree unit of a current image. The method also includes a step of determining whether the current node satisfies a first condition based on the partition mode of the current node and a size of the current node (402). If it is determined that the current node satisfies the first condition, a step of performing intra prediction on all coding blocks belonging to the current node and a step of obtaining predictors for all coding blocks belonging to the current node (408).

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 201910016466.3, entitled "VIDEO DECODING METHOD AND VIDEO DECODER," filed with the Patent Office of the State Intellectual Property Administration of the People's Republic of China on January 8, 2019; to Chinese Patent Application No. 201910173454.1, entitled "VIDEO ENCODER, VIDEO DECODER, AND CORRESPONDING METHODS," filed with the Patent Office of the People's Republic of China on March 7, 2019; to Chinese Patent Application No. 201910219440.9, entitled "VIDEO ENCODER, VIDEO DECODER, AND CORRESPONDING MEHODS," filed with the Patent Office of the People's Republic of China on March 21, 2019; and to Chinese Patent Application No. 201910219440.9, entitled "VIDEO ENCODER, VIDEO DECODER, AND CORRESPONDING MEHODS," filed with the Patent Office of the People's Republic of China on July 30, 2019. This application claims priority to Chinese Patent Application No. 201910696741.0, entitled "A Method and System for Producing a High-Performance Data Sheet, a Printed Document, and a Storage Medium," which are incorporated herein by reference in their entireties.

[0002] TECHNICAL FIELD Embodiments of the present application relate to the field of video coding technology, and in particular to image prediction methods, devices, systems, apparatuses, and storage media. [Background technology]

[0003] Digital video capabilities can be incorporated into a wide variety of devices, including digital televisions, digital live broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-readers, digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio telephones (also known as "smartphones"), video conferencing equipment, video streaming devices, etc. Digital video devices implement video compression technologies, such as those described in standards defined by MPEG-2, MPEG-4, ITU H.263, and ITU H.264 / MPEG-4 Part 10 AVC (advanced video coding), video coding standard H.265 / High Efficiency Video Coding (HEVC) standards, and extensions to such standards. Implementing video compression technologies enables video devices to more efficiently transmit, receive, encode, decode, and / or store digital video information.

[0004] With the development of information technology, video services such as high-definition television, web conferencing, IPTV, and 3D television are rapidly developing. Video signals have become the most important way of obtaining information in people's daily lives due to their intuitiveness and high efficiency. Because video signals contain a large amount of data, they occupy a large transmission bandwidth and storage space. To effectively transmit and store video signals, they need to be compressed and encoded. Video compression technology has become an increasingly essential key technology in the field of video applications.

[0005] The encoding process mainly includes the following steps: intra prediction, inter prediction, transform, quantization, entropy encode, in-loop filtering (mainly deblocking filtering), etc. After dividing an image into coding blocks, intra prediction or inter prediction is performed. Next, after obtaining a residual, transform and quantization are performed. Finally, entropy encoding is performed to output a bitstream. In this specification, a coding block is an array with a size of M×N pixels (where M may or may not be equal to N). Furthermore, the value of a pixel at each pixel position is known. Video decoding is the reverse process of video encoding. For example, entropy decoding, dequantization, and inverse transform are first performed to obtain residual information; and whether intra prediction or inter prediction is performed for the current block is determined by decoding the bitstream. When intra-coding is performed, a prediction block is constructed based on pixel values ​​of pixels in a reconstructed area around the current image using an intra-prediction method. When inter-coding is performed, motion information needs to be obtained by analysis, a reference block is determined in the reconstructed image based on the motion information obtained by analysis, and the pixel values ​​of pixels in the reference block are used as the prediction block (such a process is called motion compensation (MC)). To obtain the reconstructed information, the prediction block and residual information are added, and a filtering operation is performed.

[0006] Currently, two child nodes, each having a size of 4×M (or M×4), are generated by dividing a node having a size of 8×M (or M×8) through vertical binary tree division (or horizontal binary tree division). Similarly, two child nodes, each having a size of 4×M (or M×4) and one child node having a size of 8×M (or N×8), are generated by dividing a node having a size of 16×M (or M×16) through vertical ternary tree division (or horizontal ternary tree division). In the YUV4:2:0 data format, the resolution of the chroma components is half that of the luma component. In other words, one 4×M node includes one 4×M luma block and two 2×(M / 2) chroma blocks. Therefore, small chroma blocks having sizes such as 2×2, 2×4, or 4×2 can be generated by dividing the current node through a preset division mode. It is relatively complicated for a hardware decoder to process small chroma blocks. The complexity is particularly reflected in three aspects:

[0007] (1) Intra prediction: To increase processing speed, hardware is generally designed to process 16 pixels at a time during intra prediction. However, small chroma blocks, such as 2x2, 2x4, or 4x2, contain fewer than 16 pixels. As a result, the processing performance of intra prediction decreases.

[0008] (2) Coefficient Coding: In HEVC, transform coefficient coding is performed based on a coefficient group (CG) containing 16 coefficients. However, small chroma blocks, such as 2x2, 2x4, or 4x2, contain four or eight transform coefficients. As a result, to support coefficient coding for these small blocks, additional coefficient groups containing four or eight coefficients are required, which increases the implementation complexity.

[0009] (3) Inter-prediction: Inter-prediction for small chroma blocks has a relatively high requirement on data bandwidth, which affects the decoding speed. Summary of the Invention

[0010] The present application provides an image prediction method, apparatus, system, device, and storage medium for improving the processing performance of image prediction and increasing the coding processing speed.

[0011] A first aspect of the present application provides an image prediction method, including the steps of: obtaining a partition mode of a current node; determining whether an image block having a preset size is obtained by partitioning the current node using the partition mode of the current node, where the image block includes a luma block or a chroma block; and performing intra prediction or inter prediction on all coding blocks covered by the current node when it is determined that an image block having the preset size is obtained by partitioning the current node using the partition mode of the current node.

[0012] Optionally, the image block having a preset size may be a luma block having a size less than a threshold, which may be a number of luma samples such as 128, 64, or 32, or a number of chroma samples such as 32, 16, or 8. The size of the current node may be greater than or equal to the threshold.

[0013] Optionally, the step of performing intra prediction may perform the prediction by using a common intra prediction mode (intra mode) or an IBC (intra block copy) mode.

[0014] Optionally, all coding blocks covered by the current node are all coding blocks located in the region corresponding to the current node. Alternatively, a coding block may be a coding unit.

[0015] Optionally, if the slice type in which the current node is located is of intra type, intra prediction is performed for all coding blocks covered by the current node instead of inter prediction.

[0016] The advantageous effects of the embodiments of the present application are as follows: In the present application, it is considered that luma blocks or chroma blocks having a preset size are obtained by dividing an image block corresponding to a current node. When the above case exists, the encoder or decoder performs intra prediction or inter prediction on all coding blocks obtained by dividing or not dividing the current node serving as the root node, thereby performing parallel processing of luma blocks or chroma blocks having a preset size. This improves the processing performance of image prediction and further improves coding performance.

[0017] Optionally, the following two cases relate to image blocks having preset sizes: luma blocks having a first preset size and chroma blocks having a second preset size. The step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes: determining whether a luma block having the first preset size can be obtained by dividing the current node in a partition mode; performing intra prediction on all coding blocks covered by the current node if it is determined that a luma block having the first preset size can be obtained by dividing the current node in the partition mode; or performing intra prediction or inter prediction on all coding blocks covered by the current node if it is determined that a luma block having the first preset size cannot be obtained by dividing the current node in the partition mode.

[0018] Optionally, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node when it is determined that a luma block having a first predetermined size is not obtained by dividing the current node in the division mode may include: analyzing a prediction mode status flag of the current node when it is determined that a luma block having the first predetermined size is not obtained by dividing the current node in the division mode; performing inter prediction on all coding blocks covered by the current node when the value of the prediction mode status flag is a first value; or performing intra prediction on all coding blocks covered by the current node when the value of the prediction mode status flag is a second value.

[0019] With regard to the first aspect, in a first possible implementation example of the first aspect, the image block having the preset size includes a luma block having a first preset size, and the step of determining whether the image block having the preset size can be obtained by dividing the current node in a division mode includes a step of determining whether the luma block having the first preset size can be obtained by dividing the current node in a division mode based on the size of the current node and the division mode of the current node.

[0020] Optionally, the luma block having the first preset size may be a luma block having a pixel size of 4x4 or 8x8, or a luma block having an area of ​​16 pixels or 32 pixels.

[0021] Optionally, when the luma block having the first preset size is a luma block having a pixel size of 4x4 or an area of ​​16 pixels, determining whether a luma block having the first preset size is obtained by dividing the current node in a division mode based on the size of the current node and the division mode of the current node may be performed based on one of the following conditions: The number of samples in the luma block of the current node is 64, and the partitioning mode is quadtree partitioning; The number of samples in the luma block of the current node is 64 and the partitioning mode is ternary tree partitioning; or The number of samples in the luma block of the current node is 32, and the partitioning mode is binary tree partitioning.

[0022] With respect to a first possible implementation example of the first aspect, optionally, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node when it is determined that an image block having a predetermined size will be obtained by dividing the current node in the division mode of the current node includes the step of performing intra prediction on all coding blocks covered by the current node when it is determined that a luma block having a first predetermined size will be obtained by dividing the current node in the division mode.

[0023] With respect to a first possible implementation example of the first aspect, optionally, when it is determined that a luma block having a first preset size is not obtained by dividing the current node in the division mode, the method further includes a step of determining whether a chroma block having a second preset size is obtained by dividing the current node in the division mode; and a step of performing intra prediction or inter prediction on all coding blocks covered by the current node when it is determined that a chroma block having the second preset size is obtained by dividing the current node in the division mode.

[0024] In conclusion, in the first embodiment described above, it is determined that intra prediction or inter prediction is performed on all coding blocks obtained by dividing or not dividing the current node functioning as the root node, so that parallel processing can be performed on luma blocks or chroma blocks having a preset size, thereby improving the processing performance of image prediction and further improving coding performance.

[0025] Optionally, the luma block having the first preset size may be a 4x4 luma block or a luma block having an area of ​​16 pixels. When the luma block having the first preset size is a 4x4 luma block, the chroma block having the second preset size may be a chroma block having a pixel size of 2x4 or 4x2, or a chroma block having an area of ​​8 pixels, excluding a chroma block having a pixel size of 2x2 or an area of ​​4 pixels.

[0026] Optionally, the luma block having the first preset size may be a 4x4 luma block or a luma block having an area of ​​16 pixels. When the luma block having the first preset size is a 4x4 luma block, the chroma block having the second preset size may be a luma block having a pixel size of 4x8 or 8x4, or a luma block having an area of ​​32 pixels, excluding the luma block having a pixel size of 4x4 or an area of ​​16 pixels.

[0027] Optionally, when the chroma block having the second preset size is a chroma block having a pixel size of 2×4 or 4×2 or a chroma block having an area of ​​8 pixels, or a chroma block having a pixel size of 4×8 or 8×4 or a luma block having an area of ​​32 pixels, determining whether a chroma block having the second preset size is obtained by dividing the current node in the division mode may be performed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (2) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0028] With respect to the first aspect, in a second possible implementation example of the first aspect, the image block having the preset size includes a chroma block having a second preset size, and the step of determining whether the image block having the preset size can be obtained by splitting the current node in the split mode includes the step of determining whether the chroma block having the second preset size can be obtained by splitting the current node in the split mode based on the size of the current node and the split mode of the current node.

[0029] Optionally, the chroma block having the second preset size may be a chroma block having a pixel size of 2x2, 2x4, or 4x2, or a chroma block having an area of ​​4 pixels or 8 pixels.

[0030] Optionally, the step of determining whether a chroma block having a second preset size is obtained by splitting the current node in a split mode based on the size of the current node and the split mode of the current node may include the step of determining whether a luma block having a third preset size is obtained by splitting the current node in a split mode based on the size of the current node and the split mode of the current node.

[0031] Optionally, the luma block having a third preset size may be a luma block having a pixel size of 4x4, 4x8, or 8x4, or a luma block having an area of ​​16 pixels or 32 pixels.

[0032] Optionally, determining whether a chroma block having a second preset size is obtained by splitting the current node in the split mode may be performed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is quadtree partitioning; (2) The number of samples in the luma block of the current node is 64, and the partitioning mode is ternary tree partitioning; (3) The number of samples in the luma block of the current node is 32, and the partitioning mode is binary tree partitioning; (4) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (5) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0033] Optionally, the chroma blocks having the second preset size may be chroma blocks having a pixel size of 2x4 or 4x2, or chroma blocks having an area of ​​8 pixels, excluding chroma blocks having a pixel size of 2x2 or chroma blocks having an area of ​​4 pixels. Similarly, the luma blocks having the third preset size may be luma blocks having a pixel size of 4x8 or 8x4, or luma blocks having an area of ​​32 pixels, excluding luma blocks having a pixel size of 4x4 or luma blocks having an area of ​​16 pixels. Correspondingly, the step of determining whether a chroma block having the second preset size is obtained by dividing the current node in the division mode may be performed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (2) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0034] With respect to the first or second embodiment, when it is determined that a chroma block having a second preset size is obtained by splitting the current node in the split mode, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes the steps of analyzing a prediction mode status flag of the current node; and performing inter prediction on all coding blocks covered by the current node if the value of the prediction mode status flag is a first value; or performing intra prediction on all coding blocks covered by the current node if the value of the prediction mode status flag is a second value. This embodiment is used in a video decoder. The prediction modes used for all coding blocks obtained by splitting or not splitting the current node serving as the root node are determined by analyzing the prediction mode status flag from the bitstream. Compared to conventional techniques, the analysis only needs to be performed once, thereby increasing the processing speed of video decoding.

[0035] Optionally, the slice type in which the current node is located is not of the Intra type.

[0036] With respect to the first or second embodiment, when it is determined that a chroma block having a second preset size is obtained by splitting the current node in the split mode, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes: performing inter prediction on all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is inter prediction; or performing intra prediction on all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is intra prediction. Optionally, the any coding block is the first coding block of all coding blocks covered by the current node in decoding order. This embodiment is used in a video decoder. The prediction mode used for any coding block of the current node is analyzed from the bitstream, and the prediction mode obtained by the analysis is used to predict all coding blocks obtained by splitting or not splitting the current node serving as the root node. Compared to conventional techniques, the analysis is performed only once, thereby increasing the processing speed of video decoding.

[0037] Regarding the second embodiment, optionally, when it is determined that chroma blocks having a second preset size are obtained by dividing the current node in the partition mode, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes the steps of: determining whether luma blocks having a first preset size are obtained by dividing the current node in the partition mode; and performing intra prediction on all coding blocks covered by the current node when it is determined that luma blocks having the first preset size are obtained by dividing the current node in the partition mode. In this embodiment, since it is determined that intra prediction is performed on all coding blocks obtained by dividing or not dividing the current node functioning as the root node, parallel processing can be performed on luma blocks having the first preset size and chroma blocks having the second preset size. This improves the processing performance of image prediction and further improves coding performance.

[0038] Optionally, when it is determined that a luma block having a first preset size is not obtained by splitting the current node in the split mode, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes the steps of analyzing a prediction mode status flag of the current node; and performing inter prediction on all coding blocks covered by the current node if the value of the prediction mode status flag is a first value; or performing intra prediction on all coding blocks covered by the current node if the value of the prediction mode status flag is a second value. This embodiment is used in a video decoder. The prediction modes used for all coding blocks obtained by splitting or not splitting the current node serving as a root node are determined by analyzing the prediction mode status flag from the bitstream. Compared with conventional techniques, the analysis only needs to be performed once, thereby increasing the processing speed of video decoding.

[0039] Optionally, when it is determined that a luma block having the first preset size is not obtained by splitting the current node in the split mode, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes: performing inter prediction on all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is inter prediction; or performing intra prediction on all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is intra prediction. This embodiment is used in a video decoder. The prediction mode used for any coding block of the current node is analyzed from the bitstream, and the prediction mode obtained by the analysis is used to predict all coding blocks obtained by splitting or not splitting the current node serving as the root node. Compared to conventional techniques, the analysis only needs to be performed once, thereby increasing the processing speed of video decoding.

[0040] Optionally, the given coding block is the first coding block of all coding blocks covered by the current node in decoding order.

[0041] Regarding the first aspect or any one of the possible implementation forms of the first aspect, in a third possible implementation form of the first aspect, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes: in a partition mode, dividing a luma block included in the current node to obtain a luma block obtained by the partition, and performing intra prediction on the luma block obtained by the partition, and using a chroma block included in the current node as a chroma coding block to perform intra prediction on the chroma coding block; or, in a partition mode, dividing a luma block included in the current node to obtain a luma block obtained by the partition, and performing inter prediction on the luma block obtained by the partition, and dividing a chroma block included in the current node in the partition mode to obtain a chroma block obtained by the partition, and performing inter prediction on the chroma block obtained by the partition. In this implementation, regardless of whether intra prediction or inter prediction is performed on all coding blocks covered by the current node, the luma block of the current node is always partitioned, and in the inter prediction mode, the chroma block of the current node may be partitioned, but in the intra prediction mode, the chroma block of the current node is not partitioned. In this embodiment, a chroma block having a second predetermined size on which intra prediction is performed is not generated, thereby avoiding cases where intra prediction is performed on small chroma blocks, thereby increasing the processing speed of video coding.

[0042] With respect to the first aspect or any one of the possible implementation forms of the first aspect, in a fourth possible implementation form of the first aspect, the step of performing intra prediction or inter prediction on all coding blocks covered by the current node includes: in a partition mode, dividing a luma block included in the current node to obtain a luma block obtained by the partition, performing intra prediction on the luma block obtained by the partition, and using a chroma block included in the current node as a chroma coding block to perform intra prediction on the chroma coding block; or in a partition mode, dividing a luma block included in the current node to obtain a luma block obtained by the partition, performing inter prediction on the luma block obtained by the partition, and using a chroma block included in the current node as a chroma coding block to perform inter prediction on the chroma coding block. In this implementation, regardless of whether intra prediction or inter prediction is performed on all coding blocks covered by the current node, the chroma blocks of the current node are not divided, and the luma blocks are divided in the luma block partition mode. In this embodiment, a chroma block having a second predetermined size on which intra prediction is performed is not generated, thereby avoiding cases where intra prediction is performed on small chroma blocks, thereby increasing the processing speed of video coding.

[0043] Regarding the first aspect or any one of the possible implementation forms of the first aspect, in a fifth possible implementation form of the first aspect, if inter prediction is performed on all coding blocks covered by the current node, the step of performing inter prediction on all coding blocks covered by the current node includes: The method includes: dividing the current node in a division mode of the current node to obtain a child node of the current node; determining a division mode that is not permitted for the child node of the current node based on a size of the child node of the current node; determining a block division policy for the child node of the current node based on the division mode that is not permitted for the child node of the current node; obtaining a coding block corresponding to the child node of the current node according to the block division policy of the child node of the current node; and performing inter prediction on the corresponding coding block. In this embodiment, in the case of inter prediction, a luma block having a first predetermined size is not generated.

[0044] A child node can be obtained by dividing the current node once, or can be obtained by dividing the current node N times, where N is an integer greater than 1.

[0045] The splitting policy may include no splitting, one splitting, or N splitting, where N is an integer greater than one.

[0046] A second aspect of the present application provides an image prediction device, the device comprising: an acquisition module configured to acquire a partition mode of the current node; a determining module configured to determine whether an image block having a preset size is obtained by dividing a current node in a division mode, where the image block includes a luma block or a chroma block; An execution module configured to perform intra prediction or inter prediction on all coding blocks covered by the current node when it is determined that an image block having a predetermined size is obtained by dividing the current node in the division mode;

[0047] A third aspect of the present application provides a video encoding apparatus including a processor and a memory configured to store processor executable instructions, the processor performing a method according to the first aspect of the present application.

[0048] A fourth aspect of the present application provides a video decoding apparatus including a processor and a memory configured to store processor executable instructions, the processor performing a method according to the first aspect of the present application.

[0049] A fifth aspect of the present application provides an image prediction system including a video acquisition device, a video encoding device according to the third aspect of the present application, a video decoding device according to the fourth aspect of the present application, and a display device, wherein the video encoding device is connected to both the video acquisition device and the video decoding device, and the video decoding device is connected to the display device.

[0050] A sixth aspect of the present application provides a computer-readable storage medium storing a computer program, the computer program being executed by a processor to perform the method according to the first aspect of the present application.

[0051] A seventh aspect of the present application provides an image prediction method, the method comprising: The method includes: obtaining a partition mode of a current node, where the current node is an image block in a coding tree unit of a current image; determining whether the current node satisfies a first condition based on the partition mode of the current node and the size of the current node; and performing intra prediction on all coding blocks belonging to the current node to obtain predictors of all coding blocks belonging to the current node if it is determined that the current node satisfies the first condition.

[0052] The size of the current node is determined based on the size of the coding tree node that corresponds to the current node and the partitioning mode used to obtain the current node.

[0053] The type of the slice in which the current node is located is type B or type P. It should be understood that if the type of the slice in which the current node is located is type I, by default, intra prediction needs to be performed on all coding blocks covered by the current node.

[0054] Optionally, a step of determining whether the current node satisfies a first condition may be performed if the size of the current node is less than or equal to a preset size upper limit based on the split mode of the current node and the size of the current node. The preset size upper limit may be 256, 128, or 64.

[0055] The first condition may include: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is quadtree partitioning; (2) The number of samples in the luma block of the current node is 64, and the partitioning mode is ternary tree partitioning; or (3) The number of samples in the luma block of the current node is 32, and the partitioning mode is binary tree partitioning.

[0056] With regard to the seventh aspect, in a first possible implementation example of the seventh aspect, when it is determined that the current node does not satisfy the first condition, the method further includes the steps of: determining whether the current node satisfies a second condition based on the partitioning mode of the current node and the size of the current node; and when it is determined that the current node satisfies the second condition, performing prediction on all coding blocks belonging to the current node using the same prediction mode to obtain predictors for all coding blocks belonging to the current node; wherein the prediction mode is intra prediction or inter prediction.

[0057] The step of determining whether the current node satisfies the second condition based on the split mode of the current node and the size of the current node may include the step of determining whether the current node satisfies the second condition based on the split mode of the current node, the size of the current node, and a current Chroma format.

[0058] The second condition may include: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; (2) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning; (3) The number of samples in the luma block of the current node is 64, the partitioning mode is binary tree partitioning, and the chroma format is 4:2:0; (4) The number of samples in the luma block of the current node is 128, the partitioning mode is ternary tree partitioning, and the chroma format is 4:2:0; or (5) The chroma block width of the child node of the current node is 2.

[0059] With respect to the first possible implementation example of the seventh aspect, in a second possible implementation example of the seventh aspect, the step of performing prediction for all coding blocks belonging to the current node using the same prediction mode includes the steps of analyzing a prediction mode status flag of the current node; and performing inter prediction for all coding blocks belonging to the current node if the value of the prediction mode status flag is a first value; or performing intra prediction for all coding blocks belonging to the current node if the value of the prediction mode status flag is a second value.

[0060] The prediction mode status flag may be a syntax element that is parsed during block division, i.e., during division of a coding tree. When the syntax element is parsed, the coding unit prediction mode status flag (cu_pred_mode) of the coding unit in the coverage area of ​​the current node may not be parsed, and the value of the coding unit prediction mode status flag is a default value corresponding to the value of the prediction mode status flag.

[0061] With respect to the first or second possible implementation example of the seventh aspect, in a third possible implementation example of the seventh aspect, the step of performing inter prediction on all coding blocks belonging to the current node includes the steps of: dividing the current node using a division mode of the current node to obtain child nodes of the current node; determining a division mode that is not permitted for the child nodes of the current node based on the size of the child nodes of the current node; determining a block division policy for the child nodes of the current node based on the division mode that is not permitted for the child nodes of the current node; and obtaining coding blocks corresponding to the child nodes of the current node according to the block division policy of the child nodes of the current node, and performing inter prediction on the corresponding coding blocks.

[0062] If a child node is restricted to perform only inter prediction and the number of luma samples of the child node is 32 (i.e., the product of the node's width and height is 32), binary tree partitioning (including horizontal binary tree partitioning or vertical binary tree partitioning) is not allowed for the child node. If a child node is restricted to perform only inter prediction and the number of luma samples of the child node is 64 (i.e., the product of the node's width and height is 64), ternary tree partitioning (including horizontal ternary tree partitioning or vertical ternary tree partitioning) is not allowed for the child node. This determination method is applicable to both YUV4:2:0 and YUV4:2:2 video data formats.

[0063] For example, if the size of the current node is 8x8 and two 8x4 (or 4x8) nodes are generated by horizontal binary tree splitting (or vertical binary tree splitting), further dividing the 8x4 (or 4x8) node generates a 4x4 block. In this case, vertical binary tree splitting (or horizontal binary tree splitting) is not allowed for the 8x4 (or 4x8) node, or further division of the 8x4 (or 4x8) node is not allowed. As another example, if the number of samples in the luma block of the current node is 128 and the partitioning mode is horizontal ternary tree splitting or vertical ternary tree splitting, the number of samples in the luma block may be determined to be 64. However, if horizontal ternary tree splitting or vertical ternary tree splitting of a child node is used for a luma node with a sample quantity of 64, a 4x4 luma block is obtained. Therefore, when restricted to performing only inter prediction, horizontal or vertical ternary tree division is not allowed for a node with a sample quantity of 64, or further division of a node with a sample quantity of 64 is not allowed.

[0064] With respect to the seventh aspect or any one of the aforementioned possible implementations of the seventh aspect, in a fourth possible implementation of the seventh aspect, the step of performing intra prediction on all coding blocks belonging to the current node includes, in a division mode, dividing a luma block included in the current node to obtain a luma block obtained by the division, and performing intra prediction on the luma block obtained by the division; and using a chroma block included in the current node as a chroma coding block, and performing intra prediction on the chroma coding block.

[0065] An eighth aspect of the present application provides an image prediction method, the method including: obtaining a partition mode of a current node, where the current node is an image block in a coding tree unit of a current image; determining whether the current node satisfies a preset condition based on the partition mode of the current node and a size of the current node; and if it is determined that the current node satisfies the preset condition, performing prediction on all coding blocks belonging to the current node using the same prediction mode to obtain predictors for all coding blocks belonging to the current node, where the prediction mode is intra prediction or inter prediction.

[0066] The size of the current node may be determined based on the size of the coding tree node that corresponds to the current node and the partitioning mode used to obtain the current node.

[0067] The step of determining whether the current node satisfies the preset condition based on the split mode of the current node and the size of the current node may include the step of determining whether the current node satisfies the preset condition based on the split mode of the current node, the size of the current node, and the current chroma format.

[0068] The preset conditions may include: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (2) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0069] With regard to the eighth aspect, in a first possible implementation example of the eighth aspect, the step of performing prediction for all coding blocks belonging to the current node using the same prediction mode includes the steps of analyzing a prediction mode status flag of the current node; and performing inter prediction for all coding blocks belonging to the current node if the value of the prediction mode status flag is a first value; or performing intra prediction for all coding blocks belonging to the current node if the value of the prediction mode status flag is a second value.

[0070] With respect to the eighth aspect or the first possible implementation example of the eighth aspect, in a second possible implementation example of the eighth aspect, the step of performing inter prediction on all coding blocks belonging to the current node includes the steps of: dividing the current node using a division mode of the current node to obtain child nodes of the current node; determining division modes that are not permitted for the child nodes of the current node based on the size of the child nodes of the current node; determining a block division policy for the child nodes of the current node based on the division modes that are not permitted for the child nodes of the current node; and obtaining coding blocks corresponding to the child nodes of the current node according to the block division policy of the child nodes of the current node, and performing inter prediction on the corresponding coding blocks.

[0071] If a child node is restricted to perform only inter prediction and the number of luma samples of the child node is 32 (i.e., the product of the node's width and height is 32), binary tree partitioning (including horizontal binary tree partitioning or vertical binary tree partitioning) is not allowed for the child node. If a child node is restricted to perform only inter prediction and the number of luma samples of the child node is 64 (i.e., the product of the node's width and height is 64), ternary tree partitioning (including horizontal ternary tree partitioning or vertical ternary tree partitioning) is not allowed for the child node. This determination method is applicable to both YUV4:2:0 and YUV4:2:2 video data formats.

[0072] For example, if the size of the current node is 8x8 and two 8x4 (or 4x8) nodes are generated by horizontal binary tree splitting (or vertical binary tree splitting), further dividing the 8x4 (or 4x8) node generates a 4x4 block. In this case, vertical binary tree splitting (or horizontal binary tree splitting) is not allowed for the 8x4 (or 4x8) node, or further division of the 8x4 (or 4x8) node is not allowed. As another example, if the number of samples in the luma block of the current node is 128 and the partitioning mode is horizontal ternary tree splitting or vertical ternary tree splitting, the number of samples in the luma block may be determined to be 64. However, if horizontal ternary tree splitting or vertical ternary tree splitting of the child node is used for a luma node with a sample quantity of 64, a 4x4 luma block is obtained. Therefore, when restricted to performing only inter prediction, horizontal or vertical ternary tree division is not allowed for a node with a sample quantity of 64, or further division of a node with a sample quantity of 64 is not allowed.

[0073] A ninth aspect of the present application provides an image prediction method, including: determining a partition mode that is not allowed for a current node based on a size of the current node and a prediction mode of the current node, where the current node is an image block in a coding tree unit of a current image; determining a block partition policy for the current node based on the partition mode that is not allowed for the current node; and obtaining a coding block corresponding to the current node according to the block partition policy of the current node, and performing inter prediction on the corresponding coding block.

[0074] The size of the current node may be determined based on the size of the coding tree node that corresponds to the current node and the partitioning mode used to obtain the current node.

[0075] With regard to the ninth aspect, in a first possible implementation example of the ninth aspect, the step of determining a partitioning mode that is not permitted for the current node based on the size of the current node and the prediction mode of the current node includes the steps of: determining whether only inter prediction mode is used for predicting all coding blocks belonging to the current node, and determining whether the number of samples of the luma block of the current node is 32; and determining that binary tree partitioning is a partitioning mode that is not permitted for the current node if it is determined that only inter prediction mode is used for predicting all coding blocks belonging to the current node and the number of samples of the luma block of the current node is 32.

[0076] With respect to the ninth aspect or the first possible implementation example of the ninth aspect, in a second possible implementation example of the ninth aspect, the step of determining a partitioning mode that is not allowed for the current node based on the size of the current node and the prediction mode of the current node includes the steps of: determining whether only inter prediction mode is used for predicting all coding blocks belonging to the current node, and determining whether the sample amount of the luma block of the current node is 64; and determining that ternary tree partitioning is a partitioning mode that is not allowed for the current node if it is determined that only inter prediction mode is used for predicting all coding blocks belonging to the current node and the sample amount of the luma block of the current node is 64.

[0077] A tenth aspect of the present application provides an image prediction device, the device comprising: an acquisition module configured to acquire a partition mode of a current node, the current node being an image block in a coding tree unit of a current image; a determining module configured to determine whether the current node satisfies a first condition based on a partitioning mode of the current node and a size of the current node; an execution module configured, when it is determined that the current node satisfies a first condition, to perform intra prediction on all coding blocks belonging to the current node to obtain predictors for all coding blocks belonging to the current node;

[0078] Regarding the tenth aspect, in a first possible implementation of the tenth aspect, The determination module is further configured to, when it is determined that the current node does not satisfy the first condition, determine whether the current node satisfies a second condition based on a partition mode of the current node and a size of the current node; The execution module is further configured, when it is determined that the current node satisfies the second condition, to perform prediction on all coding blocks belonging to the current node using the same prediction mode to obtain predictors for all coding blocks belonging to the current node, where the prediction mode is intra prediction or inter prediction.

[0079] The determination module may be configured to determine whether the current node satisfies a second condition based on the split mode of the current node, the size of the current node, and the current chroma format.

[0080] Regarding the first possible implementation example of the tenth aspect, in a second possible implementation example of the tenth aspect, the execution module Parsing the prediction mode status flag of the current node; and The node is configured to: perform inter prediction for all coding blocks belonging to the current node when the value of the prediction mode status flag is a first value; or perform intra prediction for all coding blocks belonging to the current node when the value of the prediction mode status flag is a second value.

[0081] With respect to the first or second possible implementation of the tenth aspect, in a third possible implementation of the tenth aspect, the execution module Splitting the current node with the split mode of the current node to get the child nodes of the current node; determining disallowed splitting modes for the child nodes of the current node based on the size of the child nodes of the current node; Determining a block partitioning policy for the child nodes of the current node based on the partitioning modes that are not permitted for the child nodes of the current node; and The coding block division policy is configured to obtain a coding block corresponding to a child node of the current node according to a block division policy of the child node of the current node, and perform inter prediction on the corresponding coding block.

[0082] With respect to the tenth aspect or any one of the possible implementation forms of the tenth aspect, in a fourth possible implementation form of the tenth aspect, the execution module is configured, in a division mode, to divide a luma block included in the current node to obtain a luma block obtained by the division, and perform intra prediction on the luma block obtained by the division; and to use a chroma block included in the current node as a chroma coding block, and perform intra prediction on the chroma coding block.

[0083] An eleventh aspect of the present application provides an image prediction device, including: an acquisition module configured to acquire a partition mode of a current node, where the current node is an image block in a coding tree unit of a current image; a determination module configured to determine whether the current node satisfies a preset condition based on the partition mode of the current node and a size of the current node; and an execution module configured to perform prediction on all coding blocks belonging to the current node using the same prediction mode when it is determined that the current node satisfies the preset condition, to acquire predictors for all coding blocks belonging to the current node, where the prediction mode is intra prediction or inter prediction.

[0084] The determination module may be configured to determine whether the current node satisfies a preset condition based on the division mode of the current node, the size of the current node, and the current chroma format.

[0085] Regarding the eleventh aspect, in a first possible implementation example of the eleventh aspect, the execution module analyzing the prediction mode status flag of the current node; and The node is configured to: perform inter prediction for all coding blocks belonging to the current node when the value of the prediction mode status flag is a first value; or perform intra prediction for all coding blocks belonging to the current node when the value of the prediction mode status flag is a second value.

[0086] With respect to the 11th aspect or the first possible implementation example of the 11th aspect, in a second possible implementation example of the 11th aspect, the execution module is configured to: divide the current node in a division mode of the current node to obtain a child node of the current node; determine a division mode that is not permitted for the child node of the current node based on a size of the child node of the current node; determine a block division policy for the child node of the current node based on the division mode that is not permitted for the child node of the current node; and obtain a coding block corresponding to the child node of the current node according to the block division policy of the child node of the current node, and perform inter prediction on the corresponding coding block.

[0087] A twelfth aspect of the present application provides an image prediction device, including: a determination unit configured to determine a partition mode that is not allowed for a current node based on a size of the current node and a prediction mode of the current node, where the current node is an image block in a coding tree unit of a current image, the determination unit being further configured to determine a block partition policy for the current node based on the partition mode that is not allowed for the current node; and a prediction unit configured to obtain a coding block corresponding to the current node according to the block partition policy of the current node, and perform inter prediction on the corresponding coding block.

[0088] Regarding the twelfth aspect, in a first possible implementation example of the twelfth aspect, the decision unit Determining whether only inter prediction mode is used for predicting all coding blocks belonging to the current node, and determining whether the number of samples of the luma block of the current node is 32; and The method is configured to: determine that binary tree partitioning is a partitioning mode that is not permitted for the current node if it is determined that only inter prediction mode is used for predicting all coding blocks belonging to the current node and the number of samples in the luma block of the current node is determined to be 32.

[0089] With respect to the twelfth aspect or the first possible implementation example of the twelfth aspect, in a second possible implementation example of the twelfth aspect, the decision unit Determining whether only inter prediction mode is used for predicting all coding blocks belonging to the current node, and determining whether the number of samples of the luma block of the current node is 64; and The method is configured to: determine that ternary tree partitioning is the partitioning mode that is not permitted for the current node when it is determined that only inter prediction mode is used for predicting all coding blocks belonging to the current node and the number of samples of the luma block of the current node is determined to be 64.

[0090] For features and embodiments of the seventh, eighth, and ninth aspects of the present application, please refer to the features and embodiments of the method of the first aspect.

[0091] The method of the seventh aspect of the present application can be performed by the apparatus of the tenth aspect of the present application. For the functions of the apparatus of the tenth aspect of the present application and different embodiments of the apparatus, please refer to the features and embodiments of the method of the seventh aspect of the present application.

[0092] The method of the eighth aspect of the present application can be performed by the device of the eleventh aspect of the present application. For the functions of the device of the eleventh aspect of the present application and different embodiments of the device, please refer to the features and embodiments of the method of the eighth aspect of the present application.

[0093] The method of the ninth aspect of the present application can be performed by the apparatus of the twelfth aspect of the present application. For the functions of the apparatus of the twelfth aspect of the present application and different embodiments of the apparatus, please refer to the features and embodiments of the method of the ninth aspect of the present application.

[0094] A thirteenth aspect of the present application provides a video stream decoding device including a processor and a memory, the memory storing instructions that enable the processor to perform a method according to the seventh, eighth or ninth aspects.

[0095] A fourteenth aspect of the present application provides a video stream encoding device including a processor and a memory, the memory storing instructions that enable the processor to perform a method according to the seventh, eighth or ninth aspects.

[0096] A fifteenth aspect of the present application provides a computer-readable storage medium having stored thereon instructions that, when executed, enable one or more processors to encode video data, the instructions enabling the one or more processors to perform any one of the seventh, eighth, or ninth aspects, or possible implementations of the seventh, eighth, or ninth aspects.

[0097] A sixteenth aspect of the present application provides a computer program comprising program code which, when run on a computer, performs the method of the seventh, eighth or ninth aspect or any one of the possible implementations of the seventh, eighth or ninth aspect.

[0098] A seventeenth aspect of the present application provides a computer-readable storage medium. The computer-readable storage medium stores a bitstream, and the bitstream carries a prediction mode status flag of a current node of a current coding tree. When the value of the prediction mode status flag is a first value, it indicates that an inter prediction mode is used for all coding blocks belonging to the current node; or when the value of the prediction mode status flag is a second value, it indicates that an intra prediction mode is used for all coding blocks belonging to the current node.

[0099] It should be understood that the technical solutions of the second to seventeenth aspects of the present application are consistent with the technical solution of the first aspect of the present application, and the advantageous effects achieved by the aspects and corresponding feasible embodiments are similar, and the details will not be described again.

[0100] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

[0101] The present application provides an image prediction method, an apparatus, a system, a device, and a storage medium. The method includes the steps of obtaining a partition mode of a current node and determining whether an image block having a predetermined size is obtained by dividing the current node using the partition mode of the current node, the image block including a luma block or a chroma block. If an image block having the predetermined size is obtained by dividing the current node using the partition mode of the current node, intra prediction or inter prediction is performed on all coding blocks covered by the current node. According to the above method, intra prediction or inter prediction is performed on all coding blocks of the current node, allowing parallel processing to be performed on all coding blocks of the current node. This improves the processing performance of image prediction and increases the coding processing speed. [Brief explanation of the drawings]

[0102] [Figure 1A] 1 is a block diagram of an example video coding system 10 for implementing an embodiment of the present application; [Figure 1B] 1 is a block diagram of an example of a video coding system 40 for implementing an embodiment of the present application. [Figure 2] 2 is a block diagram of an exemplary structure of an encoder 20 for implementing an embodiment of the present application. [Figure 3] 3 is a block diagram of an exemplary structure of a decoder 30 for implementing an embodiment of the present application. [Figure 4] 4 is a block diagram of an example of a video coding device 400 for implementing an embodiment of the present application. [Figure 5] FIG. 10 is a block diagram of another example of an encoding device or a decoding device for implementing an embodiment of the present application. [Figure 6(a)] FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 6(b)]FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 6(c)] FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 6(d)] FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 6(e)] FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 6(f)] FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 6(g)] FIG. 1 is a schematic block diagram of a block division mode for implementing an embodiment of the present application; [Figure 7] FIG. 1 is a schematic block diagram of intra prediction for implementing an embodiment of the present application; [Figure 8] 1 is a schematic block diagram of a video communication system for implementing an embodiment of the present application; [Figure 9] 1 is a schematic flowchart of a first image prediction method according to an embodiment of the present application; [Figure 10] 1 is a schematic flowchart of a second image prediction method according to an embodiment of the present application; [Figure 11] 10 is a schematic flowchart of a third image prediction method according to an embodiment of the present application; [Figure 12] 10 is a schematic flowchart of a fourth image prediction method according to an embodiment of the present application; [Figure 13] 10 is a schematic flowchart of a fifth image prediction method according to an embodiment of the present application. [Figure 14] 10 is a schematic flowchart of a sixth image prediction method according to an embodiment of the present application. [Figure 15] 1 is a schematic structural diagram of the functions of an image prediction device according to an embodiment of the present application; [Figure 16] 1 is a schematic structural diagram of the hardware of a video encoding device according to an embodiment of the present application; [Figure 17]1 is a schematic structural diagram of the hardware of a video decoding device according to an embodiment of the present application; [Figure 18] 1 is a schematic structural diagram of an image prediction system according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0103] The following describes embodiments of the present application with reference to the accompanying drawings in which embodiments of the present application are presented. In the following description, reference is made to the accompanying drawings, which form a part of this disclosure and which illustrate, by way of example, certain aspects of the embodiments of the present application or in which the embodiments of the present application may be used. It should be understood that the embodiments of the present application may be used in other ways and may include structural or logical changes not shown in the accompanying drawings. Therefore, the following detailed description should not be construed as limiting, and the scope of the present application is defined by the appended claims. For example, it should be understood that content disclosed with respect to a described method may also apply to a corresponding apparatus or system configured to perform the method, and vice versa. For example, when one or more particular method steps are described, a corresponding apparatus may include one or more units, such as functional units, for performing the described method steps, even if such one or more units are not explicitly described or shown in the accompanying drawings. Furthermore, when describing a particular apparatus based on one or more units, such as, for example, functional units, a corresponding method may include one step used to perform one or more functions of one or more units (e.g., a step used to perform one or more functions of one or more units; or multiple steps each used to perform one or more functions of one or more units within multiple units), even if such one or more steps are not explicitly described or shown in the accompanying drawings. Furthermore, it should be understood that the features of various exemplary embodiments and / or aspects described herein can be combined with each other unless specified otherwise.

[0104] Video coding typically refers to the processing of a sequence of pictures, which form a video or video sequence. In the field of video coding, the terms "picture," "frame," and "image" may be used synonymously. Video coding, as used herein, refers to video encoding or video decoding. Video encoding is performed at a source and typically processes original video pictures (e.g., by compressing) to reduce the amount of data required to represent the video picture for more efficient storage and / or transmission. Video decoding is performed at a destination and typically involves the reverse processing compared to that of an encoder to reconstruct a video picture. The "coding" of a video picture in the embodiments should be understood as the "encoding" or "decoding" of a video sequence. The combination of the encoding and decoding parts is also called CODEC (encoding and decoding).

[0105] A video sequence includes a series of images (pictures), which are further divided into slices, and slices are further divided into blocks. Video coding processes are performed block by block. In some new video coding standards, the concept of a "block" is further expanded. For example, a macroblock can be further divided into multiple predictive blocks (partitions) for predictive coding. Alternatively, basic concepts such as a coding unit (CU), a prediction unit (PU), and a transform unit (TU) are used, multiple block units are obtained by functional partitioning, and an entirely new tree-based structure is used for description. For example, a CU can be divided into smaller CUs by quadtree partitioning, and the smaller CUs can be further divided to form a quadtree structure. A CU is a basic unit for dividing and coding a coding image. A similar tree structure can also exist for PUs and TUs. A PU may correspond to a predictive block and is the basic unit for predictive coding. A CU is further partitioned into multiple PUs in partition mode. A TU may correspond to a transform block, which is the basic unit for transforming a prediction residual, although CU, PU, ​​and TU are all essentially concepts of a block (or image block).

[0106] A CTU is divided into multiple CUs using a quad-tree structure, represented as a coding tree. Decisions regarding coding of picture regions by inter-picture (temporal) or intra-picture (spatial) prediction are made at the CU depth. Each CU can be further partitioned into one, two, or four PUs according to a PU partitioning pattern. Within a PU, the same prediction process is applied, and related information is transmitted to the decoder on a PU-by-PU basis. After obtaining residual blocks by applying a prediction process based on the PU partitioning pattern, the CU can be partitioned into transform units (TUs) based on another quad-tree structure similar to the coding tree used for CUs. Recent developments in video compression technology use quad-tree and binary tree (QTBT) partition frames to partition coding blocks. In the QTBT block structure, CUs can be square or rectangular.

[0107] In this specification, for ease of explanation and understanding, an image block to be coded in a current coding image may be referred to as a current block. For example, in encoding, the current block is the block currently being coded; and in decoding, the current block is the block currently being decoded. A decoded image block in a reference image used to predict a current block is referred to as a reference block. In other words, a reference block is a block that provides a reference signal to the current block, where the reference signal represents pixel values ​​in the image block. A block that provides a prediction signal to a current block in a reference image may be referred to as a prediction block, where the prediction signal represents pixel values, sample values, or sample signals in the prediction block. For example, after traversing multiple reference blocks, an optimal reference block is found, and the optimal reference block provides a prediction of the current block, where this block is referred to as a prediction block.

[0108] In the case of lossless video coding, the original video picture can be reconstructed. In other words, the reconstructed video picture has the same quality as the original video picture (assuming no transmission or other data loss occurs during storage or transmission). In the case of lossy video coding, further compression is performed, for example by quantization, to reduce the amount of data required to represent the video picture, and the video picture cannot be perfectly reconstructed at the decoder side. In other words, the quality of the reconstructed video picture is lower or inferior to the quality of the original video picture.

[0109] Some H.261 video coding standards are used for "lossy hybrid video coding" (i.e., spatial and temporal prediction in the sample domain are combined with 2D transform coding to apply quantization in the transform domain). Each picture of a video sequence is typically partitioned into a set of non-overlapping blocks, and coding is typically performed at the block level. In other words, at the encoder side, video is typically processed, i.e., encoded, at the block (video block) level, e.g., using spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to generate a predictive block, subtract the predictive block from a current block (the block currently being processed or to be processed) to obtain a residual block, transform the residual block, and quantize the residual block in the transform domain to reduce the amount of data to be transmitted (compressed), while at the decoder side, an inverse process compared to the encoder's process is applied to the coded or compressed block to reconstruct the current block for representation. Additionally, the encoder replicates the decoder processing loop, so that the encoder and decoder generate the same predictions (e.g., intra-prediction and inter-prediction) and / or reconstructions for processing, i.e., coding, subsequent blocks.

[0110] The following describes a system architecture to which an embodiment of the present application is applied. FIG. 1A is a schematic block diagram of an example of a video coding system 10 to which an embodiment of the present application is applied. As shown in FIG. 1A, the video coding system 10 may include a source device 12 and a destination device 14. The source device 12 generates encoded video data, and therefore the source device 12 may be referred to as a video encoding device. The destination device 14 can decode the encoded video data generated by the source device 12, and therefore the destination device 14 may be referred to as a video decoding device. The source device 12, the destination device 14, or various implementation solutions of the source device 12 or the destination device 14 may include one or more processors and memory coupled to the one or more processors. The memory may include, but is not limited to, RAM, ROM, EEPROM, flash memory, or any other medium usable for storing target program code in the form of computer-accessible instructions or data structures as described herein. The source device 12 and destination device 14 may include a variety of devices, including desktop computers, mobile computing devices, notebook (e.g., laptop) computers, tablet computers, set-top boxes, handheld phones such as "smartphones," television sets, cameras, display devices, digital media players, video game consoles, in-vehicle computers, wireless communication devices, or similar devices.

[0111] 1A depicts source device 12 and destination device 14 as separate devices, an embodiment of the devices may include both or both functions (source device 12 or corresponding function and destination device 14 or corresponding function). In such an embodiment, source device 12 or corresponding function and destination device 14 or corresponding function may be implemented using the same hardware and / or software, or using separate hardware and / or software, or any combination thereof.

[0112] The communication connection between source device 12 and destination device 14 may be implemented via link 13, and destination device 14 may receive encoded video data from source device 12 via link 13. Link 13 may include one or more media or equipment capable of moving encoded video data from source device 12 to destination device 14. In one example, link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real time. In this example, source device 12 may modulate the encoded video data according to a communication standard (e.g., a wireless communication protocol) and transmit the modulated video data to destination device 14. The one or more communication media may include wireless communication media and / or wired communication media, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The one or more communication media may form part of a packet-based network, such as a local area network, a wide area network, or a global network (e.g., the Internet). The communication medium(s) may include a router, a switch, a base station, or another device that facilitates communication from source device 12 to destination device 14 .

[0113] Source device 12 includes an encoder 20, and optionally, source device 12 may further include a picture source 16, a picture preprocessor 18, and a communications interface 22. In certain implementations, encoder 20, picture source 16, picture preprocessor 18, and communications interface 22 may be hardware components of source device 12 or may be software programs on source device 12. A detailed description follows.

[0114] Picture source 16 may include or be, for example, any type of picture capturing device configured to capture real-world pictures; and / or any type of device for generating pictures or comments (in the case of encoding screen content, some text on the screen is also considered part of the picture or image to be encoded), such as a computer graphics processor configured to generate computer-animated pictures; or any type of device configured to acquire and / or provide real-world or computer-animated pictures (e.g., screen content or virtual reality (VR) pictures); and / or any combination thereof (e.g., augmented reality (AR) pictures). Picture source 16 may be a camera configured to capture pictures or a memory configured to store pictures. Picture source 16 may further include any type of interface (internal or external) for storing previously captured or generated pictures and / or for acquiring or receiving pictures. If the picture source 16 is a camera, the picture source 16 may be, for example, a local camera or an integrated camera integrated into the source device. If the picture source 16 is a memory, the picture source 16 may be, for example, a local memory or an integrated memory integrated into the source device. If the picture source 16 includes an interface, the interface may be, for example, an external interface for receiving pictures from an external video source. The external video source may be, for example, an external picture capturing device such as a camera, an external memory, or an external picture generating device. The external picture generating device may be, for example, an external computer graphics processor, a computer, or a server. The interface may be any type of interface, for example, a wired or wireless interface, or an optical interface, according to any proprietary or standardized interface protocol.

[0115] A picture can be considered a two-dimensional array or matrix of picture elements. A picture element in the array may also be referred to as a sample. The number of samples in the horizontal and vertical directions (or axes) of the array or picture defines the size and / or resolution of the picture. Three color components are typically used to represent color. For example, a picture may be represented as or include three sample arrays. For example, in an RGB format or color space, a picture includes corresponding red, green, and blue sample arrays. However, in video coding, each pixel is typically represented in a luminance / chrominance format or color space. For example, a YUV format picture includes a luminance component denoted Y (although L may be used instead) and two chrominance components denoted U and V. The luminance (luma) component Y represents brightness or gray-level intensity (e.g., both are the same in a grayscale picture), while the two chrominance (chroma) components U and V represent chromaticity or color information components. Thus, a picture in YUV format includes a luma sample array of luma sample values ​​(Y) and two chroma sample arrays of chroma values ​​(U and V). A picture in RGB format can be converted or transformed into a picture in YUV format, and vice versa; this process is also known as color conversion or transformation. If the picture is monochrome, the picture may include only a luma sample array. In this embodiment of the present application, the image sent by the picture source 16 to the picture processor may also be referred to as raw picture data 17.

[0116] The picture preprocessor 18 is configured to receive raw picture data 17 and preprocess the raw picture data 17 to obtain a preprocessed picture 19 or preprocessed picture data 19. The preprocessing performed by the picture preprocessor 18 may include cropping, color format conversion (e.g., from RGB format to YUV format), color correction, or noise removal.

[0117] Encoder 20 (also referred to as video encoder 20) is configured to receive preprocessed picture data 19, process the preprocessed picture data 19 using an associated prediction mode (such as the prediction mode of each embodiment herein), and provide encoded picture data 21. (Details of the structure of encoder 20 are further described below with reference to FIG. 2, FIG. 4, or FIG. 5.) In some embodiments, encoder 20 may be configured to perform the embodiments described below to implement the encoder-side application of chroma block prediction methods described herein.

[0118] The communications interface 22 may be configured to receive the coded picture data 21 and transmit the coded picture data 21 to the destination device 14 or any other device (e.g., memory) via the link 13 for storage or direct reconstruction. The any other device may be any device used for decoding or storage. The communications interface 22 may be configured, for example, to package the coded picture data 21 into an appropriate format, such as data packets, for transmission via the link 13.

[0119] The destination device 14 includes a decoder 30, and optionally, the destination device 14 may further include a communication interface 28, a picture post-processor 32, and a display device 34. Each of these is described below.

[0120] The communication interface 28 may be configured to receive the coded picture data 21 from the source device 12 or any other source. The other source may be, for example, a storage device, which may be, for example, a storage device for coded picture data. The communication interface 28 may be configured to transmit or receive the coded picture data 21 via the link 13 between the source device 12 and the destination device 14 or via any type of network. The link 13 may be, for example, a direct wired or wireless connection, and the type of network may be, for example, a wired or wireless network or any combination thereof, or any type of private or public network, or any combination thereof. The communication interface 28 may be configured, for example, to de-package data packets transmitted via the communication interface 22 to obtain the coded picture data 21.

[0121] Both communication interface 28 and communication interface 22 may be configured as unidirectional or bidirectional communication interfaces, for example, to send and receive messages to set up a connection, verify and exchange communications links and / or any other information related to data transmission, such as encoded picture data transmission.

[0122] Decoder 30 (also referred to as decoder 30) is configured to receive encoded picture data 21 and provide decoded picture data 31 or decoded picture 31 (details of the structure of decoder 30 are described further below with reference to Figure 3, Figure 4 or Figure 5). In some embodiments, decoder 30 may be configured to perform the embodiments described below in order to implement the decoder-side application of chroma block prediction methods described herein.

[0123] The picture post-processor 32 is configured to post-process the decoded picture data 31 (also called reconstructed picture data) to obtain post-processed picture data 33. The post-processing performed by the picture post-processor 32 may include color format conversion (e.g., from YUV format to RGB format), color correction, cropping, resampling, or any other processing. The picture post-processor 32 may further be configured to send the post-processed picture data 33 to a display device 34.

[0124] The display device 34 is configured to receive the post-processed picture data 33 and display the picture, for example to a user or viewer. The display device 34 may be or include any type of display configured to present the reconstructed picture, and may be, for example, an integrated or external display or monitor. For example, the display may include a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS), a digital light processor (DLP), or any other type of display.

[0125] 1A depicts source device 12 and destination device 14 as separate devices, an embodiment of the devices may include both or both functions (source device 12 or corresponding function, and destination device 14 or corresponding function). In such an embodiment, source device 12 or corresponding function and destination device 14 or corresponding function may be implemented using the same hardware and / or software, or using separate hardware and / or software, or any combination thereof.

[0126] One skilled in the art can understand that, based on the description, the presence and (exact) division of the functions of the source device 12 and / or the destination device 14 shown in FIG. 1A or the functions of different units may vary depending on the actual devices and applications. The source device 12 and the destination device 14 can each be any one of a wide range of devices including any type of handheld or fixed device, such as a notebook or laptop computer, mobile phone, smartphone, pad or tablet computer, video camera, desktop computer, set-top box, television, camera, in-vehicle device, display device, digital media player, video game console, video streaming device (such as a content service server or content distribution server, etc.), broadcast receiver device, or broadcast transmitter device, and may or may not use any type of operating system, or may use its operating system.

[0127] The encoder 20 and the decoder 30 can each be implemented as any of a variety of suitable circuits, such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware, or any combination thereof. When the technology is partially realized using software, the device can store software instructions in a suitable non-transitory computer-readable storage medium and use hardware such as one or more processors to execute the instructions to implement the technology of the present disclosure. Any of the foregoing (including hardware, software, combinations of hardware and software, etc.) can be regarded as one or more processors.

[0128] 1A is merely an example, and the present technology is applicable to video coding settings (e.g., video encoding or video decoding) that do not necessarily include any data communication between an encoder and a decoder. In other examples, data may be retrieved from local memory, streamed over a network, etc. A video encoder may encode data and store the encoded data in memory, and / or a video decoder may retrieve data from memory and decode the data. In some examples, encoding and decoding are performed by devices that do not communicate with each other but simply encode data to memory and / or retrieve data from memory and decode the data.

[0129] 1B is an illustrative diagram of an example video coding system 40 including the encoder 20 of FIG. 2 and / or the decoder 30 of FIG. 3, according to an example embodiment. The video coding system 40 may implement a combination of various techniques in embodiments of the present application. In the illustrated implementation, the video coding system 40 may include an imaging device 41, the encoder 20, the decoder 30 (and / or a video encoder / decoder implemented by logic 47 of a processing unit 46), an antenna 42, one or more processors 43, one or more memories 44, and / or a display device 45.

[0130] 1B, imaging device 41, antenna 42, processing unit 46, logic circuitry 47, encoder 20, decoder 30, processor 43, memory 44, and / or display device 45 may be in communication with one another. As discussed, although video coding system 40 is shown using encoder 20 and decoder 30, video coding system 40 may include only encoder 20 or only decoder 30 in different examples.

[0131] In some examples, antenna 42 may be configured to transmit or receive an encoded bitstream of video data. Further, in some examples, display device 45 may be configured to present the video data. In some examples, logic 47 may be implemented by processing unit 46. Processing unit 46 may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, etc. Video coding system 40 may alternatively include optional processor 43. Optional processor 43 may also include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, etc. In some examples, logic 47 may be implemented by hardware, e.g., dedicated video coding hardware, and processor 43 may be implemented by general-purpose software, an operating system, etc. Furthermore, memory 44 may be any type of memory, such as volatile memory (e.g., static random access memory (SRAM)), dynamic random access memory (DRAM), or non-volatile memory (e.g., flash memory). In a non-limiting example, memory 44 may be implemented by cache memory. In some examples, logic circuitry 47 may access memory 44 (e.g., for implementing an image buffer). In other examples, logic circuitry 47 and / or processing unit 46 may include memory (e.g., cache) for implementing an image buffer, etc.

[0132] In some examples, encoder 20 implemented by logic circuitry may include an image buffer (e.g., implemented by processing unit 46 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include encoder 20 implemented by logic circuitry 47 to implement various modules described with reference to FIG. 2 and / or any other encoder system or subsystem described herein. The logic circuitry may be configured to perform various operations described herein.

[0133] In some examples, decoder 30 may be implemented by logic circuitry 47 in a similar manner to implement the various modules described with reference to decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein. In some examples, decoder 30 implemented by logic circuitry may include an image buffer (e.g., implemented by processing unit 2820 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include decoder 30 implemented by logic circuitry 47 to implement the various modules described with reference to FIG. 3 and / or any other decoder system or subsystem described herein.

[0134] In some examples, antenna 42 may be configured to receive an encoded bitstream of video data. As described, the encoded bitstream may include data, indicators, index values, mode selection data, etc., related to video frame coding as described herein, such as data related to coding partitioning (e.g., transform coefficients or quantized transform coefficients, optional indicators (as described), and / or data defining the coding partitioning). Video coding system 40 may further include a decoder 30 coupled to antenna 42 and configured to decode the encoded bitstream. Display device 45 is configured to present the video frames.

[0135] In this embodiment of the present application, in the examples described with reference to encoder 20, it should be understood that decoder 30 may be configured to perform the reverse process. With respect to signaling syntax elements, decoder 30 may be configured to receive and parse such syntax elements and correspondingly decode associated video data. In some examples, encoder 20 may entropy encode syntax elements into the coded video bitstream. In such examples, decoder 30 may parse such syntax elements and correspondingly decode associated video data.

[0136] It should be noted that the decoding method described in this embodiment of the present application is mainly used in the decoding process, which exists in both the encoder 20 and the decoder 30.

[0137] Figure 2 is a schematic / conceptual block diagram of an example of an encoder 20 configured to implement an embodiment of the present application. In the example of Figure 2, the encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter unit 220, a decoded picture buffer (DPB) 230, a prediction processing unit 260, and an entropy coding unit 270. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The encoder 20 shown in Figure 2 may also be referred to as a hybrid video encoder or a video encoder based on a hybrid video codec.

[0138] For example, the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260, and the entropy coding unit 270 form a forward signal path of the encoder 20, while for example, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, and the prediction processing unit 260 form a backward signal path of the encoder. The backward signal path of the encoder corresponds to the signal path of the decoder (see decoder 30 in FIG. 3).

[0139] Encoder 20 receives, for example, via input 202, a picture 201 or an image block 203 of picture 201, e.g., a picture in a series of pictures forming a video or a video sequence. Image block 203 may also be called a current picture block or a picture block to be coded. Picture 201 may also be called a current picture or a picture to be coded (particularly in video coding, to distinguish the current picture from other pictures, e.g., previously coded and / or decoded pictures in the same video sequence, i.e., a video sequence that also includes the current picture).

[0140] An embodiment of encoder 20 may include a partitioning unit (not shown in FIG. 2) configured to partition picture 201 into multiple blocks, such as image blocks 203. Picture 201 is typically partitioned into multiple non-overlapping blocks. The partitioning unit may be configured to use the same block size for all pictures in a video sequence and use a corresponding grid that defines the block sizes, or to vary the block size among pictures or subsets or groups of pictures and partition each picture into corresponding blocks.

[0141] In one example, prediction processing unit 260 of encoder 20 may be configured to perform any combination of the above partitioning techniques.

[0142] Similar to picture 201, image block 203 may also be or may be considered as a two-dimensional array or matrix of samples having sample values, although the size of image block 203 is smaller than the size of picture 201. In other words, image block 203 may include, for example, one sample array (e.g., a luma array in the case of a monochrome picture 201), three sample arrays (e.g., one luma array and two chroma arrays in the case of a color picture), or any other quantity and / or type of arrays depending on the applied color format. The number of samples in the horizontal and vertical directions (or axial directions) of image block 203 defines the size of image block 203.

[0143] The encoder 20 shown in FIG. 2 is configured to code a picture 201 block-by-block, eg, to encode and predict each image block 203 .

[0144] The residual calculation unit 204 is configured to calculate the residual block 205 based on the picture image block 203 and the prediction block 265 (further details regarding the prediction block 265 are provided below), for example, to obtain the residual block 205 in the sample domain by subtracting the sample values ​​of the prediction block 265 from the sample values ​​of the picture image block 203 sample by sample (pixel by pixel).

[0145] The transform processing unit 206 is configured to apply a transform, such as a discrete cosine transform (DCT) or a discrete sine transform (DST), to the sample values ​​of the residual block 205 to obtain transform coefficients 207 in a transform domain. The transform coefficients 207 may also be referred to as transform residual coefficients and represent the residual block 205 in the transform domain.

[0146] The transform processing unit 206 may be configured to apply an integer approximation of a DCT / DST, such as a transform specified by AVS, AVS2, or AVS3. Compared to an orthogonal DCT transform, such an integer approximation is typically scaled by a specific factor. Applying additional scale factors to preserve the norm of the residual blocks processed by the forward and inverse transforms is part of the transform process. The scale factors are typically selected based on some constraints. For example, the scale factors may be a power of two for the shift operation, the bit depth of the transform coefficients, a trade-off between accuracy and implementation cost, etc. A specific scale factor may be specified for the inverse transform, e.g., by the inverse transform processing unit 212 on the decoder side 30 (and a corresponding inverse transform, e.g., by the inverse transform processing unit 212 on the encoder side 20), and the corresponding scale factor for the forward transform, e.g., by the transform processing unit 206 on the encoder side 20, may be specified accordingly.

[0147] The quantization unit 208 is configured to quantize the transform coefficients 207 to obtain quantized transform coefficients 209, for example, by applying scalar quantization or vector quantization. The quantized transform coefficients 209 may also be referred to as quantized residual coefficients 209. The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, an n-bit transform coefficient may be truncated to an m-bit transform coefficient during quantization, where n is greater than m. The quantization degree may be modified by adjusting a quantization parameter (QP). For example, in the case of scalar quantization, different scales may be applied to achieve finer or coarser quantization. A smaller quantization step corresponds to finer quantization, while a larger quantization step corresponds to coarser quantization. An appropriate quantization step size may be indicated by the quantization parameter (QP). The quantization parameter may, for example, be an index into a predefined set of appropriate quantization step sizes. For example, a smaller quantization parameter may correspond to finer quantization (smaller quantization step size), and a larger quantization parameter may correspond to coarser quantization (larger quantization step size), or vice versa. Quantization may include division by the quantization step size and corresponding quantization and / or inverse quantization, or may include multiplication by the quantization step size, for example, performed by the inverse quantization unit 210. In embodiments according to some standards, such as AVS, AVS2, and AVS3, the quantization parameter may be used to determine the quantization step size. Generally, the quantization step size may be calculated based on the quantization parameter using a fixed-point approximation of an equation that includes a division. To restore the norm of the residual block, an additional scaling factor may be introduced into the quantization and dequantization, where the norm of the residual block may be modified due to the scale used in the fixed-point approximation of the quantization step size and quantization parameter equation.In an exemplary implementation, the inverse transform and dequantization scales may be combined. Alternatively, customized quantization tables may be used and signaled from the encoder to the decoder, for example, in the bitstream. Quantization is a lossy operation, where larger quantization step sizes result in larger losses.

[0148] The inverse quantization unit 210 is configured to apply the inverse quantization of the quantization unit 208 to the quantized coefficients to obtain dequantized coefficients 211, e.g., to apply an inverse quantization scheme of the quantization scheme applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208. The dequantized coefficients 211, also referred to as dequantized residual coefficients 211, correspond to the transform coefficients 207 but are typically not identical to the transform coefficients due to loss due to quantization.

[0149] The inverse transform processing unit 212 is configured to apply an inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST), to obtain an inverse transform block 213 in the sample domain. The inverse transform block 213 may also be referred to as an inverse transform dequantization block 213 or an inverse transform residual block 213.

[0150] The reconstruction unit 214 (e.g., summer 214) is configured to add the inverse transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265, e.g., by adding the sample values ​​of the reconstructed residual block 213 and the sample values ​​of the prediction block 265, to obtain the reconstructed block 215 in the sample domain.

[0151] Optionally, a buffer unit 216 (or "buffer" 216 for short), e.g., of the line buffer 216, is configured to buffer or store the reconstructed block 215 and corresponding sample values, e.g., for intra-prediction. In other embodiments, the encoder may be configured to use the unfiltered reconstructed block and / or corresponding sample values ​​stored in the buffer unit 216 for any type of estimation and / or prediction, e.g., intra-prediction.

[0152] For example, one embodiment of encoder 20 may be configured such that buffer unit 216 is not only used to store reconstructed blocks 215 for intra prediction unit 254, but also for loop filter unit 220 (not shown in FIG. 2), and / or that buffer unit 216 and decoded picture buffer unit 230 form one buffer, for example. In other embodiments, filtered blocks 221 and / or blocks or samples from decoded picture buffer 230 (blocks or samples not shown in FIG. 2) are used as input to or a basis for intra prediction unit 254.

[0153] Loop filter unit 220 (briefly referred to as “loop filter” 220) is configured to filter reconstructed block 215 to obtain filtered block 221 to smooth pixel transitions or improve video quality. Loop filter unit 220 is intended to represent one or more loop filters, including, for example, a deblocking filter, a sample-adaptive offset (SAO) filter, or another filter, such as a bilateral filter, an adaptive loop filter (ALF), a sharpening or smoothing filter, or a collaborative filter. Although loop filter unit 220 is shown in FIG. 2 as an in-loop filter, in another configuration, loop filter unit 220 may be implemented as a post-loop filter. Filtered block 221 may also be referred to as filtered reconstruction block 221. Decoded picture buffer 230 may store the reconstructed coding block after loop filter unit 220 performs a filtering operation on the reconstructed coding block.

[0154] In one embodiment, the encoder 20 (and correspondingly, the loop filter unit 220) may be configured to output loop filter parameters (such as sample adaptive offset information), e.g., directly or after entropy coding performed by the entropy coding unit 270 or any other entropy coding unit, so that, e.g., the decoder 30 can receive the same loop filter parameters and apply the same loop filter parameters for decoding.

[0155] The decoded picture buffer (DPB) 230 may be a reference picture memory that stores reference picture data for encoding video data by the encoder 20. The DPB 230 may be formed by any one of a variety of memory devices, such as dynamic random access memory (DRAM) (including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), and resistive RAM (RRAM)), or another type of memory device. The DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices. In one example, the decoded picture buffer (DPB) 230 is configured to store the filtered block 221. The decoded picture buffer 230 may be further configured to store another previously filtered block, e.g., previously reconstructed and filtered block 221, of the same current picture or a different picture, e.g., a previously reconstructed picture, and may provide a fully previously reconstructed, i.e., decoded, picture (and corresponding reference blocks and samples) and / or a partially reconstructed current picture (and corresponding reference blocks and samples), e.g., for inter-prediction. In one example, the decoded picture buffer (DPB) 230 is configured to store the reconstructed block 215 when the reconstructed block 215 is reconstructed without in-loop filtering.

[0156] The prediction processing unit 260, also referred to as block prediction processing unit 260, is configured to receive or obtain an image block 203 (the current image block 203 of the current picture 201) and reconstructed picture data, e.g., reference samples of the same (current) picture from the buffer 216 and / or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and to process such data for prediction, i.e., to provide a prediction block 265, which may be an inter prediction block 245 or an intra prediction block 255.

[0157] The mode selection unit 262 may be configured to select a prediction mode (e.g., intra prediction mode or inter prediction mode) and / or a corresponding prediction block 245 or 255 to be used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstruction block 215.

[0158] In one embodiment, mode selection unit 262 may be configured to select a prediction mode (e.g., from prediction modes supported by prediction processing unit 260) that provides the best match or smaller residual (smaller residual means better compression for transmission or storage), or that provides less signaling overhead (smaller signaling overhead means better compression for transmission or storage), or that considers or balances both. Mode selection unit 262 may be configured to determine the prediction mode based on rate distortion optimization (RDO), i.e., select a prediction mode that provides the smallest rate distortion, or select a prediction mode whose associated rate distortion at least meets a selection criterion for the prediction mode.

[0159] The prediction processing performed (eg, using prediction processing unit 260) and mode selection performed (eg, using mode selection unit 262) according to an example of encoder 20 are described in detail below.

[0160] As noted above, encoder 20 is configured to determine or select an optimal or best prediction mode from a (predetermined) set of prediction modes, which may include, for example, intra-prediction modes and / or inter-prediction modes.

[0161] The set of intra-prediction modes may include 35 different intra-prediction modes, e.g., omni-directional modes such as DC (or average) mode and planar mode, or directional modes specified in H.265, or may include 67 different intra-prediction modes, e.g., omni-directional modes such as DC (or average) mode and planar mode, or directional modes specified in the currently developing H.266.

[0162] In a possible implementation, the set of inter prediction modes depends on the available reference pictures (i.e., at least some of the decoded pictures stored in DBP 230 as described above), and other inter prediction parameters, such as whether the entire reference picture is used or only a portion of the reference picture, e.g., a best-matching reference block found in a search window region surrounding the region of the current block, is used, and / or whether pixel interpolation, such as half-pixel and / or quarter-pixel interpolation, is applied. The set of inter prediction modes may include, for example, an Advanced Motion Vector Prediction (AMVP) mode and a merge mode. In a particular implementation, the set of inter prediction modes may include, in this embodiment of the present application, an improved control point-based AMVP mode and an improved control point-based merge mode. In one example, intra prediction unit 254 may be configured to perform any combination of the inter prediction techniques described below.

[0163] In addition to the aforementioned prediction modes, skip mode and / or direct mode may also be used in this embodiment of the present application.

[0164] The prediction processing unit 260 may be further configured to partition the image block 203 into smaller block partitions or sub-blocks, e.g., using quad-tree (QT) partitioning, binary-tree (BT) partitioning, ternary tree (TT) partitioning, extended quad-tree (EQT) partitioning, or any combination thereof iteratively, and perform prediction for each block partition or sub-block, e.g., where mode selection includes selecting a tree structure for the partitioned image block 203 and selecting a prediction mode to be applied to each block partition or sub-block.

[0165] The inter prediction unit 244 may include a motion estimation (ME) unit (not shown in FIG. 2) and a motion compensation (MC) unit (not shown in FIG. 2). The motion estimation unit is configured to receive or obtain the picture image block 203 (the current picture image block 203 of the current picture 201) and the decoded picture 231, or at least one or more previously reconstructed blocks, such as reconstructed blocks of one or more other / different previously decoded pictures 231 for motion estimation. For example, a video sequence may include the current picture and the previously decoded picture 31. In other words, the current picture and the previously decoded picture 31 may be part of or form a sequence of pictures that form the video sequence.

[0166] For example, the encoder 20 may be configured to select a reference block from multiple reference blocks in the same picture or a different one of multiple other pictures, provide the reference picture to a motion estimation unit (not shown in FIG. 2 ), and / or provide an offset (spatial offset) between the position of the reference block (coordinates X and Y) and the position of the current block as an inter-prediction parameter, also called a motion vector (MV).

[0167] The motion compensation unit is configured to obtain inter prediction parameters and perform inter prediction based on or using the inter prediction parameters to obtain inter prediction block 245. Motion compensation performed by the motion compensation unit (not shown in FIG. 2 ) may include fetching or generating a prediction block based on a motion / block vector determined by motion estimation (possibly performing sub-pixel accurate interpolation). Interpolation filtering can generate additional pixel samples from known pixel samples, thereby potentially increasing the number of candidate prediction blocks that can be used to code the picture block. Upon receiving the motion vector for the PU of the current picture block, the motion compensation unit 246 can locate the prediction block to which the motion vector points within one reference picture list. The motion compensation unit 246 can further generate syntax elements associated with blocks and video slices for decoding the picture blocks of the video slices by decoder 30.

[0168] Specifically, the inter prediction unit 244 may transmit a syntax element to the entropy encoding unit 270, where the syntax element includes inter prediction parameters (e.g., index information of an inter prediction mode selected for predicting a current block after traversing multiple inter prediction modes). In a possible application scenario, when there is only one inter prediction mode, the inter prediction parameters may not be transmitted in the syntax element. In this case, the decoder side 30 may directly use a default prediction mode for decoding. It may be understood that the inter prediction unit 244 may be configured to perform any combination of inter prediction techniques.

[0169] The intra prediction unit 254 is configured, for example, to obtain the picture block 203 (current picture block) and one or more previously reconstructed blocks of the same picture, e.g., reconstructed neighboring blocks, for intra estimation. For example, the encoder 20 may be configured to select an intra prediction mode from a plurality of (predetermined) intra prediction modes.

[0170] In one embodiment, the encoder 20 may be configured to select an intra prediction mode according to an optimization criterion, for example, based on a smaller residual (e.g., the intra prediction mode that provides the predicted block 255 that is most similar to the current picture block 203) or minimum bitrate distortion.

[0171] The intra prediction unit 254 is further configured to determine the intra-predicted block 255 based on, for example, intra prediction parameters of the selected intra prediction mode. In either case, after selecting an intra prediction mode for the block, the intra prediction unit 254 is further configured to provide the intra prediction parameters, i.e., information indicating the selected intra prediction mode for the block, to the entropy coding unit 270. In one example, the intra prediction unit 254 may be configured to perform any combination of intra prediction techniques.

[0172] Specifically, the intra prediction unit 254 can send a syntax element to the entropy encoding unit 270, where the syntax element includes intra prediction parameters (e.g., indicator information of an intra prediction mode selected for predicting a current block after traversing multiple intra prediction modes). In a possible application scenario, if there is only one intra prediction mode, the intra prediction parameters may not be transmitted in the syntax element. In this case, the decoder side 30 can directly use the default prediction mode for decoding.

[0173] The entropy coding unit 270 is configured to apply (or bypass) an entropy coding algorithm or scheme (e.g., a variable length coding (VLC) scheme, a context adaptive VLC (CAVLC) scheme, an arithmetic coding scheme, context adaptive binary arithmetic coding (CABAC), syntax-based context adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or another entropy coding method or technique) to one or all of the following (the quantization coefficients 209, the inter-prediction parameters, the intra-prediction parameters, and / or the loop filter parameters) to obtain coded picture data 21, which may be output via output 272, e.g., in the form of a coded bitstream 21. The coded bitstream may be transmitted to the video decoder 30, archived for later transmission, or retrieved by the video decoder 30. Entropy encoding unit 270 may further be configured to entropy encode another syntax element of the current video slice being encoded.

[0174] Other structural variations of the video encoder 20 may be configured to encode the video stream. For example, a non-transform-based encoder 20 may directly quantize the residual signal for some blocks or frames without the transform processing unit 206. In another implementation, the encoder 20 may include the quantization unit 208 and the inverse quantization unit 210 combined into a single unit.

[0175] Specifically, in this embodiment of the present application, the encoder 20 may be configured to implement the video encoding methods described in the following embodiments.

[0176] It should be understood that other structural variations of the video encoder 20 may be configured to encode the video stream. For example, for some image blocks or image frames, the video encoder 20 may directly quantize the residual signal without processing by the transform processing unit 206, and therefore without processing by the inverse transform processing unit 212. Alternatively, for some image blocks or image frames, the video encoder 20 may not generate residual data, and therefore the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, and the inverse transform processing unit 212 need not perform any processing. Alternatively, the video encoder 20 may directly store the reconstructed image block as a reference block without processing by the filter 220. Alternatively, the quantization unit 208 and the inverse quantization unit 210 may be combined together within the video encoder 20. The loop filter 220 is optional, and in the case of lossless compression coding, the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, and the inverse transform processing unit 212 are optional. It should be understood that the inter prediction unit 244 and the intra prediction unit 254 can be selectively enabled according to different application scenarios.

[0177] 3 is a schematic / conceptual block diagram of an example of a decoder 30 configured to implement an embodiment of the present application. Video decoder 30 is configured to receive coded picture data (e.g., coded bitstream) 21, e.g., resulting from encoding by encoder 20, to obtain decoded pictures 231. During decoding, video decoder 30 receives video data from video encoder 20, e.g., a coded video bitstream representing picture blocks of coded video slices, and associated syntax elements.

[0178] 3, decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g., summer 314), a buffer 316, a loop filter 320, a decoded picture buffer 330, and a prediction processing unit 360. Prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362. In some examples, video decoder 30 may perform a decoding process that is generally the reverse of the encoding process described with respect to video encoder 20 of FIG.

[0179] Entropy decoding unit 304 is configured to entropy decode coded picture data 21 to obtain, e.g., quantized coefficients 309 and / or decoded coding parameters (not shown in FIG. 3), e.g., any one or all of (decoded) inter-prediction parameters, intra-prediction parameters, loop filter parameters, and / or other syntax elements. Entropy decoding unit 304 is further configured to forward the inter-prediction parameters, intra-prediction parameters, and / or other syntax elements to prediction processing unit 360. Video decoder 30 may receive syntax elements at the video slice level and / or the video block level.

[0180] The inverse quantization unit 310 may have the same functionality as the inverse quantization unit 110. The inverse transform processing unit 312 may have the same functionality as the inverse transform processing unit 212. The reconstruction unit 314 may have the same functionality as the reconstruction unit 214. The buffer 316 may have the same functionality as the buffer 216. The loop filter 320 may have the same functionality as the loop filter 220. The decoded picture buffer 330 may have the same functionality as the decoded picture buffer 230.

[0181] Prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354. The inter prediction unit 344 may be similar in function to the inter prediction unit 244, and the intra prediction unit 354 may be similar in function to the intra prediction unit 254. Prediction processing unit 360 is typically configured to perform block prediction and / or obtain a prediction block 365 from the coded data 21, and to receive or obtain (explicitly or implicitly) prediction-related parameters and / or information regarding a selected prediction mode, for example, from entropy decoding unit 304.

[0182] If a video slice is coded as an intra-coded (I) slice, intra prediction unit 354 of prediction processing unit 360 is configured to generate a prediction block 365 of a picture block of the current video slice based on a signaled intra prediction mode and data from a previously decoded block of the current frame or picture. If a video frame is coded as an inter-coded (B or P) slice, inter prediction unit 344 (e.g., a motion compensation unit) of prediction processing unit 360 is configured to generate a prediction block 365 of a video block of the current video slice based on a motion vector and another syntax element received from entropy decoding unit 304. For inter prediction, the prediction block may be generated from one of the reference pictures in one reference picture list. Video decoder 30 may construct the reference frame lists (List 0 and List 1) using a default construction technique based on the reference pictures stored in DPB 330.

[0183] Prediction processing unit 360 is configured to determine a predictive block for a video block of a current video slice by analyzing the motion vector and another syntax element, and to generate the predictive block for the current video block being decoded using the predictive block. In one example of the present application, prediction processing unit 360 uses some of the received syntax elements to determine the prediction mode (e.g., intra-prediction or inter-prediction) used to code the video blocks of the video slice, the inter-prediction slice type (e.g., B slice, P slice, or GPB slice), configuration information of one or more reference picture lists of the slice, the motion vector for each inter-coded video block of the slice, the inter-prediction status of each inter-coded video block of the slice, and other information for decoding the video blocks of the current video slice. In another example of the present disclosure, the syntax elements received by video decoder 30 from the bitstream include one or more syntax elements of an adaptive parameter set (APS), a sequence parameter set (SPS), a picture parameter set (PPS), or a slice header.

[0184] Inverse quantization unit 310 may be configured to inverse quantize (i.e., dequantize) the quantized transform coefficients provided in the bitstream and decoded by entropy decoding unit 304. The inverse quantization process may include using quantization parameters calculated by video encoder 20 for each video block in a video slice to determine the degree of quantization to apply, and similarly, to determine the degree of inverse quantization to apply.

[0185] The inverse transform processing unit 312 is configured to apply an inverse transform (eg, an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients to produce residual blocks in the pixel domain.

[0186] The reconstruction unit 314 (e.g., adder 314) is configured to add the inverse transform block 313 (i.e., the reconstructed residual block 313) to the prediction block 365 to obtain the reconstructed block 315 in the sample domain, for example, by adding the sample values ​​of the reconstructed residual block 313 and the sample values ​​of the prediction block 365.

[0187] The loop filter unit 320 (during or after the coding loop) is configured to filter the reconstructed block 315 to obtain a filtered block 321 to smooth pixel transitions or improve video quality. In one example, the loop filter unit 320 is configured to perform any combination of the filtering techniques described below. The loop filter unit 320 is intended to represent one or more loop filters, including, for example, a deblocking filter, a sample-adaptive offset (SAO) filter, or another filter, such as a bilateral filter, an adaptive loop filter (ALF), a sharpening or smoothing filter, or a collaborative filter. Although the loop filter unit 320 is shown in FIG. 3 as an in-loop filter, in another configuration, the loop filter unit 320 may be implemented as a post-loop filter.

[0188] The decoded video blocks 321 of a given frame or picture are then stored in a decoded picture buffer 330, which stores reference pictures used for subsequent motion compensation.

[0189] The decoder 30 is arranged to output the decoded pictures 31 via an output 332, for example for presentation to or viewing by a user.

[0190] Other variations of the video decoder 30 may be configured to decode the compressed bitstream. For example, the decoder 30 may generate the output video stream without processing by the loop filter unit 320. For example, a non-transform-based decoder 30 may directly inverse quantize the residual signal for some blocks or frames, without the inverse transform processing unit 312. In another implementation, the video decoder 30 may include the inverse quantization unit 310 and the inverse transform processing unit 312 combined into a single unit.

[0191] Specifically, in this embodiment of the present application, the decoder 30 is configured to implement the decoding method described in the following embodiments.

[0192] It should be understood that the block partitioning operation may be performed by the prediction processing unit 360 or an independent unit (not shown). The prediction processing unit 360 may be configured to partition the image block 203 into smaller block partitions or sub-blocks, for example, using quad-tree (QT) partitioning, binary-tree (BT) partitioning, triple-tree (TT) partitioning, extended quad-tree (EQT) partitioning, or any combination thereof, repeatedly, perform prediction for each block partition or sub-block (where the partitioning mode is determined according to a predetermined rule or based on a parsed syntax element used to indicate the partitioning mode), and then predict each block partition or sub-block, for example. The mode selection includes selecting a tree structure for the partitioned image block 203 and selecting a prediction mode to be applied to each block partition or sub-block.

[0193] It should be understood that other structural variations of the video decoder 30 may be configured to decode an encoded video bitstream. For example, the video decoder 30 may generate an output video stream without processing by the filter 320. Alternatively, for some image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not obtain quantized coefficients by decoding, and therefore the inverse quantization unit 310 and the inverse transform processing unit 312 do not need to perform processing. The loop filter 320 is optional. In the case of lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional. It should be understood that the inter prediction unit and the intra prediction unit may be selectively enabled according to different application scenarios.

[0194] It should be understood that with respect to the encoder 20 and decoder 30 of the present application, the processing result of a stage may be further processed before being output to the next stage, for example, after the stages of interpolation filtering, motion vector derivation, loop filtering, etc., further operations such as clipping or shifting may be performed on the processing result of the corresponding stage.

[0195] For example, the motion vectors of the control points of the current image block or the motion vectors of the sub-blocks of the current picture block derived from the motion vectors of neighboring affine-coded blocks may be further processed. This is not limited to the present application. For example, the value of the motion vector is restricted within a specific bit width. If the allowed bit width of the motion vector is bitDepth, the value of the motion vector ranges from -2^(bitDepth-1) to 2^(bitDepth-1)-1, where the symbol "^" represents exponentiation. When bitDepth is 16, the value ranges from -32768 to 32767. When bitDepth is 18, the value ranges from -131072 to 131071. As another example, the value of the motion vector (e.g., the motion vector MV of four 4x4 sub-blocks in an 8x8 image block) is restricted so that the maximum difference between the integer parts of the MVs of the four 4x4 sub-blocks does not exceed N pixels, e.g., 1 pixel.

[0196] The following two methods can be used to constrain the motion vectors to within a particular bit width.

[0197] Method 1: The overflow most significant bit of the motion vector is removed:

number

[0198] vx represents the horizontal component of the motion vector of the image block or sub-block of the image block, vy represents the vertical component of the motion vector of the image block or sub-block of the image block, ux and uy represent intermediate values, and bitDepth represents the bit width.

[0199] For example, the value of vx is -32769, and 32767 is derived according to the formula above. Values ​​are stored in a computer in two's complement notation, and the two's complement representation of -32769 is 1, 0111, 1111, 1111, 1111 (17 bits), and the processing performed by the computer discards the most significant bits due to overflow. Therefore, the value of vx is 0111, 1111, 1111, 1111, or 32767. This value matches the result derived by processing according to the formula.

[0200] Method 2: Clipping is performed on the motion vectors as shown in the following equation:

number

[0201] vx represents the horizontal component of the motion vector of the image block or a sub-block of the image block; vy represents the vertical component of the motion vector of the image block or a sub-block of the image block; x, y, and z correspond to the three input values ​​of the MV clamping process clip3; and clip3 is defined to indicate clipping the value of z to the range [x, y].

number

[0202] 4 is a schematic structural diagram of a video coding device 400 (e.g., video encoding device 400 or video decoding device 400) according to one embodiment of the present application. Video coding device 400 is suitable for implementing embodiments described herein. In one embodiment, video coding device 400 may be a video decoder (e.g., decoder 30 of FIG. 1A) or a video encoder (e.g., encoder 20 of FIG. 1A). In another embodiment, video coding device 400 may be one or more components of decoder 30 of FIG. 1A or encoder 20 of FIG. 1A.

[0203] The video coding device 400 includes an input port 410 and a receiver unit (Rx) 420 configured to receive data, a processor, logic unit, or central processing unit (CPU) 430 configured to process the data, a transmitter unit (Tx) 440 and an output port 450 configured to transmit the data, and a memory 460 configured to store the data. The video coding device 400 may further include optical-to-electrical and electrical-to-optical (EO) components coupled to the input port 410, the receiver unit 420, the transmitter unit 440, and the output port 450 for inputting or outputting optical or electrical signals.

[0204] The processor 430 is implemented by hardware and software. The processor 430 may be implemented as one or more CPU chips, cores (e.g., multi-core processors), FPGAs, ASICs, and DSPs. The processor 430 communicates with the input port 410, the receiver unit 420, the transmitter unit 440, the output port 450, and the memory 460. The processor 430 includes a coding module 470 (e.g., the encoding module 470 or the decoding module 470). The encoding / decoding module 470 implements the embodiments disclosed herein and implements the chroma block prediction method provided in the embodiments of the present application. For example, the encoding / decoding module 470 performs, processes, or provides various coding operations. Therefore, the inclusion of the encoding / decoding module 470 provides substantial improvements in the functionality of the video coding device 400 and affects the switching of the video coding device 400 to different states. Alternatively, the encoding / decoding module 470 is implemented as instructions stored in the memory 460 and executed by the processor 430 .

[0205] Memory 460 may include one or more disks, tape drives, and solid state drives, and may be used as overflow data storage, to store programs when such programs are selectively executed, and to store instructions and data read during program execution. Memory 460 may be volatile and / or non-volatile, and may be read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and / or static random access memory (SRAM).

[0206] FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 of FIG. 1A according to an exemplary embodiment. The apparatus 500 can implement the techniques of the present application. In other words, FIG. 5 is a schematic block diagram of an implementation of an encoding or decoding apparatus (coding apparatus 500 for short) according to an embodiment of the present application. The coding apparatus 500 can include a processor 510, a memory 530, and a bus system 550. The processor and the memory are connected via the bus system. The memory is configured to store instructions. The processor is configured to execute the instructions stored in the memory. The memory of the coding apparatus stores program code, and the processor can invoke the program code stored in the memory to perform various video encoding or decoding methods, particularly various novel decoding methods, described herein. To avoid repetition, details will not be described here.

[0207] In this embodiment of the present application, processor 510 may be a Central Processing Unit (abbreviated "CPU"), or processor 510 may be another general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPBGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. The general-purpose processor may be a microprocessor, or any conventional processor, etc.

[0208] Memory 530 may include a read-only memory (ROM) device or a random-access memory (RAM) device. Any other suitable type of storage device may alternatively be used as memory 530. Memory 530 may include code and data 531 accessed by processor 510 via bus 550. Memory 530 may further include an operating system 533 and application programs 535. Application programs 535 include at least one program that enables processor 510 to perform the video encoding or decoding methods described herein (particularly the decoding methods described herein). For example, application programs 535 may include applications 1-N, and further include a video encoding or decoding application (video coding application for short) used to perform the video encoding or decoding methods described herein.

[0209] The bus system 550 may include not only a data bus, but also a power bus, a control bus, a status signal bus, etc. However, for clarity of explanation, the various types of buses in the figures are marked as the bus system 550.

[0210] Optionally, coding apparatus 500 may further include one or more output devices, such as a display 570. In one example, display 570 may be a touch-sensitive display that combines a display with touch-sensitive elements that operatively sense touch input. Display 570 may be connected to processor 510 via bus 550.

[0211] The solution in the embodiment of the present application will be described in detail below.

[0212] In video coding standards, an image frame is partitioned into non-overlapping coding tree units (CTUs). The size of a CTU may be set to 64x64 (alternatively, the size of a CTU may be increased to another value, for example, 128x128 or 256x256). A 64x64 CTU is a rectangular pixel matrix with 64 rows, each row containing 64 pixels, and each pixel containing a luma component and / or a chroma component. A CTU represents a coding tree unit. An image includes multiple CTUs, and a CTU generally corresponds to a square image area and contains luma and chroma pixels in the image area (or may contain only luma pixels, or may contain only chroma pixels). A CTU further includes syntax elements. These syntax elements indicate how to divide the CTU into at least one coding unit (CU) and how to decode each coding unit to obtain a reconstructed image.

[0213] CU represents a coding unit. A CU generally corresponds to an A×B rectangular region and includes A×B luma pixels and chroma pixels corresponding to the A×B luma pixels. A represents the width of the rectangle, and B represents the height of the rectangle, where A and B may be the same or different. The values ​​of A and B are generally squares of integers, e.g., 256, 128, 64, 32, 16, 8, and 4. A decoding process can be performed on the coding unit to obtain a reconstructed image of the A×B rectangular region. The decoding process generally includes processes such as prediction, dequantization, and inverse transform to generate a predicted image and a residual. The predicted image and the residual are added to obtain a reconstructed image.

[0214] A quad-tree (QT) is a tree structure. One node can be divided into four child nodes. Video coding standards use a quad-tree-based CTU partitioning mode. The CTU serves as the root node, and each node corresponds to a square region. Specifically, the square region is divided into four square regions of the same size (the length and width of the resulting square region are half the length and width of the region before division, respectively). As shown in Figure 6(a), each region corresponds to one node. In some cases, a node cannot be further divided (in which case the region corresponding to the node is a CU), or the node is further divided into lower-level nodes by QT, BT, TT, or EQT.

[0215] A binary tree (BT) is a tree structure. A node can be split into two child nodes. The split into two child nodes can be performed in one of two ways: (1) horizontal binary tree splitting: As shown in Figure 6(b), the region corresponding to the node is split into two regions (upper and lower regions) of the same size, each corresponding to one node; or (2) vertical binary tree splitting: As shown in Figure 6(c), the region corresponding to the node is split into two regions (left and right regions) of the same size, each corresponding to one node. In the binary tree splitting coding method, a node in the binary tree structure may not be split (in which case the region corresponding to the node is a CU), or the node may be further split into lower-level nodes by BT, TT, or EQT.

[0216] A triple-tree (TT) is a tree structure. A node can be divided into three child nodes. In existing triple-tree-based coding methods, a node in a triple-tree structure may not be divided, or the node may be divided into three lower-level nodes. The division into three nodes can be performed in one of two ways: (1) horizontal triple-tree division: As shown in Figure 6(d), the region corresponding to a node is divided into three regions (top, middle, and bottom regions), each corresponding to a node, and the heights of the three regions are 1 / 4, 1 / 2, and 1 / 4 of the node height, respectively; or (2) vertical triple-tree division: As shown in Figure 6(e), the region corresponding to a node is divided into three regions (left, middle, and right regions), each corresponding to a node, and the widths of the three regions are 1 / 4, 1 / 2, and 1 / 4 of the node height, respectively. In the ternary tree split coding method, a node in the ternary tree structure may not be split (in which case the region corresponding to that node is a CU), or the node may be further split into lower level nodes by BT, TT, or EQT.

[0217] An extended quad-tree (EQT) is an "I"-shaped partitioning structure. One node can be partitioned into four child nodes. The partitioning into three nodes can be done in two ways: (1) horizontal quad-tree partitioning: As shown in Figure 6(f), the region corresponding to a node is partitioned into three regions (top region, middle region, and bottom region). Each region corresponds to one node. The heights of the top region, left middle region, right middle region, and bottom region are 1 / 4, 1 / 2, 1 / 2, and 1 / 4 of the node height, respectively. The widths of the left middle region and right middle region are 1 / 2 and 1 / 2 of the node height, respectively. or (2) vertical quadtree division: as shown in Figure 6(g), the region corresponding to a node is divided into three regions (left region, upper middle region, lower middle region, and right region), each corresponding to one node, and the widths of the left region, middle region, and right region are 1 / 4, 1 / 2, 1 / 2, and 1 / 4 of the node height, respectively, and the widths of the upper middle region and lower middle region are 1 / 2 and 1 / 2 of the node height, respectively. In the extended quadtree coding method, it may not be possible to divide a node in the extended quadtree structure, or the node may be further divided into lower-level nodes by BT, TT, or EQT.

[0218] Video decoding is the process of recovering a video bitstream into a reconstructed image according to specific syntax rules and processing methods.

[0219] Video encoding is the process of compressing a sequence of images into a bitstream.

[0220] Video coding is a general term for video encoding and video decoding. The Chinese translation of video coding is the same as the Chinese translation of video encoding.

[0221] VTM is a new codec reference software developed by JVET.

[0222] In video coding standards, an image frame is partitioned into non-overlapping coding tree units (CTUs). The size of a CTU may be set to 64x64 (alternatively, the size of a CTU may be set to another value, for example, the size of a CTU may be increased to 128x128 or 256x256). A 64x64 CTU is a rectangular pixel matrix with 64 rows, each row containing 64 pixels, and each pixel containing a luma component or / and a chroma component.

[0223] A quad-tree (QT)-based CTU splitting method is used, where the CTU serves as the root node of the quad-tree and is recursively split into several leaf nodes in the quad-tree splitting mode. One node corresponds to one image region. If a node is not split, it is called a leaf node, and the image region corresponding to the node forms one CU. If the node is further split, the image region corresponding to the node is split into four regions of the same size (the lengths and widths of the four regions are half of the length and width of the region before splitting, respectively), and each region corresponds to one node. Whether these nodes are further split must be determined individually. Whether a node is further split is indicated by the split flag split_cu_flag in the bitstream and corresponding to the node. The quad-tree depth (qtDepth) of the root node is 0, and the quad-tree depth of a child node is the quad-tree depth of its parent node plus 1. For simplicity, in the following, the size and shape of a node is the size and shape of the image region corresponding to the node.

[0224] More specifically, for a 64x64 CTU node (quadtree depth is 0), the 64x64 CTU node cannot be split based on the split_cu_flag corresponding to the 64x64 CTU node, and the CTU node forms one 64x64 CU; or the 64x64 CTU node is split into four 32x32 nodes (quadtree depth is 1). Each of the four 32x32 nodes may or may not be further split based on the split_cu_flag corresponding to the node. Further splitting one 32x32 node generates four 16x16 nodes (quadtree depth is 2). By analogy, the splitting continues until all nodes cannot be further split, and such a CTU is divided into a group of CUs. The minimum size of a CU is identified in the SPS, for example, 8x8 represents the minimum size of a CU. In the recursive splitting process described above, if the size of a node is equal to the minimum CU size, by default the node will not be split any further and there is no need to include the split flag of the node in the bitstream.

[0225] After parsing finds that a node is a leaf node, the leaf node is a CU, and coding information corresponding to the CU (e.g., information such as the prediction mode and transform coefficients of the CU, including, for example, the coding_unit() syntax structure) is further analyzed. Then, based on the coding information, decoding processes such as prediction, dequantization, inverse transform, and loop filtering are performed on the CU to generate a reconstructed image corresponding to the CU. The CTU can be divided into groups of CUs with appropriate sizes based on local image features using a quadtree structure. For example, smooth regions are divided into larger CUs, and texture-rich regions are divided into smaller CUs.

[0226] The partitioning mode by which a CTU is partitioned into groups of CUs corresponds to a coding tree. The specific coding tree to be used for a CTU is usually determined based on the encoder's rate distortion optimization (RDO) technique. The encoder attempts to use multiple CTU partitioning modes, with each partitioning mode corresponding to a rate distortion cost (RD cost). The encoder compares the RD costs of the various partitioning modes that were attempted and uses the partitioning mode with the smallest RD cost as the optimal partitioning mode for the CTU for the actual coding of the CTU. The CTU partitioning mode that the encoder attempts to use must comply with the partitioning rules specified by the decoder so that the decoder can correctly identify the CTU partitioning mode.

[0227] In screen content video, images usually contain the same content. For example, in an image containing numbers or graphics, the same numbers or graphics may be found around the current block, as shown in FIG. 7. Therefore, if a referenceable block is found around the current block during coding of the current block, the reconstructed pixels of that block are directly referenced. In this way, the coding compression rate is significantly improved. Intra Block Copy (IBC) technology is an intra prediction technology used to search for the same block in the current screen content. For example, the syntax element pred_mode_ibc_flag in Table 2 can be used to indicate whether the IBC prediction mode is used for the current coding unit.

[0228] Based on the quad-tree division, a binary-tree (abbreviated as BT) division mode and an extended quad-tree (abbreviated as EQT) division mode can further be used.

[0229] A node is split into two child nodes by a binary tree split. Specifically, there are two binary tree split modes: (1) Horizontal binary tree partitioning: As shown in Figure 6(b), the region corresponding to a node is divided into two regions with the same size (i.e., the width remains unchanged, and the height is half the height of the region before the partitioning), and each region corresponds to one node; and (2) Vertical binary tree division: As shown in Figure 6(c), the region corresponding to the node is divided into two regions (left region and right region) of the same size (i.e., the height remains unchanged and the width is half the width of the region before division).

[0230] A node is split into four child nodes by extended quadtree splitting. Specifically, there are two extended quadtree splitting modes: (1) Horizontal quadtree division: As shown in Figure 6(f), the region corresponding to a node is divided into three regions (top region, middle region, and bottom region), each corresponding to one node. The heights of the top region, left middle region, right middle region, and bottom region are 1 / 4, 1 / 2, 1 / 2, and 1 / 4 of the node height, respectively. The widths of the left middle region and right middle region are 1 / 2 and 1 / 2 of the node height, respectively. (2) Vertical quadtree division: As shown in Figure 6(g), the region corresponding to a node is divided into three regions (left region, upper middle region, lower middle region, and right region), each corresponding to one node. The widths of the left region, middle region, and right region are 1 / 4, 1 / 2, 1 / 2, and 1 / 4 of the node height, respectively. The widths of the upper middle region and the lower middle region are 1 / 2 and 1 / 2 of the node height, respectively.

[0231] The QT plus BT / EQT split mode means that a node in a first-level coding tree can be split into child nodes only by QT, a leaf node in the first-level coding tree is a root node of a second-level coding tree, a node in the second-level coding tree can be split into child nodes by BT or EQT, and a leaf node in the second-level coding tree is a coding unit. It should be noted that when the BT or EQT split mode is used for a leaf node, only the BT or EQT split mode is used for the leaf node, and the QT split mode is not allowed to be used for the leaf node.

[0232] Alternatively, based on the quad-tree division, a binary-tree (abbreviated as BT) division mode and a triple-tree (abbreviated as TT) division mode can be further used.

[0233] A node is split into two child nodes by a binary tree split. Specifically, there are two binary tree split modes: (1) Horizontal binary tree partitioning: As shown in Figure 6(b), the region corresponding to a node is divided into two regions with the same size (i.e., the width remains unchanged, and the height is half the height of the region before the partitioning), and each region corresponds to one node; and (2) Vertical binary tree division: As shown in Figure 6(c), the region corresponding to the node is divided into two regions (left region and right region) of the same size (i.e., the height remains unchanged and the width is half the width of the region before division).

[0234] A node is split into two child nodes by a ternary tree split. Specifically, there are two binary tree split modes: (1) Horizontal ternary tree division: As shown in Figure 6(d), the region corresponding to a node is divided into three regions (upper region, middle region, and lower region), each corresponding to one node, and the heights of the upper region, middle region, and lower region are 1 / 4, 1 / 2, and 1 / 4 of the height of the node, respectively; and (2) Vertical ternary tree division: As shown in Figure 6(e), the region corresponding to a node is divided into three regions (left region, middle region, and right region), each corresponding to one node, and the widths of the left region, middle region, and right region are 1 / 4, 1 / 2, and 1 / 4 of the node height, respectively.

[0235] The QT plus BT / TT splitting mode, briefly called QT-BTT, means that a node in the first-level coding tree can be split into child nodes by QT only, a leaf node in the first-level coding tree is the root node of the second-level coding tree, a node in the second-level coding tree can be split into child nodes by one of four splitting modes (horizontal binary tree split, vertical binary tree split, horizontal ternary tree split, vertical ternary tree split), and a leaf node in the second-level coding tree is a coding unit.

[0236] A portion of the CU-level syntax structure may be shown in Table 1. If the current node is not further divided into child nodes, the current node is a coding unit, and the predictive blocks of the coding unit are parsed based on the following syntax structure.

[0237] skip_flag represents a flag for skip mode. When the value of skip_flag is 1, it indicates that skip mode is used for the current CU, or when the value of skip_flag is 0, it indicates that skip mode is not used for the current CU.

[0238] merge_flag represents a flag for direct mode. When the value of merge_flag is 1, it indicates that merge mode is used for the current CU, or when the value of merge_flag is 0, it indicates that merge mode is not used for the current CU.

[0239] cu_pred_mode represents the prediction mode flag of the coding unit. When the value of cu_pred_mode is 1, it indicates that an intra prediction mode is used for the current prediction unit, or when the value of cu_pred_mode is 0, it indicates that a common inter prediction mode is used for the current prediction unit. [Table 1]

[0240] A portion of the CU level syntax structure may alternatively be shown in Table 2. Table 2 is merely an example. The meaning of cu_skip_flag in Table 2 is the same as the meaning of skip_flag in Table 1, and the meaning of pred_mode_flag in Table 2 is the same as the meaning of cu_pred_mode in Table 1.

[0241] cu_skip_flag represents a flag for skip mode. When the value of cu_skip_flag is 1, it indicates that skip mode is used for the current CU, or when the value of cu_skip_flag is 0, it indicates that skip mode is not used for the current CU.

[0242] general_merge_flag represents a flag for the merge mode. When the value of general_merge_flag is 1, it indicates that the merge mode is used for the current CU, or when the value of general_merge_flag is 0, it indicates that the merge mode is not used for the current CU.

[0243] pred_mode_flag represents the prediction mode flag of the coding unit. When the value of pred_mode_flag is 1, it indicates that an intra prediction mode is used for the current coding unit, or when the value of pred_mode_flag is 0, it indicates that a common inter prediction mode is used for the current coding unit. When the value of pred_mode_flag is 1, CuPredMode[x0][y0] is MODE_INTRA. When the value of pred_mode_flag is 0, CuPredMode[x0][y0] is MODE_INTER.

[0244] If the value of pred_mode_ibc_flag is 1, it indicates that the IBC prediction mode is used for the current coding unit, or if the value of pred_mode_ibc_flag is 0, it indicates that the IBC prediction mode is not used for the current coding unit. If the value of pred_mode_ibc_flag is 1, CuPredMode[x0][y0] is MODE_IBC.

[0245] CuPredMode [x0][y0] represents the prediction mode of the current coding unit, and (x0, y0) represents the position of the current coding unit in the current image. [Table 2-1] [Table 2-2]

[0246] Dividing a node having a size of 8×M (or M×8) by vertical binary tree division (or horizontal binary tree division) generates two child nodes each having a size of 4×M (or M×4). Similarly, dividing a node having a size of 16×M (or M×16) by vertical extended quad tree division (or horizontal extended quad tree division) generates four child nodes each having a size of 4×M (or M×4) and one child node having a size of 8×M (or N×8). Similarly, dividing a node having a size of 16×M (or M×16) by vertical ternary tree division (or horizontal ternary tree division) generates two child nodes each having a size of 4×M (or M×4) and one child node having a size of 8×M (or N×8). In the case of the YUV4:2:0 data format, the resolution of the chroma components is half that of the luma component. In other words, one 4×M node includes one 4×M luma block and two 2×(M / 2) chroma blocks. For a hardware decoder, the cost of processing small blocks (especially small blocks with a size of 2×2, 2×4, or 2×8) is relatively high. However, small blocks with a size of 2×2 or 2×4 are generated in such a division mode. This is disadvantageous for the implementation of a hardware decoder. It is relatively complex for a hardware decoder to process small blocks. The complexity is particularly reflected in the following three aspects:

[0247] (1) Intra prediction: To increase processing speed, hardware is generally designed to process 16 pixels at a time during intra prediction. However, small blocks with sizes such as 2x2, 2x4, or 4x2 contain fewer than 16 pixels. As a result, the processing performance of intra prediction decreases.

[0248] (2) Coefficient Coding: In HEVC, transform coefficient coding is performed based on a coefficient group (CG) containing 16 coefficients. However, small blocks with sizes such as 2x2, 2x4, or 4x2 contain four or eight transform coefficients. As a result, to support coefficient coding of these small blocks, coefficient groups containing four or eight coefficients must be added, which increases the implementation complexity.

[0249] (3) Inter-prediction: Small block inter-prediction has a relatively high requirement on data bandwidth, which affects the decoding speed.

[0250] When a child node includes a chroma block whose side length is 2 and is generated by further dividing the node in the division mode, the luma block included in the child node is further divided in the division mode, and the chroma block included in the child node is not further divided. In this way, a chroma block whose side length is 2 is not generated. This reduces the maximum throughput rate of the decoder, which is advantageous for decoder implementation. Furthermore, a method for determining a chroma block prediction mode based on a luma block prediction mode is provided, thereby effectively improving coding efficiency.

[0251] The image prediction method provided herein may be used in the video encoder 18 or the video decoder 24 shown in Figure 8. Please note that one or more steps in some of the following embodiments are performed only in the video decoder 24, and are specifically described in the corresponding sections below.

[0252] In the following, the image prediction method in the present application will be described in detail using specific embodiments. It should be noted that the following specific embodiments can be combined with each other, and the same or similar content will not be repeatedly described in different embodiments.

[0253] 9 is a schematic flowchart of a first image prediction method according to an embodiment of the present application. Referring to FIG. 9, the image prediction method provided in this embodiment includes the following steps:

[0254] Step 101: Obtain the split mode of the current node.

[0255] In this embodiment, the splitting information of the current node is first analyzed, and the splitting information is used to indicate whether to split the current node or not. If the splitting information indicates to split the current node, the splitting mode of the current node is obtained. The splitting mode of the current node includes at least one of quadtree splitting, vertical binary tree splitting, horizontal binary tree splitting, vertical ternary tree splitting, and horizontal ternary tree splitting. Of course, there may be other splitting modes, which are not particularly limited in this embodiment.

[0256] The partitioning information of the current node may be transmitted in the bitstream. The partitioning information of the current node may be parsed from a corresponding syntax element in the bitstream, and a specific partitioning mode may be determined. Alternatively, the partitioning mode of the current node may be determined according to another preset rule, which is not particularly limited in this embodiment.

[0257] In this embodiment, when the partition information related to the current node and obtained by parsing is used to indicate that the current node is to be partitioned, the partition information specifically includes the partition mode of the luma blocks included in the current node and / or the partition mode of the chroma blocks included in the current node. The partition mode of the luma blocks included in the current node may be the same as or different from the partition mode of the chroma blocks included in the current node. This is not particularly limited in this embodiment. For example, the partition information is used to indicate that quadtree partitioning is used for both the luma blocks and the chroma blocks of the current node. Alternatively, the partition information is used to indicate that quadtree partitioning is used for the luma blocks of the current node and vertical binary tree partitioning is used for the chroma blocks of the current node.

[0258] Step 102: Determine whether an image block with a preset size is obtained by dividing the current node in the division mode.

[0259] The image block having a preset size may be a luma block having a size less than a threshold value, which may be a number of luma samples such as 128, 64, or 32, or a number of chroma samples such as 32, 16, or 8. The size of the current node may be greater than or equal to the threshold value.

[0260] If it is determined that an image block having a preset size is obtained by dividing the current node in the division mode, step 103 is executed. If it is determined that an image block having a preset size is not obtained by dividing the current node in the division mode, step 104 is executed.

[0261] Step 103: Perform intra prediction or inter prediction on all coding blocks covered by the current node.

[0262] It should be noted that the current node in this embodiment can be understood as an image region or image block corresponding to the node to be processed or the node to be split. All coding blocks covered by the current node can be understood as all coding blocks located in the region corresponding to the current node. All coding blocks in this embodiment include luma coding blocks and chroma coding blocks obtained by splitting or not splitting the current node. Alternatively, a coding block can be a coding unit.

[0263] Optionally, the intra prediction performed can be in a general intra prediction mode (intra mode) or in an IBC (intra block copy) mode.

[0264] Optionally, if the slice type in which the current node is located is of intra type, intra prediction is performed for all coding blocks covered by the current node instead of inter prediction.

[0265] In an embodiment, the step of performing intra prediction on all coding blocks covered by the current node comprises: In a split mode, the method may include the steps of: splitting a luma block included in the current node to obtain a luma block obtained by the split, and performing intra prediction on the luma block obtained by the split; and using a chroma block included in the current node as a chroma coding block and performing intra prediction on the chroma coding block.

[0266] In other words, if it is determined to perform intra prediction for all coding blocks of the current node, the luma block of the current node is split in the luma block split mode to obtain N luma coding tree nodes; and the chroma block of the current node is not split to obtain one chroma coding block (chroma CB for short).

[0267] The N luma coding tree nodes may be restricted to not being further split, or this is not restricted. If the luma coding tree node is further split, the splitting mode of the luma coding tree node is analyzed for recursive splitting. If the luma coding tree node is not further split, the luma coding tree node corresponds to one luma coding block (luma CB for short). Intra prediction is performed on the luma CB to obtain a luma prediction block corresponding to the luma CB.

[0268] Intra prediction is performed on the chroma CB to obtain a chroma prediction block corresponding to the chroma CB, where the chroma prediction block and the chroma CB have the same size.

[0269] In an embodiment, the step of performing inter prediction on all coding blocks covered by the current node comprises: In a split mode, the method may include the steps of: splitting a luma block included in the current node to obtain a luma block obtained by the split, and performing inter prediction on the luma block obtained by the split; and using a chroma block included in the current node as a chroma coding block, and performing inter prediction on the chroma coding block.

[0270] In other words, if it is determined to perform inter prediction for all coding blocks of the current node, the luma block of the current node is split in the luma block split mode to obtain N luma coding tree nodes; and the chroma block of the current node is not split to obtain one chroma coding block (chroma CB for short).

[0271] In this embodiment, when it is determined to perform intra prediction on all coding blocks of the current node, or when it is determined to perform inter prediction on all coding blocks of the current node, the luma blocks included in the current node are split in the split mode of the current node, and the chroma blocks of the current node are not split any further. According to the above method, small chroma blocks on which intra prediction is performed are not generated, and therefore, cases in which intra prediction is performed on small chroma blocks are avoided.

[0272] In an embodiment, the step of performing inter prediction on all coding blocks covered by the current node comprises: The method may include the steps of: in a split mode, splitting a luma block included in the current node to obtain a luma block obtained by the splitting, and performing inter prediction on the luma block obtained by the splitting; and in a split mode, splitting a chroma block included in the current node to obtain a chroma block obtained by the splitting, and performing inter prediction on the chroma block obtained by the splitting.

[0273] In other words, when it is determined to perform inter prediction on all coding blocks of the current node, the luma block of the current node is divided in a luma block division mode to obtain N luma coding tree nodes; and the chroma block of the current node is divided in a chroma block division mode to obtain M chroma coding tree nodes. N and M are positive integers, and N and M may be the same or different. The N luma coding tree nodes and the M chroma coding tree nodes may or may not be restricted to not being further divided. When no further division is performed, the N luma coding tree nodes correspond to the N luma CBs of the current node, and the M chroma coding tree nodes correspond to the M chroma CBs of the current node. Inter prediction is performed on the N luma CBs to obtain corresponding luma prediction blocks, and inter prediction is performed on the M chroma CBs to obtain corresponding chroma prediction blocks.

[0274] Optionally, when performing inter prediction for all coding blocks covered by the current node, performing inter prediction for all coding blocks covered by the current node comprises: The method may include: obtaining a partitioning submode of a child node of the current node, the child node including a luma block and a chroma block; determining whether a luma block having a first predetermined size is obtained by partitioning the child node of the current node in the partitioning submode; and, if it is determined that a luma block having the first predetermined size is obtained by partitioning the child node of the current node in the partitioning submode, partitioning the child node of the current node in a partitioning mode other than the partitioning submode to obtain a corresponding coding block and performing inter prediction on the corresponding coding block; or using the child node of the current node as a coding block and performing inter prediction on the child node of the current node.

[0275] In other words, if a luma block having a first preset size (4x4) is generated by dividing a child node of the current node in the division submode, the division submode of the child node is not permitted, or further division of the child node is not permitted, or the child node is divided in a division mode other than the division submode. For example, if the size of the current node is 8x8 and two 8x4 (or 4x8) nodes are generated by horizontal binary tree division (or vertical binary tree division), further division of the 8x4 (or 4x8) node generates a 4x4 block. In this case, further division of the 8x4 (or 4x8) node is not permitted.

[0276] Step 104: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0277] Specifically, the luma block of the current node is split with the partition mode of the luma block of the current node, and the chroma block of the current node is split with the partition mode of the chroma block of the current node.

[0278] Please note that step 104, "The prediction modes used for all coding blocks covered by the current node are not restricted" can be understood as follows: all coding blocks covered by the current node may not be predicted with the same prediction mode, i.e., the prediction mode of each coding block is analyzed, and each coding block is predicted with the prediction mode obtained by the analysis.

[0279] Optionally, after step 103 or step 104, the method further includes:

[0280] Step 105: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0281] Step 106: Decode each coding block to obtain a reconstructed signal of the image block corresponding to the current node.

[0282] It should be noted that the above two steps may be used in the video decoder 24 shown in FIG.

[0283] The prediction block includes a prediction mode (indicating an intra prediction mode or a non-intra prediction mode), an intra prediction mode, an inter prediction mode, motion information, etc. The motion information may include information such as a prediction direction (forward, backward, or bidirectional), a reference frame index, and a motion vector.

[0284] The residual information includes coded block flags (cbf), transform coefficients, transform type (DCT-2, DCT-7, or DCT-8, etc.), etc. The transform type may be DCT-2 by default.

[0285] When the current node is restricted to performing only intra prediction for all coding blocks covered by the current node, analyzing the prediction block of the luma CB obtained by splitting the current node includes: setting the values ​​of skip_flag, merge_flag, and cu_pred_mode to 0, 0, and 1 by default (i.e., skip_flag, merge_flag, and cu_pred_mode are all absent in the bitstream), or setting the values ​​of skip_flag and cu_pred_mode to 0 and 1 by default (i.e., skip_flag and cu_pred_mode are both absent in the bitstream); and analyzing information about the intra prediction mode of the luma CB. Analyzing the prediction block of the chroma CB obtained by splitting the current node includes analyzing the intra prediction mode of the chroma CB. The intra prediction mode of chroma CB can be analyzed according to the following methods: (1) analyzing syntax elements in the bitstream to obtain the intra prediction mode; or (2) directly setting the intra prediction mode to one intra prediction mode in a set of chroma intra prediction modes, such as linear model mode, DM mode (chroma derived mode), IBC mode, etc.

[0286] When the current node is restricted to performing only inter prediction for all coding blocks covered by the current node, the step of analyzing the prediction mode of the CU obtained by splitting the current node includes the steps of analyzing skip_flag and / or merge_flag, setting the value of cu_pred_mode to 0 by default, and analyzing inter prediction blocks such as merge index, inter direction, reference index, motion vector predictor index, and motion vector difference.

[0287] skip_flag is a flag for skip mode. When the value of skip_flag is 1, it indicates that skip mode is used for the current CU, or when the value of skip_flag is 0, it indicates that skip mode is not used for the current CU. merge_flag is a flag for merge mode. When the value of merge_flag is 1, it indicates that merge mode is used for the current CU, or when the value of merge_flag is 0, it indicates that merge mode is not used for the current CU. cu_pred_mode represents a prediction mode flag for the coding unit. When the value of cu_pred_mode is 1, it indicates that intra prediction is performed for the current prediction unit, or when the value of cu_pred_mode is 0, it indicates that common inter prediction (which identifies information such as the inter direction in the bitstream, reference index, motion vector predictor index, and motion vector difference) is performed for the current prediction unit.

[0288] Optionally, when the current node is restricted to perform only inter prediction for all coding blocks covered by the current node, the step of analyzing the prediction block of the luma CB obtained by splitting the current node includes the steps of analyzing skip_flag and / or merge_flag, setting the value cu_pred_mode to 0 by default, and analyzing the inter prediction block, such as a merge index, an inter direction, a reference index, a motion vector predictor index, and a motion vector difference. Motion information of each 4x4 sub-block in the luma CB is derived based on the inter prediction block obtained by the analysis. When the current node is restricted to perform only inter prediction for all coding blocks covered by the current node, it is not necessary to analyze the prediction block of the chroma CB obtained by splitting the current node. The chroma CB is split into 2x2 chroma sub-blocks (the split mode can be split mode S). The motion information of each 2x2 chroma sub-block is the motion information of the 4x4 luma region corresponding to the 2x2 chroma sub-block. In the aforementioned split mode, small chroma blocks on which intra prediction is performed are not generated, and transform blocks with a size less than 16 pixels are not generated, thus overcoming the aforementioned problems of inter prediction and coefficient coding.

[0289] Optionally, when the current node is restricted to perform only inter prediction for all coding blocks covered by the current node, there is no need to analyze the prediction block of the chroma CB obtained by splitting the current node. The chroma prediction block and the chroma coding block have the same size. The motion information of the chroma CB is the motion information of a predetermined position of the luma region corresponding to the chroma CB (e.g., the middle, the bottom right corner, or the top left corner of the luma region). In the above split mode, no small chroma blocks on which intra prediction is performed are generated, no small transform blocks are generated, and no small chroma blocks on which inter prediction is performed are generated.

[0290] It should be noted that in this embodiment, the intra prediction mode is a prediction mode in which a predictor of a coding block is generated using spatial domain reference pixels of an image in which the coding block is located. For example, the intra prediction mode is a direct current mode (DC mode), a planar mode, an angular mode, a template matching mode, or an IBC mode. The inter prediction mode is a prediction mode in which a predictor of a coding block is generated using temporal domain reference pixels of a reference image of the coding block. For example, the inter prediction mode is a skip mode, a merge mode, or an advanced motion vector prediction (AMVP) mode (also called a common inter mode).

[0291] Based on the predicted block of the coding block, inter prediction or intra prediction is performed on each coding block to obtain an inter predicted image or intra predicted image of the coding block, and then, based on the residual information of each coding block, dequantization and inverse transform operations are performed on the transform coefficients to obtain a residual image, and the residual image is added to the predicted image of the corresponding region to generate a reconstructed image.

[0292] Optionally, in a possible implementation, the image blocks having a preset size include luma blocks having a first preset size, and therefore step 102 may include: The method includes a step of determining whether a luma block having a first preset size is obtained by dividing the current node in a division mode of the luma block of the current node, and the luma block having the first preset size is a luma block having a pixel size of 4x4.

[0293] If a luma block having a first preset size is obtained by splitting the luma block of the current node in the split mode of the luma block of the current node, then step 103 includes performing intra prediction for all coding blocks covered by the current node.

[0294] If a luma block having the first preset size is not obtained by splitting the luma block of the current node in the partition mode of the luma block of the current node, then step 104 includes splitting the luma block of the current node in the partition mode of the luma block of the current node and splitting the chroma block of the current node in the partition mode of the chroma block of the current node, and the prediction modes used for all coding blocks covered by the current node are not restricted.

[0295] Optionally, in another possible implementation, the image block having the preset size includes a chroma block having a second preset size, and therefore step 102 may include: The method includes a step of determining whether a chroma block having a second preset size is obtained by dividing the current node in a chroma block division mode of the current node, and the chroma block having the second preset size is a chroma block having a pixel size of 2x2, 2x4, or 4x2.

[0296] If a chroma block having a second preset size is obtained by splitting the chroma block of the current node in the split mode of the chroma block of the current node, then step 103 includes performing intra prediction or inter prediction on all coding blocks covered by the current node.

[0297] If a chroma block having a second preset size is not obtained by splitting the chroma block of the current node in the split mode of the chroma block of the current node, then step 104 includes splitting the chroma block of the current node in the split mode of the chroma block of the current node and splitting the luma block of the current node in the split mode of the luma block of the current node, and the prediction modes used for all coding blocks covered by the current node are not restricted.

[0298] According to the image prediction method provided in this embodiment, a partition mode of a current node is obtained, and it is determined whether an image block having a preset size will be obtained by dividing the current node using the partition mode of the current node, where the image block includes a luma block or a chroma block. If an image block having a preset size will be obtained by dividing the current node using the partition mode of the current node, intra prediction or inter prediction is performed on all coding blocks covered by the current node. According to the above method, since intra prediction or inter prediction is performed on all coding blocks of the current node, parallel processing can be performed on all coding blocks of the current node. This improves the processing performance of image prediction and increases the coding processing speed.

[0299] 9, a process of determining whether a luma block having a first preset size is obtained by dividing a current node in a division mode of a luma block of the current node according to an image prediction method provided in the following embodiments is described in detail. A set of conditions for determining whether a luma block having a first preset size is obtained is specifically disclosed.

[0300] 10 is a schematic flowchart of a second image prediction method according to an embodiment of the present application. As shown in FIG. 10, the image prediction method provided in this embodiment includes the following steps:

[0301] Step 201: Obtain the split mode of the current node.

[0302] Specifically, the partitioning information of the current node is analyzed. If the partitioning information indicates that the luma block of the current node is to be partitioned, a partitioning mode of the luma block of the current node is further determined. The partitioning mode of the luma block includes at least one of quadtree partitioning, vertical binary tree partitioning, horizontal binary tree partitioning, vertical ternary tree partitioning, and horizontal ternary tree partitioning. Of course, there may be other partitioning modes, which are not particularly limited in this embodiment.

[0303] Step 202: Based on the size of the current node and the division mode of the current node, determine whether a luma block having a first preset size is obtained by dividing the current node in the division mode.

[0304] The luma block having the first preset size may be a luma block having a pixel size of 4x4 or 8x8.

[0305] If it is determined that a luma block having a first preset size is obtained by dividing the current node in the division mode, step 203 is executed. If it is determined that a luma block having a first preset size is not obtained by dividing the current node in the division mode, step 204 is executed.

[0306] Specifically, based on the size of the current node and the luma block division mode of the current node, it is determined whether a luma block having a first preset size can be obtained by dividing the current node in the luma block division mode.

[0307] In this embodiment, the size of the current node may be understood as the pixel size of the image block corresponding to the current node. The size of the current node may be determined based on the width and height of the image block corresponding to the current node, or may be determined based on the area of ​​the image block corresponding to the current node, or may be determined based on the number of luma pixels of the image block corresponding to the current node. For example, the current node including 128 luma pixels may describe that the area of ​​the current node is 128, and may describe that the product of the width and height of the current node is 128.

[0308] The step of determining, based on the size of the current node and the luma block partition mode of the current node, that a luma block having a first preset size is obtained by partitioning the current node in the luma block partition mode is performed based on one or more conditions of a first set of the following: (1) The current node contains M1 pixels, and the division mode of the current node is quadtree division, for example, M1 is 64; (2) The current node contains M2 pixels, and the division mode of the current node is ternary tree division, for example, M2 is 64; (3) The current node contains M3 pixels, and the division mode of the current node is binary tree division, e.g., M3 is 32; (4) The current node contains 64 luma pixels, and ternary tree partitioning (vertical ternary tree partitioning or horizontal ternary tree partitioning) or quadtree partitioning is used for the current node; or the current node contains 32 luma pixels, and binary tree partitioning (vertical binary tree partitioning or horizontal binary tree partitioning) is used for the current node; (5) The width of the current node is four times the second threshold, the height of the current node is equal to the second threshold, and the splitting mode of the current node is vertical ternary tree splitting; (6) The width of the current node is equal to the second threshold, the height of the current node is four times the second threshold, and the splitting mode of the current node is horizontal ternary tree splitting; (7) The width of the current node is twice the second threshold, the height of the current node is equal to the second threshold, and the splitting mode of the current node is vertical binary tree splitting; (8) The height of the current node is twice the second threshold, the width of the current node is equal to the second threshold, and the splitting mode of the current node is horizontal binary tree splitting; or (9) The width or / and height of the current node is twice the second threshold, and the partitioning mode of the current node is quadtree partitioning.

[0309] In the first set, the width of the current node is the width of the luma block corresponding to the current node, and the height of the current node is the height of the luma block corresponding to the current node. In a particular implementation, for example, the second threshold may be 4.

[0310] The first set above is applicable to YUV4:2:0 or YUV4:2:2 video data formats.

[0311] Optionally, when the luma block having the first preset size is a luma block having a pixel size of 4x4, determining whether a luma block having the first preset size is obtained by dividing the current node in a division mode based on the size of the current node and the division mode of the current node may be performed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is quadtree partitioning; (2) The number of samples in the luma block of the current node is 64, and the partitioning mode is ternary tree partitioning; or (3) The number of samples in the luma block of the current node is 32, and the partitioning mode is binary tree partitioning.

[0312] The number of samples in the luma block of the current node is the number of luma pixels (pixel size) of the image block corresponding to the current node.

[0313] Step 203: Perform intra prediction for all coding blocks covered by the current node.

[0314] In an alternative method of step 203, intra prediction may be performed only on coding blocks of the luma block having a first preset size, and the prediction modes of other coding blocks covered by the current node are not restricted.

[0315] The step of performing intra prediction on all coding blocks covered by the current node includes: In a split mode, the method may include the steps of: splitting a luma block included in the current node to obtain a luma block obtained by the split, and performing intra prediction on the luma block obtained by the split; and using a chroma block included in the current node as a chroma coding block and performing intra prediction on the chroma coding block.

[0316] In other words, if it is determined to perform intra prediction for all coding blocks of the current node, the luma block of the current node is split in the luma block split mode to obtain N luma coding tree nodes; and the chroma block of the current node is not split to obtain one chroma coding block (chroma CB for short).

[0317] The N luma coding tree nodes may be restricted to not be further split, or this is not restricted. If the luma coding tree node is further split, the split mode of the luma coding tree node is analyzed for recursive splitting. If the luma coding tree node is not further split, the luma coding tree node corresponds to one luma coding block (luma CB for short). Intra prediction is performed on the luma CB to obtain a luma prediction block corresponding to the luma CB.

[0318] Intra prediction is performed on the chroma CB to obtain a chroma prediction block corresponding to the chroma CB, where the chroma prediction block and the chroma CB have the same size.

[0319] Optionally, the step of performing intra prediction on all coding blocks covered by the current node comprises: The method may include: using a luma block included in the current node as a luma coding block and performing intra prediction on the luma coding block; and using a chroma block included in the current node as a chroma coding block and performing intra prediction on the chroma coding block. In other words, both the luma block and the chroma block of the current node cannot be further divided.

[0320] Step 204: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0321] Step 204 in this embodiment is the same as step 104 in the embodiment shown in Figure 9. For details, please refer to the previous embodiment, and the details will not be described again here.

[0322] Optionally, after step 203 or step 204, the method further includes:

[0323] Step 205: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0324] Step 206: Decode each coding block to obtain a reconstructed signal of the image block corresponding to the current node.

[0325] Step 205 and step 206 in this embodiment are the same as step 105 and step 106 in the embodiment shown in Figure 9. For details, please refer to the previous embodiment, and the details will not be described again here.

[0326] According to the image prediction method provided in this embodiment, a partition mode of a current node is obtained; whether a luma block having a first preset size is obtained by dividing the current node in the luma block partition mode is determined based on the size of the current node and the luma block partition mode; and if it is determined that a luma block having the first preset size is obtained by dividing the current node in the luma block partition mode, intra prediction is performed on all coding blocks covered by the current node. According to the above method, intra prediction is performed on all coding blocks of the current node, so that parallel processing can be performed on all coding blocks of the current node. This improves the processing performance of image prediction and increases the coding processing speed.

[0327]

[0047] Figure 11 is a schematic flowchart of a third image prediction method according to an embodiment of the present application. Based on the embodiment shown in Figure 10, it should be noted that the solution shown in Figure 11 can be used for a video data format of YUV4:2:0 or YUV4:2:2, or for a video data format of only YUV4:2:0, as shown in Figure 11. When it is determined that a luma block having a first preset size is not obtained by dividing the current node in the division mode, step 204 may include the following steps:

[0328] Step 2041: Determine whether a chroma block having a second preset size is obtained by dividing the current node in the division mode.

[0329] If it is determined that a chroma block having the second preset size is obtained by dividing the current node in the split mode, then step 2042 is executed. If it is determined that a chroma block having the second preset size is not obtained by dividing the current node in the split mode, then step 2043 is executed.

[0330] Specifically, step 2041 includes determining, based on the size of the current node and the chroma block division mode, whether a chroma block having a second preset size is obtained by dividing the current node according to the chroma block division mode. The chroma block having the second preset size may be a chroma block having a pixel size of 2x2, 2x4, or 4x2.

[0331] The step of determining, based on the size of the current node and the chroma block splitting mode, that a chroma block having a second preset size is obtained by splitting the current node in the chroma block splitting mode is performed based on one or more conditions of a second set of the following:

[0332] When the video data format is YUV4:2:2, the second set includes the following: (1) The size of the chroma block of at least one child node of the current node is 2×2, 2×4, or 4×2; (2) The width or height of the chroma block of at least one child node of the current node is 2; (3) The current node contains 64 luma pixels, and the splitting mode of the current node is a ternary split or a quadtree split; (4) The current node contains 32 luma pixels, and the splitting mode of the current node is a binary split or a ternary split; or (5) The area of the current node (i.e., the product of the width and the height) is S, where S / 2 < th1, and the splitting mode of the current node is a vertical binary split or a horizontal binary split; or, the area of the current node (i.e., the product of the width and the height) is S, where S / 4 < th1, and the splitting mode of the current node is a vertical ternary split, a horizontal ternary split, or a quadtree split. The threshold th1 is 32.

[0333] When the video data format is YUV4:2:0, the second set includes the following: (1) The size of the chroma block of at least one child node of the current node is 2×2, 2×4, or 4×2; (2) The width or height of the chroma block of at least one child node of the current node is 2; (3) The current node contains 128 luma pixels, and a ternary split is used for the current node; or, the current node contains 64 luma pixels, and a binary split, a quadtree split, or a ternary split is used for the current node; (4) The current node contains 256 luma pixels, and a ternary split or a quadtree split is used for the node; or, the current node contains 128 luma pixels, and a binary split is used for the node; (5) The current node contains N1 luma pixels, and a ternary split is used for the current node, where N1 is 64, 128, or 256; (6) The current node contains N2 luma pixels, and quadtree splitting is used for the current node, where N2 is 64 or 256; (7) The current node contains N3 luma pixels, and binary tree splitting is used for the current node, where N3 is 64, 128, or 256; or (8) The area of the current node (i.e., the product of width and height) is S, where S / 2 < th1, and the splitting mode of the current node is vertical binary tree splitting or horizontal binary tree splitting; or, the area of the current node (i.e., the product of width and height) is S, where S / 4 < th1, and the splitting mode of the current node is vertical ternary tree splitting, horizontal ternary tree splitting, or quadtree splitting. The threshold th1 is 64.

[0334] Optionally, the luma block having the first preset size may be a 4×4 luma block. When the luma block having the first preset size is a 4×4 luma block, the chroma block having the second preset size may be the pixel size of a 2×4 chroma block or the pixel size of a 4×2 chroma block (excluding 2×2 chroma blocks).

[0335] Optionally, the luma block having the first preset size may be a 4×4 luma block. When the luma block having the first preset size is a 4×4 luma block, the chroma block having the second preset size may be a 4×8 luma block or an 8×4 luma block (excluding 4×4 luma blocks).

[0336] Optionally, when the chroma block having the second preset size is a 2×4 chroma block, a 4×2 chroma block, a 4×8 luma block, or an 8×4 luma block, the step of determining whether the chroma block having the second preset size is obtained by splitting the current node in the splitting mode may be executed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (2) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0337] Step 2042: Perform intra prediction or inter prediction on all coding blocks covered by the current node.

[0338] Whether intra prediction or inter prediction is performed for all coding blocks covered by the current node may be determined according to the following method.

[0339] Method 1: Analyze the prediction mode status flag of the current node; if the value of the prediction mode status flag is a first value, perform inter prediction for all coding blocks covered by the current node; or if the value of the prediction mode status flag is a second value, perform intra prediction for all coding blocks covered by the current node.

[0340] In this method, the prediction mode used for all coding blocks covered by the current node is actually determined based on a flag in a syntax table. Specifically, a prediction mode status flag cons_pred_mode_flag is parsed from the bitstream. When the first value of cons_pred_mode_flag is set to 0, it indicates that inter prediction is performed on all coding blocks obtained by splitting or not splitting the current node, and when the second value of cons_pred_mode_flag is set to 1, it indicates that intra prediction is performed on all coding blocks obtained by splitting or not splitting the current node. Optionally, when the first value of cons_pred_mode_flag is set to 1, it indicates that inter prediction is performed on all coding blocks obtained by splitting or not splitting the current node, and when the second value of cons_pred_mode_flag is set to 0, it indicates that intra prediction is performed on all coding blocks obtained by splitting or not splitting the current node. The meaning of cons_pred_mode_flag may alternatively be indicated by another flag (e.g., mode_cons_flag), which is not limited in this embodiment.

[0341] cons_pred_mode_flag may be a syntax element that needs to be parsed during block division. When parsing the syntax element, the prediction mode flag cu_pred_mode of the coding unit of the coding unit in the coverage area of ​​the current node may not be parsed further, and the value of cu_pred_mode is a default value corresponding to the value of cons_pred_mode_flag.

[0342] The syntax element cons_pred_mode_flag is semantically described as follows: if the value of cons_pred_mode_flag is 0, it indicates that only inter prediction is performed for the coding units covered by the current node; or if the value of cons_pred_mode_flag is 1, it indicates that only intra prediction is performed for the coding blocks covered by the current node.

[0343] If the current node is located in an intra-picture region (i.e., the type or slice (slice_type) of the picture where the current node is located is intra-type or I-type) and the use of IBC mode is allowed, the value of cu_pred_mode is derived as 1, and the value of cu_pred_mode is obtained without the need to parse the bitstream. If the current node is located in an intra-picture region but the use of IBC mode is not allowed, the value of cu_pred_mode is derived as 1, the value of cu_skip_flag is 0, and the value of cu_pred_mode is obtained without the need to parse the bitstream.

[0344] If the current node is located in an inter-image region (i.e., the type or slice (slice_type) of the image where the current node is located is inter-type or B-type), the value of cu_pred_mode is derived as 0, and the value of cu_pred_mode is obtained without the need to parse the bitstream.

[0345] Because the reference pixels of IBC prediction are reconstructed pixels of the current image, IBC prediction mode can be considered as an intra prediction mode.Therefore, in this embodiment of the present application, intra prediction can include IBC mode.In other words, in this embodiment of the present application, IBC mode, common intra-intra prediction mode, or IBC mode + common intra-intra prediction mode can be used for intra prediction.Therefore, in this embodiment of the present application, intra prediction can be understood as non-inter prediction.

[0346] Optionally, the slice type in which the current node is located is not of the Intra type.

[0347] Method 2: If the prediction mode used for any coding block covered by the current node is inter prediction, then inter prediction is performed for all coding blocks covered by the current node; or, if the prediction mode used for any coding block covered by the current node is intra prediction, then intra prediction is performed for all coding blocks covered by the current node.

[0348] In this way, the prediction mode used for all coding blocks covered by the current node is actually determined based on the prediction mode used for any coding blocks covered by the current node.

[0349] Optionally, the given coding block is the first coding block of all coding blocks covered by the current node in decoding order. Specifically, the prediction mode of the first coding block B0 in the area of ​​the current node is analyzed, and in this embodiment, the prediction mode of the first coding block B0 is not limited. If the analysis finds that the prediction mode of the coding block B0 is intra prediction, intra prediction is performed on all coding blocks covered by the current node. If the analysis finds that the prediction mode of the coding block B0 is inter prediction, inter prediction is performed on all coding blocks covered by the current node.

[0350] It should be noted that the steps performed according to Method 1 and Method 2 above may be used in the video decoder 24 shown in FIG.

[0351] Step 2043: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0352] Optionally, after step 203 or step 2042 or step 2043, the method further comprises the following steps:

[0353] Step 205: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0354] Step 206: Decode each coding block to obtain a reconstructed signal of the image block corresponding to the current node.

[0355] Step 205 and step 206 in this embodiment are the same as step 105 and step 106 in the embodiment shown in Figure 9. For details, please refer to the previous embodiment, and the details will not be described again here.

[0356] According to the image prediction method provided in this embodiment, a partition mode of a current node is obtained; whether a luma block having a first preset size is obtained by dividing the current node in the luma block partition mode is determined based on the size of the current node and the luma block partition mode; if it is determined that a luma block having a first preset size is obtained by dividing the current node in the luma block partition mode, it is further determined whether a chroma block having a second preset size is obtained by dividing the current node in the chroma block partition mode; and if it is determined that a chroma block having the second preset size is obtained by dividing the current node in the chroma block partition mode, intra prediction or inter prediction is performed on all coding blocks covered by the current node. According to the above method, intra prediction or inter prediction is performed on all coding blocks of the current node, thereby enabling parallel processing of all coding blocks of the current node. This improves the processing performance of image prediction and increases the coding processing speed.

[0357] In the following, the image prediction method provided in the embodiment shown in FIG. 11 will be described with reference to two specific examples.

[0358] The first example is applicable to either YUV4:2:0 or YUV4:2:2 video data formats, or is applicable only to YUV4:2:0 video data format.

[0359] The image prediction method of this example includes the following steps.

[0360] Step 1: Get the split mode of the current node.

[0361] Step 2: Determine whether the area of the current node and the splitting mode of the current node satisfy at least one of the following conditions A: (1) The area of the current node is equal to 32, and the splitting mode of the current node is vertical binary tree splitting or horizontal binary tree splitting; or (2) The area of the current node is equal to 64, and the splitting mode of the current node is vertical ternary tree splitting, horizontal ternary tree splitting, or quadtree splitting.

[0362] When the area of the current node and the splitting mode of the current node satisfy at least one of the conditions A, Step 3 is executed.

[0363] Step 3: Restrict the execution of intra prediction for all coding blocks covered by the current node.

[0364] Optionally, the value of cons_pred_mode_flag is set to 1.

[0365] When the area of the current node and the splitting mode of the current node do not satisfy condition A, Step 4 is executed.

[0366] Step 4: Determine whether the area of the current node and the splitting mode of the current node satisfy at least one of the following conditions B: (1) The area S of the current node satisfies S / 2 < th1, and the splitting mode of the current node is vertical binary tree splitting or horizontal binary tree splitting; or (2) The area S of the current node satisfies S / 4 < th1, and the splitting mode of the current node is vertical ternary tree splitting, horizontal ternary tree splitting, or quadtree splitting.

[0367] The threshold th1 is related to the video data format. For example, when the video data format is YUV4:2:0, the threshold th1 is 64; or when the video data format is YUV4:2:2, the threshold th1 is 32.

[0368] If the area of ​​the current node and the division mode of the current node satisfy at least one of the conditions B, step 5 is executed.

[0369] Step 5: Analyze the flag cons_pred_mode_flag from the bitstream, and determine to perform inter prediction or intra prediction for all coding units within the coverage area of ​​the current node based on the value of cons_pred_mode_flag.

[0370] If the area of ​​the current node and the partitioning mode of the current node do not satisfy condition B, step 6 is performed.

[0371] Step 6: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0372] Optionally, after step 6, the method further comprises the following steps:

[0373] Step 7: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0374] Step 8: Decode each coding block to obtain the reconstructed signal of the image block corresponding to the current node.

[0375] The second example is applicable to the YUV4:2:0 video data format.

[0376] The image prediction method of this example includes the following steps.

[0377] Step 1: Get the split mode of the current node.

[0378] Step 2: Determine whether the area of ​​the current node and the partitioning mode of the current node satisfy condition C. The area of ​​the current node is equal to 64, and the partitioning mode of the current node is horizontal ternary tree partitioning, vertical ternary tree partitioning, or quadtree partitioning.

[0379] If the area of ​​the current node and the partitioning mode of the current node satisfy condition C, step 3 is executed.

[0380] Step 3: Intra prediction is performed for all coding units within the coverage area of ​​the current node.

[0381] Optionally, the value of cons_pred_mode_flag is set to 1.

[0382] If the area of ​​the current node and the partitioning mode of the current node do not satisfy condition C, step 4 is performed.

[0383] Step 4: Determine whether the area of ​​the current node and the division mode of the current node satisfy at least one of the following conditions D: (1) The area of ​​the current node is equal to 64, and the partitioning mode of the current node is horizontal binary tree partitioning or vertical binary tree partitioning; or (2) The area of ​​the current node is equal to 128, and the splitting mode of the current node is horizontal ternary tree splitting or vertical ternary tree splitting.

[0384] If the area of ​​the current node and the partitioning mode of the current node satisfy at least one of the conditions D, step 5 is executed.

[0385] Step 5: Analyze the flag cons_pred_mode_flag from the bitstream, and determine to perform inter prediction or intra prediction for all coding units within the coverage area of ​​the current node based on the value of cons_pred_mode_flag.

[0386] If the area of ​​the current node and the partitioning mode of the current node do not satisfy condition D, step 6 is performed.

[0387] Step 6: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0388] Optionally, after step 6, the method further comprises the following steps:

[0389] Step 7: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0390] Step 8: Decode each coding block to obtain the reconstructed signal of the image block corresponding to the current node.

[0391] 12 is a schematic flowchart of a fourth image prediction method according to an embodiment of the present application. As shown in FIG. 12, the image prediction method provided in this embodiment includes the following steps:

[0392] Step 301: Obtain the split mode of the current node.

[0393] Specifically, the division information of the current node is analyzed. If the division information indicates that the chroma block of the current node is to be divided, a division mode of the chroma block of the current node is further determined. The division mode of the chroma block includes at least one of quadtree division, vertical binary tree division, horizontal binary tree division, vertical ternary tree division, and horizontal ternary tree division. Of course, there may be other division modes, which are not particularly limited in this embodiment.

[0394] Step 302: Based on the size of the current node and the split mode of the current node, determine whether a chroma block having a second preset size is obtained by splitting the current node in the split mode.

[0395] If it is determined that a chroma block having a second preset size is obtained by dividing the current node in the division mode, step 303 is executed. If it is determined that a chroma block having a second preset size is not obtained by dividing the current node in the division mode, step 304 is executed.

[0396] Step 302 in this embodiment is the same as step 2041 in the embodiment shown in Figure 11. For details, please refer to the previous embodiment, and the details will not be described again here.

[0397] Optionally, step 302 may include determining, based on the size of the current node and the splitting mode of the current node, whether a luma block having a third preset size is obtained by splitting the current node in the splitting mode.

[0398] Optionally, the luma block having the third preset size may be a 4x4, 4x8, or 8x4 luma block.

[0399] Optionally, determining whether a chroma block having a second preset size is obtained by splitting the current node in the split mode may be performed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is quadtree partitioning; (2) The number of samples in the luma block of the current node is 64, and the partitioning mode is ternary tree partitioning; (3) The number of samples in the luma block of the current node is 32, and the partitioning mode is binary tree partitioning; (4) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (5) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0400] Optionally, the chroma blocks having the second preset size may be chroma blocks having a pixel size of 2x4 or 4x2 (except for chroma blocks having a pixel size of 2x2). Similarly, the luma blocks having the third preset size may be luma blocks having a pixel size of 4x8 or 8x4 (except for luma blocks having a pixel size of 4x4). Correspondingly, the step of determining whether a chroma block having the second preset size is obtained by splitting the current node in the split mode may be performed based on one of the following conditions: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode is binary tree partitioning; or (2) The number of samples in the luma block of the current node is 128, and the partitioning mode is ternary tree partitioning.

[0401] Step 303: Perform intra prediction or inter prediction on all coding blocks covered by the current node.

[0402] Whether to perform intra prediction or inter prediction for all coding blocks covered by the current node may be determined based on step 2042 of the embodiment shown in Figure 11. For details, please refer to the above-mentioned embodiment, and the details will not be described again here.

[0403] Step 304: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0404] Step 304 in this embodiment is the same as step 104 in the embodiment shown in Figure 9. For details, please refer to the previous embodiment, and the details will not be described again here.

[0405] Optionally, after step 303 or step 304, the method further comprises the following steps:

[0406] Step 305: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0407] Step 306: Decode each coding block to obtain a reconstructed signal of the image block corresponding to the current node.

[0408] Step 305 and step 306 in this embodiment are the same as step 105 and step 106 in the embodiment shown in Figure 9. For details, please refer to the previous embodiment, and the details will not be described again here.

[0409] According to the image prediction method provided in this embodiment, a partition mode of a current node is obtained, and whether dividing the current node in the partition mode will result in a chroma block having a second preset size is determined based on the size of the current node and the partition mode of the current node; and if it is determined that dividing the current node in the partition mode will result in a chroma block having the second preset size, intra prediction or inter prediction is performed on all coding blocks covered by the current node. According to the above method, intra prediction or inter prediction is performed on all coding blocks of the current node, so that parallel processing can be performed on all coding blocks of the current node. This improves the processing performance of image prediction and increases the coding processing speed.

[0410] 13 is a schematic flowchart of a fifth image prediction method according to an embodiment of the present application. Based on the embodiment shown in FIG. 12, if it is determined that a chroma block having a second preset size is obtained by splitting the current node in a split mode, as shown in FIG. 13, step 304 may include the following steps:

[0411] Step 3041: Determine whether a luma block having a first preset size is obtained by dividing the current node in a division mode.

[0412] If it is determined that a luma block having a first preset size is obtained by dividing the current node in the split mode, then step 3042 is executed. If it is determined that a luma block having a first preset size is not obtained by dividing the current node in the split mode, then step 3043 is executed.

[0413] Specifically, based on the size of the current node and the luma block division mode, it is determined whether a luma block having a first preset size is obtained by dividing the current node according to the luma block division mode. The luma block having the first preset size is a luma block having a pixel size of 4x4. The specific determination process is the same as the process in step 202 of the embodiment shown in Figure 10, and reference can be made to the aforementioned embodiment. The details will not be described again here.

[0414] Step 3042: Perform intra prediction for all coding blocks covered by the current node.

[0415] Step 3043: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0416] Optionally, after step 303 or step 3042 or step 3043, the method further comprises the following steps:

[0417] Step 305: Analyze the prediction blocks and residual information of all coding blocks covered by the current node.

[0418] Step 306: Decode each coding block to obtain a reconstructed signal of the image block corresponding to the current node.

[0419] Step 305 and step 306 in this embodiment are the same as step 105 and step 106 in the embodiment shown in Figure 9. For details, please refer to the previous embodiment, and the details will not be described again here.

[0420] According to the image prediction method provided in this embodiment, a partition mode of a current node is obtained; whether a chroma block having a second preset size is obtained by dividing the current node in the partition mode is determined based on the size of the current node and the partition mode of the current node; if it is determined that a chroma block having the second preset size is not obtained by dividing the current node in the partition mode, it is further determined whether a luma block having a first preset size is obtained by dividing the current node in the partition mode; and if it is determined that a luma block having the first preset size is obtained by dividing the current node in the partition mode, intra prediction is performed on all coding blocks covered by the current node. According to the above method, intra prediction or inter prediction is performed on all coding blocks of the current node, allowing parallel processing to be performed on all coding blocks of the current node. This improves the processing performance of image prediction and increases the coding processing speed.

[0421] 14 is a schematic flowchart of a sixth image prediction method according to an embodiment of the present application. The image prediction method provided in this embodiment is used in the video encoder 18 shown in FIG. 8. As shown in FIG. 14, the method of this embodiment includes the following steps:

[0422] Step 401: Obtain the partition mode of the current node.

[0423] The type of the slice in which the current node is located is type B or type P. It should be understood that if the type of the slice in which the current node is located is type I, intra prediction needs to be performed on all coding blocks covered by the current node by default.

[0424] The decoder side can obtain the partition mode of the current node by analyzing the bitstream or based on the obtained parameters. The encoder side generally first determines the partition modes allowed for the current node, and then determines the optimal partition mode as the partition mode of the current node according to a rate-distortion optimization (RDO) method. This step belongs to the prior art, and the details are not described here.

[0425] Step 402: Determine whether the size of the current node and the split mode of the current node satisfy one of the first preset conditions.

[0426] The first preset condition may include: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode of the current node is quadtree partitioning; (2) The number of samples in the luma block of the current node is 64, and the partitioning mode of the current node is ternary tree partitioning; or (3) The number of samples in the luma block of the current node is 32, and the partitioning mode of the current node is binary tree partitioning.

[0427] The number of samples of the luma block of the current node is the number of luma pixels (pixel size) of the image block corresponding to the current node. The number of samples may be obtained based on the product of the width and height of the current node.

[0428] In another embodiment, the first preset condition further comprises the following condition (4): (4) A luma block with a preset size is obtained by dividing the current node in a division mode, where the preset size is 4x4 or 8x8.

[0429] It should be noted that a luma block having a first preset size (4x4 or 8x8) and a chroma block having a second preset size (2x4 or 4x2) can be obtained if one of the first preset conditions is met.

[0430] In this step, if the size of the current node and the split mode of the current node satisfy one of the first preset conditions, step 403 is executed. If the size of the current node and the split mode of the current node do not satisfy any of the first preset conditions, step 404 is executed.

[0431] Step 403: Perform intra prediction for all coding blocks covered by the current node.

[0432] Optionally, if it is determined to perform intra prediction for all coding blocks covered by the current node, there is no need to write the value of mode_constraint_flag into the bitstream, and the value of mode_constraint_flag may be set to 1. Correspondingly, the decoder side may also derive the value of mode_constraint_flag to be 1 according to the same method.

[0433] Step 404: Determine whether the size of the current node and the split mode of the current node satisfy one of the second preset conditions.

[0434] The second preset condition includes: (1) The number of samples in the luma block of the current node is 64, and the partitioning mode of the current node is vertical binary tree partitioning or horizontal binary tree partitioning; or (2) The number of samples in the luma block of the current node is 128, and the division mode of the current node is vertical ternary tree division or horizontal ternary tree division.

[0435] In another embodiment, the second preset condition further comprises the following condition (3): (3) A chroma block with a preset size is obtained by dividing the current node in a division mode, where the preset size is 2x4 or 4x2.

[0436] In this step, if the size of the current node and the split mode of the current node satisfy one of the second preset conditions, step 405 is executed. If the size of the current node and the split mode of the current node do not satisfy any of the second preset conditions, step 406 is executed.

[0437] Step 405: Perform intra prediction or inter prediction on all coding blocks covered by the current node.

[0438] In this embodiment, the prediction mode used for all coding blocks of the current node can be determined in several ways:

[0439] In one embodiment, if the type of the image or slice where the current node is located is I-type, the encoder or encoder side determines that only intra prediction (non-inter prediction) is applicable to all coding blocks of the current node. Optionally, the encoder or encoder side does not need to write mode_constraint_flag into the bitstream and may set the value of mode_constraint_flag to 1.

[0440] If the type of the image or slice where the current node is located is not I-type, the encoder or the encoder side determines the value of mode_constraint_flag according to a rate-distortion optimization (RDO) method or another method.

[0441] The RDO method is specifically as follows: The encoder separately calculates the rate-distortion cost (RD cost) generated when performing inter prediction and intra prediction for all coding blocks covered by the current node, compares the rate-distortion cost values ​​generated for the two prediction modes, and determines the prediction mode with the smaller rate-distortion cost as the final prediction mode. If the prediction mode with the smaller rate-distortion cost is intra prediction, the encoder sets the value of mode_constraint_flag to 1. If the prediction mode with the smaller rate-distortion cost is inter prediction, the encoder sets the value of mode_constraint_flag to 0 and writes the value of mode_constraint_flag into the bitstream.

[0442] For example, the encoder first calculates the RD cost generated when performing inter prediction on all coding blocks covered by the current node, and then calculates the RD cost generated when performing intra prediction. If there is no residue when performing inter prediction on all coding blocks covered by the current node (e.g., skip mode is used), the encoder determines that inter prediction is performed on all coding blocks covered by the current node, sets the value of mode_constraint_flag to 0, and does not need to calculate the RD cost generated in the case of intra prediction. Alternatively, the encoder can first calculate the RD cost generated when performing intra prediction on all coding blocks covered by the current node, and then calculate the RD cost generated when performing inter prediction, and determine the prediction mode with the smaller RD cost as the final prediction mode.

[0443] Note that if the current node is located in an intra-image region (i.e., the type or slice (slice_type) of the image where the current node is located is intra-type or I-type) and the use of IBC mode is allowed, the value of pred_mode_flag defaults to 1. If the current node is located in an intra-image region but the use of IBC mode is not allowed, the value of pred_mode_flag defaults to 1 and the value of cu_skip_flag defaults to 0 (indicating that skip mode is not used for the current block). If the current node is located in an intra-image region (i.e., the type or slice (slice_type) of the image where the current node is located is intra-type or I-type), the value of mode_constraint_flag defaults to 1.

[0444] In one embodiment, the decoder side or decoder can analyze the prediction mode status flag (mode_constraint_flag) of the current node; if the value of the prediction mode status flag is a first value, perform inter prediction for all coding blocks belonging to the current node; or if the value of the prediction mode status flag is a second value, perform intra prediction for all coding blocks belonging to the current node.

[0445] Step 406: Split the current node with the split mode of the current node, where the prediction modes used for all coding blocks covered by the current node are not restricted.

[0446] Optionally, after step 403, step 405 or step 406, the method may further include the following steps:

[0447] Step 407: Based on the prediction mode of the current node, determine whether the luma block and chroma block of the current node are further divided.

[0448] When it is determined that only intra prediction is performed on all coding blocks of the current node, the luma block included in the current node is divided in a division mode to obtain a luma block obtained by the division, and intra prediction is performed on the luma block obtained by the division; and the chroma block included in the current node is used as a chroma coding block, and intra prediction is performed on the chroma coding block. In other words, when it is determined that intra prediction is performed on all coding blocks of the current node, the luma block of the current node is divided in a luma block division mode to obtain N luma coding tree nodes; and the chroma block of the current node is not divided, and one chroma coding block (chroma CB for short) is obtained. The N luma coding tree nodes may or may not be limited to not being further divided. When the luma coding tree node is further divided, the division mode of the luma coding tree node is analyzed for recursive division. When the luma coding tree node is not further divided, the luma coding tree node corresponds to one luma coding block (luma CB for short). Intra prediction is performed on the luma CB to obtain a luma prediction block corresponding to the luma CB. Intra prediction is performed on the chroma CB to obtain a chroma prediction block corresponding to the chroma CB. The chroma prediction block and the chroma CB have the same size.

[0449] When it is determined to perform only intra prediction for all coding blocks of the current node, in another embodiment, the luma blocks and chroma blocks included in the current node are split in a split mode to obtain nodes obtained by the split. When the coding tree node is not split any further, the coding tree node corresponds to one coding unit and includes a luma coding unit and a chroma coding unit. Intra prediction is performed on the luma coding unit and the chroma coding unit, where the luma coding unit and the chroma coding unit are obtained by the split.

[0450] When it is determined to perform only inter prediction for all coding blocks of the current node, in one embodiment, the luma block included in the current node is divided in a partition mode to obtain luma blocks obtained by the division, and inter prediction is performed on the luma blocks obtained by the division; and the chroma blocks included in the current node are divided in a partition mode to obtain chroma blocks obtained by the division, and inter prediction is performed on the chroma blocks obtained by the division. In other words, when it is determined to perform inter prediction for all coding blocks of the current node, the luma block of the current node is divided in a luma block partition mode to obtain N luma coding tree nodes; and the chroma block of the current node is divided in a chroma block partition mode to obtain M chroma coding tree nodes. N and M are positive integers, and N and M may be the same or different. The N luma coding tree nodes and the M chroma coding tree nodes may be restricted to not be further divided, or this is not restricted. When no further division is performed, the N luma coding tree nodes correspond to the N luma CBs of the current node, and the M chroma coding tree nodes correspond to the M chroma CBs of the current node. Inter prediction is performed on the N luma CBs to obtain corresponding luma prediction blocks, and inter prediction is performed on the M chroma CBs to obtain corresponding chroma prediction blocks.

[0451] When it is determined to perform only inter prediction for all coding blocks of the current node, in one embodiment, the luma block included in the current node is divided in a partition mode to obtain luma blocks obtained by the division, and inter prediction is performed on the luma blocks obtained by the division; and the chroma blocks included in the current node are divided in a partition mode to obtain chroma blocks obtained by the division, and inter prediction is performed on the chroma blocks obtained by the division. In other words, when it is determined to perform inter prediction for all coding blocks of the current node, the luma block of the current node is divided in a luma block partition mode to obtain N luma coding tree nodes; and the chroma block of the current node is divided in a chroma block partition mode to obtain M chroma coding tree nodes. N and M are positive integers, and N and M may be the same or different. The N luma coding tree nodes and the M chroma coding tree nodes may be restricted to not be further divided, or this is not restricted. When no further division is performed, the N luma coding tree nodes correspond to the N luma CBs of the current node, and the M chroma coding tree nodes correspond to the M chroma CBs of the current node. Inter prediction is performed on the N luma CBs to obtain corresponding luma prediction blocks, and inter prediction is performed on the M chroma CBs to obtain corresponding chroma prediction blocks.

[0452] In particular, when only inter prediction is performed on all coding blocks of a current node, a child node is obtained by dividing the current node in a division mode, and the child node needs to be further divided, and a luma block having a preset size is obtained by dividing the child node in a division mode, where, for example, the preset size is 4x4 (i.e., both the width and the height are 4), and the division mode of the child node is not allowed, or further division of the child node is not allowed. Specifically, when a node is restricted to only perform inter prediction and the number of luma samples of the node is 32 (i.e., the product of the width and height of the node is 32), binary tree division (including horizontal binary tree division or vertical binary tree division) is not allowed for the node. When a node is restricted to only perform inter prediction and the number of luma samples of the node is 64 (i.e., the product of the width and height of the node is 64), ternary tree division (including horizontal ternary tree division or vertical ternary tree division) is not allowed for the node. Such a determination method is applicable to both YUV4:2:0 and YUV4:2:2 video data formats.

[0453] For example, if the size of the current node is 8x8 and two 8x4 (or 4x8) nodes are generated by horizontal binary tree splitting (or vertical binary tree splitting), further dividing the 8x4 (or 4x8) node generates a 4x4 block. In this case, vertical binary tree splitting (or horizontal binary tree splitting) is not allowed for the 8x4 (or 4x8) node, or further division of the 8x4 (or 4x8) node is not allowed. As another example, if the number of samples in the luma block of the current node is 128 and the partitioning mode is horizontal ternary tree splitting or vertical ternary tree splitting, the number of samples in the luma block may be determined to be 64. However, if horizontal ternary tree splitting or vertical ternary tree splitting of the child node is used for a luma node with a sample quantity of 64, a 4x4 luma block is obtained. Therefore, when only inter-prediction is restricted to be performed, horizontal or vertical ternary tree divisions are not allowed for nodes with a quantity of 64 samples, or further division of nodes with a quantity of 64 samples is not allowed.

[0454] Step 408: Predict the coding block of the CU obtained by splitting the current node to obtain a predictor of the coding block.

[0455] If only intra prediction is performed for all coding blocks of the current node, the encoder or encoder side determines the optimal intra prediction mode to be used for the current coding block according to a rate-distortion optimization (RDO) method or another method; and then predicts the current coding block using the corresponding intra prediction mode to obtain a predictor for the current block.

[0456] If only inter prediction is performed for all coding blocks of the current node, the encoder or encoder side determines the optimal inter prediction mode to be used for the current coding block according to a rate-distortion optimization method or another method; and then predicts the current coding block using the corresponding inter prediction mode to obtain a predictor for the current block.

[0457] Furthermore, the encoder assigns values ​​to CU depth-related syntax elements and writes the values ​​of each syntax element to the bitstream according to the criteria of the CU-level syntax specification. For example, if only intra prediction is performed for all coding blocks of the current node, the value of pred_mode_flag is set to 1, and pred_mode_flag is not written to the bitstream. That is, pred_mode_flag does not exist in the bitstream. If it is determined that only intra prediction is performed for all coding blocks of the current node and the IBC mode is not used, the value of cu_skip_flag (or skip_flag) is 0, and cu_skip_flag is not written to the bitstream. In other words, if it is determined that only intra prediction is performed for all coding blocks of the current node and the IBC mode is not used, the value of cu_skip_flag (or skip_flag) is 0, and cu_skip_flag is not written to the bitstream. In other cases, after determining the value of cu_skip_flag, cu_skip_flag needs to be written to the bitstream, and the cu_skip_flag is transmitted to the decoder side.

[0458] When only inter prediction is performed for all coding blocks of the current node, the value of pred_mode_flag is set to 0, and pred_mode_flag is not written to the bitstream. That is, pred_mode_flag is not present in the bitstream. When the value of pred_mode_ibc_flag is set to 0, pred_mode_ibc_flag is not written to the bitstream. That is, pred_mode_ibc_flag is not present in the bitstream.

[0459] If only intra prediction is performed for all coding blocks of the current node, the decoder or decoder side can determine the optimal intra prediction mode to be used for the current coding block by analyzing the bitstream or based on the obtained parameters; and then predict the current coding block using the corresponding intra prediction mode to obtain a predictor for the current block.

[0460] If only inter prediction is performed for all coding blocks of the current node, the decoder or decoder side can determine the optimal inter prediction mode to be used for the current coding block by analyzing the bitstream or based on the obtained parameters; and then predict the current coding block using the corresponding inter prediction mode to obtain a predictor for the current block.

[0461] Step 409: Obtain the reconstructed signal of the image block at the current node.

[0462] After obtaining prediction information through intra prediction or inter prediction, the encoder or encoder side obtains residual information by subtracting corresponding prediction information (or predictor) from pixel values ​​of pixels in the current coding block, transforms the residual information using a method such as Discrete Cosine Transform (DCT), obtains a bitstream through quantization and entropy coding, and transmits the residual information to the decoder side. After adding the prediction signal and the reconstructed residual signal, the encoder side must further perform a filtering operation to obtain a reconstructed signal, which is used as a reference signal for subsequent encoding. In particular, when skip mode is used for a coding block, there is no residual information, so there is no need to perform transformation on the encoder side, and the predictor becomes the final reconstructed value.

[0463] After adding the prediction signal and the reconstructed residual signal, the decoder or decoder side needs to further perform a filtering operation to obtain a reconstructed signal. Furthermore, the decoder side uses the obtained reconstructed signal as a reference signal for subsequent encoding. In particular, when skip mode is used for a coding block, there is no residual information, so the decoder or decoder side does not need to perform a transform, and the predictor becomes the final reconstructed value.

[0464] For example, based on the prediction block of the CU, an inter prediction process or an intra prediction process is performed on each CU to obtain an inter prediction image or an intra prediction image of the CU. Then, based on the residual information of each CU, a dequantization and inverse transform process is performed on the transform coefficients to obtain a residual image, and the residual image is added to the prediction image of the corresponding region to generate a reconstructed image.

[0465] In this embodiment, the image prediction method is described from the perspective of a video decoder. The video decoder determines whether to perform intra prediction or inter prediction on all coding blocks of the current node based on the size of the current node and the partition mode of the current node, so that parallel processing can be performed on all coding blocks of the current node. This improves the processing performance of image prediction and increases the decoding processing speed.

[0466] The image prediction method provided in one embodiment is used for the video encoder 18 and / or the video decoder 24 shown in Figure 8. This embodiment includes the following steps.

[0467] Step 501: Obtain the split mode of the current node.

[0468] Step 501 in this embodiment is the same as step 101 in the embodiment shown in FIG. 9, and the details will not be described again here.

[0469] Step 502: Derive the value of the variable modeTypeCondition according to the following method.

[0470] The value of modeTypeCondition is a first value, e.g., 0, if one or more of the following first preset conditions are true: (1) The type of the image or slice where the current node is located is I type (slice_type == I), and the value of qtbtt_dual_tree_intra_flag is 1; (2) The prediction mode type of the current node is only intra-prediction or inter-prediction, i.e., is restricted to only performing inter-prediction or intra-prediction (non-inter-prediction); or (3) The chroma format is a monochrome format or a 4:4:4 format, and for example, the value of chroma_format_idc is 0 or 3.

[0471] In another embodiment, the first preset condition further includes the following condition (4): (4) The chroma format is monochrome format, 4:4:4 format, or 4:2:2 format, for example, the value of chroma_format_idc is 0, 3, or 2.

[0472] Otherwise, if one or more of the following second preset conditions are true, the value of modeTypeCondition is a second value, e.g., 1: (1) The product of the width and height of the luma block of the current node is 64, and the partitioning mode of the current node is quadtree partitioning; (2) The product of the width and height of the luma block of the current node is 64, and the partitioning mode of the current node is horizontal ternary tree partitioning or vertical ternary tree partitioning; or (3) The product of the width and height of the luma block of the current node is 32, and the partitioning mode of the current node is horizontal binary tree partitioning or vertical binary tree partitioning.

[0473] Otherwise, if one or more of the following preset third conditions are true and the chroma format is 4:2:0 (the value of chroma_format_idc is 1), the value of modeTypeCondition is derived according to the following formula: 1 + (slice_type != I? 1: 0): (1) The product of the width and height of the luma block of the current node is 64, and the partitioning mode of the current node is horizontal binary tree partitioning or vertical binary tree partitioning; or (2) The product of the width and height of the luma block of the current node is 128, and the partitioning mode of the current node is horizontal ternary tree partitioning or vertical ternary tree partitioning.

[0474] Note that Table 3 shows the correspondence between chroma formats and chroma_format_idc. [Table 3]

[0475] In monochrome sampling, there is no chroma component format, only a series of luma components.

[0476] In 4:2:0 sampling, the width of the two chroma components is half the width of the corresponding luma component, and the height of the chroma components is half the height of the luma components.

[0477] In 4:2:2 sampling, the height of the two chroma components is the same as the height of the corresponding luma component, and the width of the chroma components is half the width of the corresponding luma component.

[0478] In 4:4:4 sampling, the height and width of the two chroma components depend on the value of separate_colour_plane_flag: if the value of separate_colour_plane_flag is equal to 0, the width and height of the two chroma components are the same as the width and height of the corresponding luma component, respectively. Otherwise (the value of separate_colour_plane_flag is equal to 1), the three components are coded separately as monochrome sample images.

[0479] separate_colour_plane_flag equal to 1 specifies that the three color components of the 4:4:4 chroma format are coded separately. separate_colour_plane_flag equal to 0 specifies that the color components are not coded separately.

[0480] qtbtt_dual_tree_intra_flag equal to 1 specifies that for an I-slice, each CTU is divided into coding units with 64x64 luma samples using implicit quadtree partitioning, and these coding units are the roots of two separate coding_tree syntax structures, one for luma and one for chroma. qtbtt_dual_tree_intra_flag equal to 0 specifies that separate coding_tree syntax structures are not used for I-slices. If qtbtt_dual_tree_intra_flag is not present, it is inferred to be equal to 0.

[0481] Step 503: Determine the prediction mode types of all coding units of the current node according to the value of modeTypeCondition.

[0482] Specifically, when the value of modeTypeCondition is 1, intra prediction (MODE_INTRA) is restricted to be performed for all coding units of the current node. When the value of modeTypeCondition is 2, the value of the syntax element mode_constraint_flag is parsed from the bitstream. When the value of mode_constraint_flag is 0, inter prediction (MODE_INTER) is performed for all coding units of the current node. When the value mode_constraint_flag is 1, intra prediction (non-inter prediction / MODE_INTRA) is performed for all coding units of the current node.

[0483] Otherwise, the prediction mode type of all coding units of the current node is not restricted and is the same as the prediction mode type of the current node.

[0484] Step 504: Determine whether the chroma block and luma block corresponding to the current node are further divided to obtain chroma coding units and luma coding units.

[0485] (Step 504 is the same as step 407).

[0486] When it is determined that only intra prediction is performed on all coding blocks of the current node, the luma block included in the current node is divided in a division mode to obtain a luma block obtained by the division, and intra prediction is performed on the luma block obtained by the division; and the chroma block included in the current node is used as a chroma coding block, and intra prediction is performed on the chroma coding block. In other words, when it is determined that intra prediction is performed on all coding blocks of the current node, the luma block of the current node is divided in a luma block division mode to obtain N luma coding tree nodes; and the chroma block of the current node is not divided, and one chroma coding block (chroma CB for short) is obtained. The N luma coding tree nodes may or may not be limited to not being further divided. When the luma coding tree node is further divided, the division mode of the luma coding tree node is analyzed for recursive division. When the luma coding tree node is not further divided, the luma coding tree node corresponds to one luma coding block (luma CB for short). Intra prediction is performed on the luma CB to obtain a luma prediction block corresponding to the luma CB. Intra prediction is performed on the chroma CB to obtain a chroma prediction block corresponding to the chroma CB. The chroma prediction block and the chroma CB have the same size.

[0487] When it is determined that only intra prediction is performed for all coding blocks of the current node, in another embodiment, the luma blocks and chroma blocks included in the current node are split in a split mode to obtain nodes obtained by the split. When the coding tree node is not split any further, the coding tree node corresponds to one coding unit and includes a luma coding unit and a chroma coding unit. Intra prediction is performed on the luma coding unit and the chroma coding unit, and the luma coding unit and the chroma coding unit are obtained by the split.

[0488] When it is determined to perform only inter prediction for all coding blocks of the current node, in one embodiment, the luma block included in the current node is divided in a partition mode to obtain luma blocks obtained by the division, and inter prediction is performed on the luma blocks obtained by the division; and the chroma blocks included in the current node are divided in a partition mode to obtain chroma blocks obtained by the division, and inter prediction is performed on the chroma blocks obtained by the division. In other words, when it is determined to perform inter prediction for all coding blocks of the current node, the luma block of the current node is divided in a luma block partition mode to obtain N luma coding tree nodes; and the chroma block of the current node is divided in a chroma block partition mode to obtain M chroma coding tree nodes. N and M are positive integers, and N and M may be the same or different. The N luma coding tree nodes and the M chroma coding tree nodes may be restricted to not be further divided, or this is not restricted. When no further division is performed, the N luma coding tree nodes correspond to the N luma CBs of the current node, and the M chroma coding tree nodes correspond to the M chroma CBs of the current node. Inter prediction is performed on the N luma CBs to obtain corresponding luma prediction blocks, and inter prediction is performed on the M chroma CBs to obtain corresponding chroma prediction blocks.

[0489] When it is determined to perform only inter prediction for all coding blocks of the current node, in one embodiment, the luma block included in the current node is divided in a partition mode to obtain luma blocks obtained by the division, and inter prediction is performed on the luma blocks obtained by the division; and the chroma blocks included in the current node are divided in a partition mode to obtain chroma blocks obtained by the division, and inter prediction is performed on the chroma blocks obtained by the division. In other words, when it is determined to perform inter prediction for all coding blocks of the current node, the luma block of the current node is divided in a luma block partition mode to obtain N luma coding tree nodes; and the chroma block of the current node is divided in a chroma block partition mode to obtain M chroma coding tree nodes. N and M are positive integers, and N and M may be the same or different. The N luma coding tree nodes and the M chroma coding tree nodes may be restricted to not be further divided, or this is not restricted. When no further division is performed, the N luma coding tree nodes correspond to the N luma CBs of the current node, and the M chroma coding tree nodes correspond to the M chroma CBs of the current node. Inter prediction is performed on the N luma CBs to obtain corresponding luma prediction blocks, and inter prediction is performed on the M chroma CBs to obtain corresponding chroma prediction blocks.

[0490] In particular, when only inter prediction is performed for all coding blocks of a current node, a child node is obtained by dividing the current node in a division mode, and the child node needs to be further divided, and a luma block having a preset size is obtained by dividing the current node in a division mode, for example, the preset size is 4x4 (i.e., both the width and height are 4), and the division mode of the child node is not permitted, or further division of the child node is not permitted. Specifically, when a node is restricted to only perform inter prediction and the number of luma samples of the node is 32 (i.e., the product of the width and height of the node is 32), binary tree division (including horizontal binary tree division or vertical binary tree division) is not permitted for the node. When a node is restricted to only perform inter prediction and the number of luma samples of the node is 64 (i.e., the product of the width and height of the node is 64), ternary tree division (including horizontal ternary tree division or vertical ternary tree division) is not permitted for the node. Such a determination method is applicable to both YUV4:2:0 and YUV4:2:2 video data formats.

[0491] For example, if the size of the current node is 8x8 and two 8x4 (or 4x8) nodes are generated by horizontal binary tree splitting (or vertical binary tree splitting), further dividing the 8x4 (or 4x8) node generates a 4x4 block. In this case, vertical binary tree splitting (or horizontal binary tree splitting) is not allowed for the 8x4 (or 4x8) node, or further division of the 8x4 (or 4x8) node is not allowed. As another example, if the number of samples in the luma block of the current node is 128 and the partitioning mode is horizontal ternary tree splitting or vertical ternary tree splitting, the number of samples in the luma block may be determined to be 64. However, if horizontal ternary tree splitting or vertical ternary tree splitting of the child node is used for a luma node with a sample quantity of 64, a 4x4 luma block is obtained. Therefore, when restricted to performing only inter prediction, horizontal or vertical ternary tree divisions are not allowed for nodes with a quantity of 64 samples, or for further division of nodes with a quantity of 64 samples.

[0492] Step 505: Parse the coding unit to obtain prediction mode information.

[0493] Based on the prediction mode type of the coding unit, the final prediction mode of the coding unit is obtained by analyzing syntax elements related to intra-prediction or inter-prediction, and prediction is performed in the corresponding prediction mode to obtain a predictor.

[0494] If the current node is located in an intra-picture region (i.e., the type or slice (slice_type) of the picture where the current node is located is intra-type or I-type) and the use of IBC mode is allowed, the value of cu_pred_mode is derived as 1, and the value of cu_pred_mode is obtained without the need to parse the bitstream. If the current node is located in an intra-picture region but the use of IBC mode is not allowed, the value of cu_pred_mode is derived as 1, the value of cu_skip_flag is 0, and the value of cu_pred_mode is obtained without the need to parse the bitstream.

[0495] If the current node is located in an inter-image region (i.e., the type or slice (slice_type) of the image where the current node is located is inter-type or B-type), the value of cu_pred_mode is derived as 0, and the value of cu_pred_mode is obtained without the need to parse the bitstream.

[0496] Step 506: Decode each coding block to obtain a reconstructed signal of the image block corresponding to the current node.

[0497] For example, based on the prediction block of the CU, an inter prediction process or an intra prediction process is performed on each CU to obtain an inter prediction image or an intra prediction image of the CU. Then, based on the residual information of each CU, a dequantization and inverse transform process is performed on the transform coefficient to obtain a residual image, and the residual image is added to the prediction image of the corresponding region to generate a reconstructed image.

[0498] Encoder side solutions:

[0499] The image prediction method provided in one embodiment is used in the video encoder 18 shown in Figure 8. This embodiment includes the following steps.

[0500] Step 601: Obtain the split mode of the current node.

[0501] Step 601 in this embodiment is the same as step 501, and the details will not be described again here.

[0502] Step 602: Derive the value of the variable modeTypeCondition according to the following method.

[0503] The value of modeTypeCondition is a first value, e.g., 0, if one or more of the following first preset conditions are true: (1) The type of the image or slice where the current node is located is I type (slice_type == I), and the value of qtbtt_dual_tree_intra_flag is 1; (2) The prediction mode type of the current node is only intra prediction or inter prediction, i.e., it is restricted to only perform inter prediction or intra prediction (non-inter prediction); or (3) Chroma format is monochrome format or 4:4:4 format, where, for example, the value of chroma_format_idc is 0 or 3.

[0504] In another embodiment, the first preset condition further comprises the following condition (4): (4) The chroma format is a monochrome format, a 4:4:4 format, or a 4:2:2 format, where, for example, the value of chroma_format_idc is 0, 3, or 2.

[0505] Otherwise, the value of modeTypeCondition is a second value, e.g., 1, if one or more of the following second preset conditions are true: (1) The product of the width and height of the luma block of the current node is 64, and the partitioning mode of the current node is quadtree partitioning; (2) The product of the width and height of the luma block of the current node is 64, and the partitioning mode of the current node is horizontal ternary tree partitioning or vertical ternary tree partitioning; or (3) The product of the width and height of the luma block of the current node is 32, and the partitioning mode of the current node is horizontal binary tree partitioning or vertical binary tree partitioning.

[0506] Otherwise, if one or more of the following preset third conditions are true and the chroma format is 4:2:0 (the value of chroma_format_idc is 1), the value of modeTypeCondition is derived according to the following formula: 1 + (slice_type != I? 1: 0): (1) The product of the width and height of the luma block of the current node is 64, and the partitioning mode of the current node is horizontal binary tree partitioning or vertical binary tree partitioning; or (2) The product of the width and height of the luma block of the current node is 128, and the partitioning mode of the current node is horizontal ternary tree partitioning or vertical ternary tree partitioning.

[0507] Step 603: Determine the prediction mode types of all coding units of the current node according to the value of modeTypeCondition.

[0508] Specifically, all coding units of the current node are restricted from performing intra prediction (MODE_INTRA) when the value of modeTypeCondition is 1. Optionally, the value of mode_constraint_flag is set to 1.

[0509] When the value of modeTypeCondition is 2, the value of the syntax element mode_constraint_flag is determined using the RDO method. For example, the RD cost generated when inter prediction is performed on all coding units of the current node is first calculated; then, the RD cost generated when intra prediction is performed is calculated; and if there is no residual when inter prediction is performed on all coding units of the current node (e.g., skip mode is used), it is determined that inter prediction is performed on all coding units of the current node, the value of mode_constraint_flag is set to 0, and there is no need to calculate the RD cost generated in the case of intra prediction. Alternatively, the RD cost generated when intra prediction is performed on all coding units of the current node can be calculated first; then, the RD cost generated when inter prediction is performed is calculated; and the prediction mode with the smaller RD cost is determined as the final prediction mode.

[0510] Otherwise, the prediction mode type of all coding units of the current node is not restricted and is the same as the prediction mode type of the current node.

[0511] In particular, if the current node is located in an intra image region (i.e., the type or slice (slice_type) of the image where the current node is of intra type or I type) and the use of IBC mode is allowed, the value of pred_mode_flag defaults to 1. If the current node is located in an intra image region but the use of IBC mode is not allowed, the value of pred_mode_flag defaults to 1 and the value of cu_skip_flag defaults to 0.

[0512] Step 604: Determine the partition mode of the chroma block and the partition mode of the luma block corresponding to the current node to obtain the chroma coding unit and the luma coding unit.

[0513] (Step 604 is the same as step 504).

[0514] Step 605: Predict the coding block of the CU obtained by splitting the current node to obtain a predictor of the coding block.

[0515] If only intra prediction is performed for all coding blocks of the current node, the encoder side determines the optimal intra prediction mode to be used for the current coding block according to a rate-distortion optimization (RDO) method or another method; then predicts the current coding block using the corresponding intra prediction mode to obtain a predictor for the current block.

[0516] If only inter prediction is performed for all coding blocks of the current node, the encoder side determines the optimal inter prediction mode to be used for the current coding block according to a rate-distortion optimization method or another method; and then predicts the current coding block using the corresponding inter prediction mode to obtain a predictor for the current block.

[0517] Furthermore, the encoder assigns values ​​to CU depth-related syntax elements and writes the values ​​of each syntax element to the bitstream according to the criteria of the CU-level syntax specification. For example, if only intra prediction is performed for all coding blocks of the current node, the value of pred_mode_flag is set to 1, and pred_mode_flag is not written to the bitstream. That is, pred_mode_flag does not exist in the bitstream. If it is determined that only intra prediction is performed for all coding blocks of the current node and the IBC mode is not used, the value of cu_skip_flag (or skip_flag) is 0, and cu_skip_flag is not written to the bitstream. In other words, if it is determined that only intra prediction is performed for all coding blocks of the current node and the IBC mode is not used, the value of cu_skip_flag (or skip_flag) is 0, and cu_skip_flag is not written to the bitstream. In other cases, after determining the value of cu_skip_flag, cu_skip_flag needs to be written to the bitstream, and the cu_skip_flag is transmitted to the decoder side.

[0518] When only inter prediction is performed for all coding blocks of the current node, the value of pred_mode_flag is set to 0, and pred_mode_flag is not written to the bitstream. That is, pred_mode_flag is not present in the bitstream. When the value of pred_mode_ibc_flag is set to 0, pred_mode_ibc_flag is not written to the bitstream. That is, pred_mode_ibc_flag is not present in the bitstream.

[0519] Step 606: Obtain the reconstructed signal of the image block at the current node.

[0520] After obtaining prediction information through intra prediction or inter prediction, the encoder obtains residual information by subtracting corresponding prediction information (or predictor) from pixel values ​​of pixels in the current coding block, transforms the residual information using a method such as Discrete Cosine Transform (DCT), obtains a bitstream through quantization and entropy coding, and transmits the residual information to the decoder. After adding the prediction signal and the reconstructed residual signal, the encoder must further perform a filtering operation to obtain a reconstructed signal, which is used as a reference signal for subsequent encoding. In particular, when skip mode is used for a coding block, there is no residual information, so there is no need to perform transformation on the encoder side, and the predictor becomes the final reconstructed value.

[0521] 15 is a schematic structural diagram of the functions of an image prediction device according to an embodiment of the present application. As shown in FIG. 15, the image prediction device 40 provided in this embodiment includes: an acquisition module 41 configured to acquire the partition mode of the current node; a determining module 42 configured to determine whether an image block having a preset size is obtained by dividing a current node in a division mode, the image block including a luma block or a chroma block; an execution module 43 configured to perform intra prediction or inter prediction on all coding blocks covered by the current node when it is determined that an image block having a preset size is obtained by dividing the current node in the division mode;

[0522] Optionally, the image block having the preset size includes a luma block having a first preset size, and the determination module 42 is particularly configured to determine, based on the size of the current node and the partitioning mode of the current node, whether the luma block having the first preset size is obtained by partitioning the current node in the partitioning mode.

[0523] Optionally, when it is determined that a luma block having a first preset size is obtained by splitting the current node in the split mode, the execution module 43 is particularly configured to perform intra prediction on all coding blocks covered by the current node.

[0524] Optionally, when a luma block having a first preset size is not obtained by dividing the current node in the split mode, the determining module 42 is further configured to determine whether a chroma block having a second preset size is obtained by dividing the current node in the split mode; When it is determined that a chroma block having a second preset size is obtained by splitting the current node in the split mode, the execution module 43 is particularly configured to perform intra prediction or inter prediction on all coding blocks covered by the current node.

[0525] Optionally, the image block having the preset size includes a chroma block having a second preset size, and the determination module 42 is particularly configured to determine, based on the size of the current node and the splitting mode of the current node, whether the chroma block having the second preset size is obtained by splitting the current node in the splitting mode.

[0526] Optionally, when it is determined that a chroma block having a second preset size is obtained by splitting the current node in the split mode, the execution module 43: Parsing the prediction mode status flag of the current node; and The node is particularly configured to: perform inter prediction for all coding blocks covered by the current node when the value of the prediction mode status flag is a first value; or perform intra prediction for all coding blocks covered by the current node when the value of the prediction mode status flag is a second value.

[0527] Optionally, when it is determined that a chroma block having a second preset size is obtained by splitting the current node in the split mode, the execution module 43 is particularly configured to perform inter prediction on all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is inter prediction; or to perform intra prediction on all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is intra prediction.

[0528] Optionally, the given coding block is the first coding block among all coding blocks covered by the current node in decoding order.

[0529] Optionally, when it is determined that a chroma block having a second preset size is obtained by splitting the current node in the split mode, the execution module 43: Determining whether a luma block having a first preset size is obtained by dividing the current node in a division mode; and It is particularly configured to perform intra prediction for all coding blocks covered by the current node when it is determined that a luma block having a first preset size is obtained by splitting the current node in the split mode.

[0530] Optionally, when it is determined that a luma block having the first preset size is not obtained by splitting the current node in the split mode, the execution module 43: Parsing the prediction mode status flag of the current node; and It is particularly configured to: perform inter prediction for all coding blocks covered by the current node when the value of the prediction mode status flag is a first value; or perform intra prediction for all coding blocks covered by the current node when the value of the prediction mode status flag is a second value.

[0531] Optionally, when it is determined that a luma block having the first preset size is not obtained by splitting the current node in the split mode, the execution module 43: It is particularly configured to: perform inter prediction for all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is inter prediction; or perform intra prediction for all coding blocks covered by the current node if the prediction mode used for any coding block covered by the current node is intra prediction.

[0532] Optionally, the execution module 43 In a split mode, splitting a luma block included in the current node to obtain a luma block obtained by splitting, and performing intra prediction on the luma block obtained by splitting; and using a chroma block included in the current node as a chroma coding block, and performing intra prediction on the chroma coding block; or The node is particularly configured to: in a split mode, split a luma block included in the current node to obtain a luma block obtained by the split, and perform inter prediction on the luma block obtained by the split; and in a split mode, split a chroma block included in the current node to obtain a chroma block obtained by the split, and perform inter prediction on the chroma block obtained by the split.

[0533] Optionally, the execution module 43 In a split mode, splitting a luma block included in the current node to obtain a luma block obtained by splitting, and performing intra prediction on the luma block obtained by splitting; and using a chroma block included in the current node as a chroma coding block, and performing intra prediction on the chroma coding block; or In a split mode, the node is particularly configured to split a luma block included in the current node to obtain a luma block obtained by the split, and perform inter prediction on the luma block obtained by the split; and to use a chroma block included in the current node as a chroma coding block, and perform inter prediction on the chroma coding block.

[0534] Optionally, when inter prediction is performed for all coding blocks covered by the current node, the obtaining module 41 is further configured to obtain a partitioning sub-mode of a child node of the current node, where the child node includes a luma block and a chroma block; and The determining module 42 is further configured to determine whether a luma block having a first preset size is obtained by dividing a child node of the current node in the division submode; and When it is determined that a luma block having a first preset size is obtained by splitting the child node of the current node in the split sub-mode, the execution module 43 is particularly configured to: split the child node of the current node in a split mode other than the split sub-mode to obtain a corresponding coding block and perform inter prediction on the corresponding coding block; or use the child node of the current node as a coding block and perform inter prediction on the coding block.

[0535] The image prediction device provided in this embodiment of the present application can implement the technical solutions in the above-mentioned method embodiments, and the implementation principles and their technical effects are similar, so the details will not be described again here.

[0536] 16 is a schematic structural diagram of the hardware of a video encoding device according to an embodiment of the present application. As shown in FIG. 16, the video encoding device 50 provided in this embodiment includes a processor 51 and a memory 52 configured to store executable instructions for the processor 51. The processor 51 can execute an image prediction method corresponding to the video encoding device in the above-mentioned method embodiment. The implementation principle and its technical effect are similar, and the details will not be described again here.

[0537] Optionally, the memory 52 may be separate or integrated with the processor 51 .

[0538] In the case where the memory 52 is a separate component from the processor 51 , the video encoding device 50 further includes a bus 53 configured to connect the memory 52 and the processor 51 .

[0539] 17 is a schematic structural diagram of the hardware of a video decoding device according to an embodiment of the present application. As shown in FIG. 17, the video decoding device 60 provided in this embodiment includes a processor 61 and a memory 62 configured to store executable instructions for the processor 61. The processor 61 can execute an image prediction method corresponding to the video decoding device in the above-mentioned method embodiment. The implementation principle and its technical effect are similar, and the details will not be described again here.

[0540] Optionally, memory 62 may be separate or integrated with processor 61 .

[0541] In the case where the memory 62 is a separate component from the processor 61 , the video decoding device 60 further includes a bus 63 configured to connect the memory 62 and the processor 61 .

[0542] Figure 18 is a schematic structural diagram of an image prediction system according to an embodiment of the present application. As shown in Figure 18, the image prediction system provided in this embodiment includes a video acquisition device 70, a video encoding device 50 of the embodiment shown in Figure 16, a video decoding device 60 of the embodiment shown in Figure 17, and a display device 80.

[0543] The video encoding device 50 is connected to both a video acquisition device 70 and a video decoding device 60 , which is connected to a display device 80 .

[0544] Specifically, the video encoding device 50 receives video or image information transmitted by the video acquisition device 70. The video encoding device 50 may perform an image prediction method corresponding to the video encoding device 50 in the method embodiments described above. The video encoding device 50 transmits the encoded video or image information to the video decoding device 60. The video decoding device 60 may perform an image prediction method corresponding to the video decoding device 60 in the method embodiments described above. The video decoding device 60 transmits the decoded video or image information to the display device 80 for display.

[0545] The image prediction system provided in this embodiment of the present application includes a video encoding device that can implement the above-mentioned method embodiment and a video decoding device that can implement the above-mentioned method embodiment. The implementation principle and its technical effect are similar, and the details will not be described again here.

[0546] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program, which is executed by a processor to perform the steps in the above-described method embodiments.

[0547] An embodiment of the present application further provides a video decoding method, the method comprising: obtaining a split mode of a current node, where the current node includes a luma block and a chroma block; determining whether a small chroma block is obtained by further dividing the current node in a division mode of the current node, where the small chroma block is a chroma block having a pixel quantity equal to or less than a first preset value, or the small chroma block is a block-by-block chroma block having a pixel quantity equal to or less than a second preset value; When a small chroma block is obtained by further dividing the current node in the division mode of the current node, the method includes a step of performing inter prediction or intra prediction on the coding block obtained by dividing the current node that serves as the root node to obtain prediction information of the coding block obtained by the division.

[0548] Optionally, performing inter prediction on coding blocks obtained by dividing the current node serving as the root node comprises performing inter prediction on all coding blocks obtained by dividing the current node serving as the root node; or The step of performing intra prediction on coding blocks obtained by dividing the current node that serves as the root node includes the step of performing intra prediction on all coding blocks obtained by dividing the current node that serves as the root node.

[0549] Optionally, performing inter prediction on coding blocks obtained by dividing the current node serving as the root node includes performing inter prediction on all small chroma blocks obtained by dividing the current node serving as the root node; or The step of performing intra prediction on coding blocks obtained by dividing the current node that serves as the root node includes the step of performing intra prediction on all small chroma blocks obtained by dividing the current node that serves as the root node.

[0550] Optionally, performing inter prediction on coding blocks obtained by splitting the current node serving as the root node comprises performing inter prediction on coding units obtained by splitting the current node serving as the root node; or The step of performing intra prediction on a coding block obtained by dividing the current node that serves as the root node includes the step of performing intra prediction on a coding unit obtained by dividing the current node that serves as the root node.

[0551] Optionally, the step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: Parsing the node prediction mode flag (cons_pred_mode_flag) of the current node; and performing inter prediction on a coding block obtained by dividing the current node that serves as a root node when the value of the node prediction mode flag is a first value; or The method includes a step of performing intra prediction on a coding block obtained by dividing the current node that serves as the root node when the value of the node prediction mode flag is a second value.

[0552] Optionally, the step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: performing inter prediction on coding blocks obtained by dividing the current node serving as the root node, if the prediction mode used for any coding blocks obtained by dividing the current node serving as the root node is inter prediction; or The method includes a step of performing intra prediction on a coding block obtained by splitting the current node that serves as the root node, when the prediction mode used for any coding block obtained by splitting the current node that serves as the root node is intra prediction.

[0553] Optionally, the first preset value is 2 or 4, or the second preset value is 16, 8, or 32.

[0554] Optionally, the step of performing intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: In a node split mode, splitting a luma block included in the current node to obtain a luma coding block; performing intra prediction on the luma coding block; using the chroma block included in the current node as a chroma coding block and performing intra prediction on the chroma coding block;

[0555] Optionally, the step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: In a node split mode, splitting a luma block included in the current node to obtain a luma coding block; performing inter prediction or intra prediction on the luma coding block; Using the chroma block included in the current node as a chroma coding block, and performing inter prediction or intra prediction on the chroma coding block;

[0556] Optionally, the step of using the chroma block included in the current node as a chroma coding block and performing inter prediction or intra prediction on the chroma coding block includes: using the chroma coding block as a chroma prediction block and performing intra prediction on the chroma prediction block; or The method includes a step of dividing a chroma coding block to obtain a chroma prediction block, and performing inter prediction on the chroma prediction block obtained by the division.

[0557] An embodiment of the present application further provides a video decoding method, the method comprising: obtaining a split mode of a current node, where the current node includes a luma block and a chroma block; Determining whether a luma block having a preset size can be obtained by further dividing the current node in the division mode of the current node; When a luma block having a predetermined size is obtained by further dividing the current node in the division mode of the current node, performing intra prediction on all coding blocks obtained by dividing the current node serving as the root node, and obtaining prediction blocks of the coding blocks obtained by the division;

[0558] Optionally, this method When a luma block having a preset size is not obtained by further dividing the current node in the division mode of the current node, determining whether a small chroma block is obtained by further dividing the current node in the division mode of the current node, where the small chroma block is a chroma block having a pixel quantity equal to or less than a first preset value, or the small chroma block is a block-by-block chroma block having a pixel quantity equal to or less than a second preset value; The method further includes a step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as the root node to obtain a prediction block of the coding block obtained by the division when a small chroma block is obtained by further dividing the current node in the division mode of the current node.

[0559] Optionally, performing inter prediction on coding blocks obtained by dividing the current node serving as the root node comprises performing inter prediction on all coding blocks obtained by dividing the current node serving as the root node; or The step of performing intra prediction on coding blocks obtained by dividing the current node that serves as the root node includes the step of performing intra prediction on all coding blocks obtained by dividing the current node that serves as the root node.

[0560] Optionally, performing inter prediction on coding blocks obtained by dividing the current node serving as the root node includes performing inter prediction on all small chroma blocks obtained by dividing the current node serving as the root node; or The step of performing intra prediction on coding blocks obtained by dividing the current node that serves as the root node includes the step of performing intra prediction on all small chroma blocks obtained by dividing the current node that serves as the root node.

[0561] Optionally, performing inter prediction on coding blocks obtained by splitting the current node serving as the root node comprises performing inter prediction on coding units obtained by splitting the current node serving as the root node; or The step of performing intra prediction on a coding block obtained by dividing the current node that serves as the root node includes the step of performing intra prediction on a coding unit obtained by dividing the current node that serves as the root node.

[0562] Optionally, the step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: Parsing the node prediction mode flag (cons_pred_mode_flag) of the current node; When the value of the node prediction mode flag is a first value, performing inter prediction on a coding block obtained by dividing the current node serving as a root node; When the value of the node prediction mode flag is a second value, performing intra prediction on a coding block obtained by dividing the current node that serves as the root node.

[0563] Optionally, the step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: performing inter prediction on a coding block obtained by dividing the current node serving as the root node, when a prediction mode used for any coding block obtained by dividing the current node serving as the root node is inter prediction; The method includes a step of performing intra prediction on a coding block obtained by dividing the current node that serves as the root node, when the prediction mode used for any coding block obtained by dividing the current node that serves as the root node is intra prediction.

[0564] Optionally, the first preset value is 2 or 4, or the second preset value is 16, 8, or 32.

[0565] Optionally, the step of performing intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: In a node split mode, splitting a luma block included in the current node to obtain a luma coding block; performing intra prediction on the luma coding block; using the chroma block included in the current node as a chroma coding block and performing intra prediction on the chroma coding block;

[0566] Optionally, the step of performing inter prediction or intra prediction on a coding block obtained by dividing the current node serving as a root node comprises: In a node split mode, splitting a luma block included in the current node to obtain a luma coding block; performing inter prediction or intra prediction on the luma coding block; Using the chroma block included in the current node as a chroma coding block, and performing inter prediction or intra prediction on the chroma coding block;

[0567] Optionally, the step of using the chroma block included in the current node as a chroma coding block and performing inter prediction or intra prediction on the chroma coding block includes: using the chroma coding block as a chroma prediction block and performing intra prediction on the chroma prediction block; or The method includes a step of dividing a chroma coding block to obtain a chroma prediction block, and performing inter prediction on the chroma prediction block obtained by the division.

[0568] Optionally, performing inter prediction on a coding block obtained by dividing the current node serving as a root node comprises: Splitting the current node using the split mode of the current node to obtain a child node of the current node; obtaining a split sub-mode of a child node of a current node, the child node including a luma block and a chroma block; Determining whether a luma block having a preset size can be obtained by further dividing a child node of the current node in a division submode; When a luma block having a predetermined size is obtained by further dividing the child node of the current node in the division sub-mode, the method includes a step of dividing the child node of the current node in a division mode other than the division sub-mode to obtain a corresponding coding unit and performing inter prediction on the corresponding coding unit; or a step of using the child node of the current node as a coding unit and performing inter prediction on the coding unit.

[0569] Optionally, the preset size can be 4x4, 4x8, 8x4, 2x4, or 4x2.

[0570] An embodiment of the present application further provides a video decoding method, the method comprising: obtaining a split mode of a current node, where the current node includes a luma block and a chroma block; When the prediction mode used for all coding blocks obtained by dividing the current node serving as a root node is an inter prediction mode, dividing the current node in the division mode of the current node to obtain a child node of the current node; obtaining a split sub-mode of a child node of a current node, the child node including a luma block and a chroma block; Determining whether a luma block having a preset size can be obtained by further dividing a child node of the current node in a division submode; When a luma block having a predetermined size is obtained by further dividing the child node of the current node in the division sub-mode, the method includes a step of dividing the child node of the current node in a division mode other than the division sub-mode to obtain a corresponding coding unit and performing inter prediction on the corresponding coding unit; or a step of using the child node of the current node as a coding unit and performing inter prediction on the coding unit.

[0571] The first video decoding method provided in this embodiment of the present application relates to a block division mode in video decoding. The video data format in this embodiment is YUV4:2:0 format. The same method can also be used for data in YUV4:2:2 format.

[0572] Step 1: Analyze the split mode S of node A. If node A is to be further split, step 2 is performed. If the current node is not to be further split into child nodes, the current node corresponds to one coding unit, and information about the coding unit is analyzed.

[0573] The partitioning mode of node A may be at least one of quadtree partitioning, vertical binary tree partitioning, horizontal binary tree partitioning, vertical ternary tree partitioning, and horizontal ternary tree partitioning. The partitioning mode may also be another partitioning mode. This is not limited to this application. Information about the partitioning mode of the current node may be transmitted in the bitstream. The partitioning mode of the current node can be obtained by analyzing a corresponding syntax element in the bitstream. Alternatively, the partitioning mode of the current node may be determined according to a preset rule. This is not limited to this application.

[0574] Step 2: Determine whether the chroma block of at least one child node B in the child node obtained by splitting node A in split mode S is a small block (by determining whether the width and height of node A, and / or the split mode of node A, and / or the width and height of node B satisfy at least one of the following conditions). If the chroma block of at least one child node B in the child node obtained by splitting node A is a small block, steps 3 to 6 are performed.

[0575] Specifically, whether a chroma block of at least one child node B of node A is a small block may be determined according to one of the following methods: (1) If the size of the chroma block of at least one child node B of node A is 2×2, 2×4, or 4×2, the chroma block of at least one child node B of node A is a small block; (2) If the width or height of the chroma block of at least one child node B of node A is 2, the chroma block of at least one child node B of node A is a small block; (3) When node A contains 128 luma pixels and ternary tree partitioning is used for node A, or when node A contains 64 luma pixels and binary tree partitioning, quad tree partitioning, or ternary tree partitioning is used for node A, the chroma block of at least one child node B of node A is a small block; (4) When node A contains 256 luma pixels and ternary tree or quad-tree partitioning is used for node A, or when node A contains 128 luma pixels and binary tree partitioning is used for node A, the chroma block of at least one child node B of node A is a small block; (5) When node A contains N1 luma pixels and ternary tree division is used for node A (N1 is 64, 128, or 256), the chroma block of at least one child node B of node A is a small block; (6) If node A contains N luma pixels and quadtree partitioning is used for node A (N is 64 or 256), the chroma block of at least one child node B of node A is a small block; or (7) If node A contains N3 luma pixels and binary tree partitioning is used for node A (N3 is 64, 128, or 256), the chroma block of at least one child node B of node A is a small block.

[0576] Note that node A containing 128 luma pixels can also be described as the area of ​​the current node being 128, or the product of the width and height of node A being 128. Details will not be described here.

[0577] Step 3: Restrict node A from performing intra prediction for all coding units within its coverage area, or restrict node A from performing inter prediction for all coding units within its coverage area. Since intra prediction or inter prediction is performed for all coding units within node A's coverage area, hardware small block parallel processing can be implemented, thereby improving coding performance.

[0578] Whether to perform intra prediction or inter prediction for all coding units within the coverage area of ​​node A may be determined according to one of the following methods.

[0579] Method 1: Determine whether intra or inter prediction is performed based on a flag in the syntax table.

[0580] If the chroma blocks of at least one child node B obtained by splitting node A in split mode S are small blocks (and the chroma blocks of node A are not small blocks), the flag cons_pred_mode_flag is parsed from the bitstream. If the value of cons_pred_mode_flag is 0, it indicates that inter prediction is performed for all coding units in the coverage area of ​​node A, or if the value of cons_pred_mode_flag is 1, it indicates that intra prediction is performed for all coding units in the coverage area of ​​node A. cons_pred_mode_flag may be a syntax element that needs to be parsed during block splitting. If the syntax element is parsed, the cu_pred_mode of the coding units in the coverage area of ​​node A may not be parsed, and the value of cu_pred_mode is a default value corresponding to the value of cons_pred_mode_flag.

[0581] When only intra prediction mode is used for the child nodes of node A, for example, when node A is located in an intra image (i.e., the type of the image where node A is located is intra type or I type), or when node A is located in an intra image and IBC technology is not used in the sequence, the value of cons_pred_mode_flag is 1 by default, that is, cons_pred_mode_flag is not present in the bitstream. The IBC technology may belong to inter prediction or intra prediction.

[0582] Method 2: Determine whether intra prediction or inter prediction is performed based on the prediction mode of the first node in the region of node A.

[0583] The prediction mode of the first coding unit B0 in the coverage area of ​​node A (the prediction mode of the first coding unit B0 is not limited) is analyzed. If the prediction mode of the first coding unit B0 is intra prediction, intra prediction is performed for all coding units in the coverage area of ​​node A. If the prediction mode of the first coding unit B0 is inter prediction, inter prediction is performed for all coding units in the coverage area of ​​node A.

[0584] Step 4: Determine the partition mode of the chroma blocks and the partition mode of the luma blocks of node A based on the prediction modes used for the coding units in the coverage area of ​​node A.

[0585] When intra prediction mode is used for all coding units within the coverage area of ​​node A, the luma block of node A is split using split mode S to obtain N luma coding tree nodes. The chroma block of node A is not split any further and corresponds to one chroma coding block (chroma CB for short). The N luma coding tree nodes may be restricted to not being split any further, or this is not restricted. When the luma child node is further split, the split mode of the luma child node is analyzed for recursive splitting. When the luma coding tree node is not split any further, the luma coding tree node corresponds to one luma coding block (luma CB for short). The chroma transform block and chroma coding block corresponding to the chroma CB are the same size, and the chroma prediction block and chroma coding block are the same size.

[0586] If inter prediction mode is used for all coding units within the coverage area of ​​node A, the luma blocks and chroma blocks of node A are further divided into N coding tree nodes in partition mode S, where the coding tree nodes include luma blocks and chroma blocks. The N coding tree nodes may or may not be further divided. In the absence of further division, the N coding tree nodes correspond to coding units that include luma blocks and chroma blocks.

[0587] Step 5: Analyze the prediction information and residual information of the CU obtained by splitting node A.

[0588] The prediction information includes a prediction mode (indicating an intra prediction mode or a non-intra prediction mode), an intra prediction mode, an inter prediction mode, motion information, etc. The motion information may include information such as a prediction direction (forward, backward, or bidirectional), a reference index, and a motion vector.

[0589] The residual information includes coded block flags (cbf), transform coefficients, transform type (DCT-2, DCT-7, or DCT-8, etc.), etc. The transform type may be DCT-2 by default.

[0590] When all CUs obtained by splitting node A are restricted to performing only intra prediction, analyzing prediction information of luma CB obtained by splitting node A includes: setting the value of skip_flag, the value of merge_flag, and the value of cu_pred_mode to 0, 0, and 1 by default, respectively (i.e., skip_flag, merge_flag, and cu_pred_mode are all absent in the bitstream); or setting the value of skip_flag and the value of cu_pred_mode to 0 and 1 by default, respectively (i.e., skip_flag and cu_pred_mode are both absent in the bitstream); and analyzing information about the intra prediction mode of the luma CB. Analyzing prediction information of chroma CB obtained by splitting node A includes analyzing the intra prediction mode of the chroma CB. The intra prediction mode of the chroma CB can be analyzed according to the following method: (1) Parsing syntax elements in the bitstream to obtain intra-prediction modes; or (2) In a set of chroma intra prediction modes such as a linear model mode, a chroma derived mode (DM) mode, and an IBC mode, the intra prediction mode is directly set to one intra prediction mode.

[0591] When all CUs obtained by splitting node A are restricted to performing only inter prediction, the step of analyzing the prediction mode of the CUs obtained by splitting node A includes the steps of analyzing skip_flag and / or merge_flag, setting the cu_pred_mode value to 0 by default, and analyzing inter prediction information such as merge index, inter direction, reference index, motion vector predictor index, and motion vector difference.

[0592] skip_flag represents a skip mode flag. When the value of skip_flag is 1, it indicates that skip mode is used for the current CU, or when the value of skip_flag is 0, it indicates that skip mode is not used for the current CU. merge_flag is a merge mode flag. When the value of merge_flag is 1, it indicates that merge mode is used for the current CU, or when the value of merge_flag is 0, it indicates that merge mode is not used for the current CU. cu_pred_mode represents a prediction mode flag of the coding unit. When the value of cu_pred_mode is 1, it indicates that intra prediction is performed for the current prediction unit, or when the value of cu_pred_mode...

Claims

1. 1. A method of image prediction, the method comprising: obtaining a prediction mode state flag of a current node when a preset condition is satisfied, the current node being a coding tree unit in a current image; performing inter prediction on a coding unit belonging to the current node to obtain a predictor of the coding unit belonging to the current node when the value of the prediction mode state flag is a first value, or performing intra prediction on the coding unit belonging to the current node to obtain the predictor of the coding unit belonging to the current node when the value of the prediction mode state flag is a second value; obtaining a coding unit prediction mode flag indicating a prediction mode of a current coding unit based on the value of the prediction mode state flag; method.

2. The method of claim 1 , wherein the coding unit prediction mode flag is represented as pred_mode_flag.

3. The method of claim 1 or 2, wherein the coding unit prediction mode flag is not included in the bitstream.

4. The method of claim 1 , wherein the predetermined condition is determined based on a splitting mode of the current node, a size of the current node, and a chroma format of the current node.

5. The method of claim 4 , wherein the preset conditions include: a number of samples in a luma block of the current node is 64; and the partitioning mode of the current node is binary tree partitioning.

6. The method of claim 4 , wherein the preset conditions include: a luma block sample number of the current node is 128; and the partitioning mode of the current node is ternary tree partitioning.

7. The method of claim 4 , wherein the chroma format of the current node is YUV4:2:0 or YUV4:2:

2.

8. The preset conditions include: The number of samples of the luma block of the current node is 64, the partitioning mode of the current node is binary tree partitioning, and the chroma format of the current node is 4:2:0; or 5. The method of claim 4, further comprising at least one of: the number of samples of the luma block of the current node is 128; the partitioning mode of the current node is ternary tree partitioning; and the chroma format of the current node is 4:2:

0.

9. The method of claim 1 , wherein the prediction mode state flag of the current node is obtained from a bitstream if the preset condition is met.

10. 1. A video coding apparatus, comprising: a processor; a memory coupled to the processor for storing executable instructions; The executable instructions, when executed by the processor, cause the processor to perform the following actions: The operation includes: Obtaining a prediction mode state flag of a current node when a preset condition is met, the current node being a coding tree unit in a current image; and performing inter prediction on a coding unit belonging to the current node to obtain a predictor for the coding unit belonging to the current node when the value of the prediction mode state flag is a first value; or performing intra prediction on the coding unit belonging to the current node to obtain the predictor for the coding unit belonging to the current node when the value of the prediction mode state flag is a second value; obtaining a coding unit prediction mode flag indicating a prediction mode of a current coding unit based on the value of the prediction mode state flag; Video coding device.

11. The video coding apparatus of claim 10 , wherein the coding unit prediction mode flag is represented as pred_mode_flag.

12. The video coding apparatus according to claim 10 or 11, wherein the coding unit prediction mode flag is not included in the bitstream.

13. The video coding device according to claim 10 , wherein the predetermined condition is determined based on a division mode of the current node, a size of the current node, and a chroma format of the current node.

14. The video coding apparatus of claim 13 , wherein the predetermined conditions include: a number of samples of a luma block of the current node is 64; and the partitioning mode of the current node is binary tree partitioning.

15. The video coding apparatus of claim 13 , wherein the predetermined conditions include: a number of samples of a luma block of the current node is 128; and the partitioning mode of the current node is ternary tree partitioning.

16. The video coding apparatus of claim 13 , wherein the chroma format of the current node is YUV 4:2:0 or YUV 4:2:

2.

17. The preset conditions include: The number of samples of the luma block of the current node is 64, the partitioning mode of the current node is binary tree partitioning, and the chroma format of the current node is 4:2:0; or 14. The video coding device of claim 13, wherein at least one of the following is included: the number of samples of the luma block of the current node is 128; the partitioning mode of the current node is ternary tree partitioning; and the chroma format of the current node is 4:2:

0.

18. The video coding device of claim 10 , wherein the prediction mode state flag of the current node is obtained from a bitstream if the preset condition is met.

19. 1. A non-transitory storage medium for storing a bitstream including compressed video data and one or more syntax elements used as instructions describing how to process the compressed video data to reconstruct a picture, the instructions being executable by a video decoding device, the bitstream including: a prediction mode state flag of a current node, which is a coding tree unit in a current image, when a preset condition is satisfied; a partition mode of the current node; When the value of the prediction mode state flag is a first value, inter prediction is performed on a coding unit belonging to the current node, and a predictor of the coding unit belonging to the current node is obtained; or when the value of the prediction mode state flag is a second value, intra prediction is performed on a coding unit belonging to the current node, and the predictor of the coding unit belonging to the current node is obtained; obtaining a coding unit prediction mode flag indicating a prediction mode of a current coding unit based on the value of the prediction mode state flag; Non-transitory storage media.

20. The non-transitory storage medium of claim 19 , wherein the coding unit prediction mode flag is represented as pred_mode_flag and is not included in the bitstream.

Images