Method and device for intra smoothing

Abstract

To provide device and method for intra prediction of blocks of a picture.SOLUTION: A method includes a step of obtaining intra-subdivision (ISP) information, the ISP information indicating whether the ISP is used to divide a current block, and a step of selecting a set of coefficients of an interpolation filter based on the ISP information, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients. The method further includes a step of obtaining a predicted sample of the current block by applying the set of coefficients to a reference sample. When the ISP information indicates whether the ISP is used to divide the current block (i.e., the ISP is on), the method removes mode dependency during the selection of the type of the interpolation filter. This can enhance the efficiency of encoding or decoding.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 62 / 825,793, filed March 28, 2019, which is incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE Embodiments of the present application (disclosure) relate generally to the field of picture processing, and more particularly to methods and apparatus for intra prediction, and in particular, intra smoothing. [Background technology]

[0003] Video coding (video encoding and decoding) is used in a wide range of digital video applications, e.g., broadcast digital TV, video transmission over the Internet and mobile networks, real-time conversation applications such as video chat, video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems, and camcorders in security applications.

[0004] The amount of video data required to depict even a relatively short video can be significant, which can pose difficulties when the data is to be streamed or otherwise conveyed over a communication network with limited bandwidth capacity. Thus, video data is generally compressed before being conveyed over modern communication networks. The size of the video can also be an issue when the video is stored in a storage device, since memory resources may be limited. Often, video compression devices use software and / or hardware at the source to code the video data before transmission or storage, thereby reducing the amount of data required to represent a digital video image. The compressed data is then received at the destination by a video decompression device, which decodes the video data. With limited network resources and an ever-increasing demand for higher video quality, improved compression and decompression techniques that increase compression ratios with little or no sacrifice in picture quality are desirable. Summary of the Invention [Means for solving the problem]

[0005] Embodiments of the present application provide apparatus and methods for encoding and decoding according to the independent claims.

[0006] These and other objects are achieved by the subject matter of the independent claims. Further implementation forms are evident from the dependent claims, the description and the drawings.

[0007] A first aspect of the present invention relates to a method for intra prediction of a block of a picture, the method including the steps of obtaining Intra Partition (ISP) information, the ISP information indicating whether the ISP is used to divide a current block, and selecting a set of coefficients of an interpolation filter based on the ISP information, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients. The method further includes obtaining a predicted sample of the current block by applying the set of coefficients to a reference sample.

[0008] As an implementation of the first aspect, the information of the ISP may be indicated by IntraSubPartitionsSplitType. When IntraSubPartitionsSplitType != ISP_NO_SPLIT, the ISP is used to split the current block (that is, the ISP is on).

[0009] As an implementation of the first aspect, when the information of the ISP indicates that the ISP is used to split the current block, the filtering state of the block is a no-smoothing state. The filtering state of the block may be determined by a flag smoothState, and the filtering state of the block is a no-smoothing state when the value of smoothState is 0. The value of filterFlag is equal to the value of smoothState, i.e., 0. Correspondingly, the fC coefficient is selected.

[0010] A second aspect of the present invention relates to a method for intra prediction of a block of a picture, the method comprising the steps of detecting a filtering state of the block (i.e., a smoothing state of the block) based on information in a sub-partition (ISP), the filtering state of the block comprising a no-smoothing state, a smoothing state, or a direction-dependent smoothing state, and selecting a set of coefficients of an interpolation filter based on the value of the filtering state of the block, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients. The method further comprises the step of obtaining a predicted sample of the current block by applying the set of coefficients to a reference sample.

[0011] As an implementation of the second aspect, the ISP information may be indicated by IntraSubPartitionsSplitType. When IntraSubPartitionsSplitType != ISP_NO_SPLIT, the ISP is used to split the current block (i.e., the ISP is on). When the ISP information indicates that the ISP is used to split the current block, the filtering state of the block is the no-smooth state. The filtering state of the block may be determined by a flag smoothState, and the filtering state of the block is the no-smooth state when the value of smoothState is 0.

[0012] As an implementation of the second aspect, a value of filterFlag may be used to indicate that a set of coefficients of the interpolation filter is fG coefficients or fC coefficients. The value of filterFlag is equal to the value of smoothState, which means that when the filtering state of the block is in a no smoothing state, the value of filterFlag is 0. Correspondingly, the fC coefficients are selected.

[0013] A third aspect of the invention relates to a method of intra prediction of a block of a picture, the method comprising a step of obtaining predicted samples of the block by applying an interpolation filter to reference samples, a set of coefficients of which are obtained by the following steps performed for each of the smoothing mechanisms: - obtaining a value of a flag indicating whether an intra prediction mechanism is applied; and - comparing the value of the obtained flag (e.g., intraSubPartitionSplitType) with a given binary value (e.g., ISP_NO_SPLIT); The decision is based on a judgment (also called the "block filtering state") that includes: The determination of the set of coefficients is performed by selecting one of a predetermined set of coefficients, the selection being based on a decision that is the result of a comparison of the obtained flag value with a predetermined binary value.

[0014] The method according to the first aspect of the present invention may be performed by a device according to the fourth aspect of the present invention. The device includes an acquisition unit, a selection unit, and a prediction unit. The acquisition unit is configured to acquire information in a sub-partition (ISP), the information of the ISP indicating whether the ISP is used to split a current block. The selection unit is configured to select a set of coefficients of an interpolation filter based on the information of the ISP, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients. The prediction unit is configured to acquire a predicted sample of the current block by applying the set of coefficients to a reference sample.

[0015] The method according to the second aspect of the present invention may be executed by a device according to the fifth aspect of the present invention. The device includes a detection unit, a selection unit, and a prediction unit. The detection unit is configured to detect a state of filtering of the block based on information in a sub-partition (ISP), the state of filtering of the block including a no smoothing state, a smoothing state, or a direction-dependent smoothing state. The selection unit is configured to select a set of coefficients of an interpolation filter based on a value of the state of filtering of the block, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients. The prediction unit is configured to obtain a predicted sample of the current block by applying the set of coefficients to a reference sample. Further features and implementation forms of the method according to the second aspect of the present invention correspond to those of the device according to the fifth aspect of the present invention.

[0016] The method according to the third aspect of the invention may be performed by a device according to the sixth aspect of the invention. Further features and implementations of the method according to the third aspect of the invention correspond to the features and implementations of the apparatus according to the sixth aspect of the invention.

[0017] According to a seventh aspect, the invention relates to an apparatus for decoding a video stream, comprising a processor and a memory, the memory storing instructions causing the processor to carry out a method according to the first, second or third aspect or any possible implementation of the first, second or third aspect.

[0018] According to an eighth aspect, the invention relates to an apparatus for encoding a video stream, comprising a processor and a memory, the memory storing instructions causing the processor to carry out a method according to the first, second or third aspect or any possible implementation of the first, second or third aspect.

[0019] According to a ninth aspect, a computer-readable storage medium is proposed having stored thereon instructions which, when executed, cause one or more processors configured to code video data, the instructions causing the one or more processors to perform a method according to the first, second or third aspect or any possible implementation of the first, second or third aspect.

[0020] According to a tenth aspect, the invention relates to a computer program comprising a program code for performing the method according to the first, second or third aspect or any possible implementation of the first, second or third aspect, when the computer program is executed on a computer.

[0021] As discussed above, when the ISP information indicates whether the ISP is used to split the current block (i.e., the ISP is on), the embodiment or implementation of the embodiment removes mode dependency during the selection of the type of interpolation filter, which can improve the efficiency of encoding or decoding.

[0022] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description, drawings, and claims.

[0023] In the following, embodiments of the invention are explained in more detail with reference to the accompanying figures and drawings. [Brief description of the drawings]

[0024] [Figure 1A] 1 is a block diagram illustrating an example of a video coding system configured to implement embodiments of the present invention. [Figure 1B] 2 is a block diagram illustrating another example of a video coding system configured to implement embodiments of the present invention. [Diagram 2] FIG. 2 is a block diagram illustrating an example of a video encoder configured to implement embodiments of the present invention. [Diagram 3] 2 is a block diagram illustrating an exemplary structure of a video decoder configured to implement embodiments of the present invention. [Figure 4] FIG. 2 is a block diagram showing an example of an encoding device or a decoding device. [Diagram 5] FIG. 13 is a block diagram showing another example of an encoding device or a decoding device. [Figure 6] FIG. 2 is a diagram of a two-subdivision partition in an ISP tool. [Figure 7] A diagram of four subdivisions in the ISP tool. [Figure 8] FIG. 1 is an illustration of multi-reference line intra prediction. [Figure 9] A diagram showing a reference sample selection method for PLANAR intra-prediction mode. [Figure 10] A diagram showing a reference sample selection method for PLANAR intra-prediction mode. [Figure 11] A diagram showing a reference sample selection method for PLANAR intra-prediction mode. [Figure 12] FIG. 13 is a diagram illustrating a reference sample selection method for DC intra-prediction modes. [Figure 13] FIG. 13 is a diagram illustrating a reference sample selection method for DC intra-prediction modes. [Figure 14] FIG. 11 is a block diagram showing an example of selection of the type of interpolation filter. [Figure 15] FIG. 13 is a block diagram showing another example of selection of the type of interpolation filter. [Figure 16] FIG. 16 illustrates an embodiment of a method 1600 according to the present invention. [Figure 17] FIG. 17 illustrates an embodiment of a method 1700 in accordance with the present invention. [Figure 18] FIG. 18 illustrates an embodiment of a device 1800 for use in accordance with the present invention. [Figure 19] FIG. 19 illustrates an embodiment of a device 1900 for use in accordance with the present invention. [Figure 20]31 is a block diagram showing an exemplary structure of a content delivery system 3100 for implementing a content distribution service. [Figure 21] FIG. 2 is a block diagram illustrating the structure of an example terminal device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In the following, the same reference signs refer to identical or at least functionally equivalent features, unless otherwise stated.

[0026] In the following description, reference is made to the accompanying drawings which form a part of this disclosure and which show by way of example certain aspects of embodiments of the invention or in which embodiments of the invention may be used. It is understood that embodiments of the invention may be used in other ways and may include structural or logical changes not shown in the drawings. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0027] For example, it is understood that disclosure related to a described method may also apply to a corresponding device or system configured to perform the method, and vice versa. For example, when one or more particular method steps are described, the corresponding device may include one or more units, e.g., functional units, for performing the described one or more method steps (e.g., one unit performing one or more steps, or multiple units each performing one or more of the multiple steps), even if such one or more units are not explicitly described or shown in the figures. On the other hand, for example, when a particular apparatus is described based on one or more units, e.g., functional units, the corresponding method may include one step for performing the function of the one or more units (e.g., one step performing the function of the one or more units, or multiple steps each performing one or more of the functions of the multiple units), even if such one or more steps are not explicitly described or shown in the figures. Furthermore, it is understood that features of various exemplary embodiments and / or aspects described herein may be combined with each other unless expressly stated otherwise.

[0028] Video coding generally refers to the processing of a sequence of pictures forming a video or a video sequence. Instead of the term "picture", the terms "frame" or "image" may be used synonymously in the field of video coding. Video coding (or generally coding) includes two parts: video encoding and video decoding. Video encoding is performed at the source side and generally involves processing an original video picture (e.g., by compression) to reduce the amount of data required to represent the video picture (for more efficient storage and / or transmission). Video decoding is performed at the destination side and generally involves the reverse processing compared to the encoder to reconstruct the video picture. The embodiments referring to "coding" of a video picture (or generally pictures) are understood to relate to "encoding" or "decoding" of the video picture or the respective video sequence. The combination of the encoding and decoding parts is also called a codec (coding and decoding).

[0029] In the case of lossless video coding, the original video picture can be reconstructed (assuming there is no transmission loss or other data loss during storage or transmission), i.e. the reconstructed video picture has the same quality as the original video picture. In the case of lossy video coding, further compression, e.g. by quantization, is performed to reduce the amount of data representing the video picture, which cannot be completely reconstructed at the decoder, i.e. the quality of the reconstructed video picture is lower or worse than the quality of the original video picture.

[0030] Some video coding standards belong to the group of "lossy hybrid video codecs" (i.e., they combine spatial and temporal prediction in the sample domain with 2D transform coding to apply quantization in the transform domain). Each picture of a video sequence is generally partitioned into a set of non-overlapping blocks, and coding is generally performed at the block level. In other words, in an encoder, a video is generally processed, i.e., encoded, at the block (video block) level, for example, by generating a prediction block using spatial (intra-picture) prediction and / or temporal (inter-picture) prediction, subtracting the prediction block from a current block (currently being / to be processed block) to obtain a residual block, transforming the residual block, and quantizing the residual block in the transform domain to reduce the amount of data to be transmitted (compression), while in a decoder, a reverse process is applied to the coded or compressed block compared to the encoder in order to reconstruct the current block for representation. Furthermore, the encoder replicates the decoder's processing loop so that both generate the same prediction (eg, intra- and inter-prediction) and / or reconstruction for processing, i.e., coding, subsequent blocks.

[0031] In the following, embodiments of a video coding system 10, a video encoder 20 and a video decoder 30 are described based on FIGS.

[0032] 1A is a schematic block diagram illustrating an example coding system 10 that may utilize techniques of the present application, e.g., video coding system 10 (or coding system 10 for short). A video encoder 20 (or encoder 20 for short) and a video decoder 30 (or decoder 30 for short) of video coding system 10 illustrate examples of devices that may be configured to perform techniques according to various examples described in the present application.

[0033] As shown in FIG. 1A, coding system 10 includes a source device 12 configured to provide encoded picture data 21 to, for example, a destination device 14 for decoding the encoded picture data 13.

[0034] The source device 12 includes an encoder 20, and may additionally, i.e. optionally, include a picture source 16, a pre-processor (or pre-processing unit) 18, for example a picture pre-processor 18, and a communication interface or unit 22.

[0035] Picture source 16 may include or be any kind of picture capture device, e.g., a camera for taking pictures of the real world, and / or any kind of picture generation device, e.g., a computer graphics processor for generating computer-animated pictures, or any kind of other device for obtaining and / or providing real-world pictures, computer-generated pictures (e.g., screen content, virtual reality (VR) pictures), and / or any combination thereof (e.g., augmented reality (AR) pictures). Picture source may be any kind of memory or storage for storing any of the above-mentioned pictures.

[0036] In distinction to the pre-processor 18 and the processing performed by the pre-processing unit 18 , the picture or picture data 17 may also be referred to as a raw picture or raw picture data 17 .

[0037] The pre-processor 18 is configured to receive (raw) picture data 17 and perform pre-processing on the picture data 17 to obtain a pre-processed picture 19 or pre-processed picture data 19. The pre-processing performed by the pre-processor 18 may include, for example, cropping, color format conversion (e.g., from RGB to YCbCr), color correction, or noise removal. It may be understood that the pre-processing unit 18 may be an optional component.

[0038] Video encoder 20 is configured to receive pre-processed picture data 19 and to provide encoded picture data 21 (further details are described below, eg, with reference to FIG. 2).

[0039] The communications interface 22 of the source device 12 may be configured to receive the encoded picture data 21 and transmit the encoded picture data 21 (or any further processed version thereof) via the communications channel 13 to another device, e.g., the destination device 14 or any other device, for storage or direct reconstruction.

[0040] The destination device 14 includes a decoder 30 (e.g., a video decoder 30) and may additionally, i.e. optionally, include a communications interface or unit 28, a post-processor 32 (or post-processing unit 32), and a display device 34.

[0041] The communications interface 28 of the destination device 14 is configured to receive the encoded picture data 21 (or any further processed version thereof), e.g., directly from the source device 12 or from any other source, e.g., a storage device, e.g., a storage device for encoded picture data, and to provide the encoded picture data 21 to a decoder 30.

[0042] The communication interface 22 and the communication interface 28 may be configured to transmit or receive the encoded picture data 21 or the encoded data 13 via a direct communication link between the source device 12 and the destination device 14, e.g., a direct wired or wireless connection, or via any type of network, e.g., a wired or wireless network or any combination thereof, or any type of private and public network, or any type of combination thereof.

[0043] The communications interface 22 may be configured to process the encoded picture data 21 using any type of transmission encoding or processing, for example packaging the encoded picture data 21 in a suitable format, for example into packets, and / or for transmission over a communications link or network.

[0044] The communications interface 28 forming the counterpart of the communications interface 22 may for example be configured to receive the transmitted data and process the transmitted data using any type of corresponding transmission decoding or processing and / or unpackaging to obtain the encoded picture data 21.

[0045] Both communication interface 22 and communication interface 28 may be configured as unidirectional communication interfaces, as indicated by the arrows for communication channel 13 in FIG. 1A pointing from source device 12 toward destination device 14, or as bidirectional communication interfaces, and may be configured, for example, to send and receive messages, for example, to set up a connection, confirm and exchange a communication link and / or any other information related to a data transmission, e.g., the transmission of encoded picture data.

[0046] The decoder 30 is configured to receive the encoded picture data 21 and provide decoded picture data 31 or decoded pictures 31 (further details are described below, for example based on Figure 3 or Figure 5).

[0047] Post-processor 32 of destination device 14 is configured to post-process decoded picture data 31 (also referred to as reconstructed picture data), e.g., decoded picture 31, to obtain post-processed picture data 33, e.g., post-processed picture 33. The post-processing performed by post-processing unit 32 may include, e.g., color format conversion (e.g., from YCbCr to RGB), color correction, cropping, or resampling, or any other processing, e.g., to prepare decoded picture data 31 for display by display device 34.

[0048] Display device 34 of destination device 14 is configured to receive post-processed picture data 33, for example, to display the picture to a user or viewer. Display device 34 may be or include any type of display, for example, an integrated or external display or monitor, for showing the reconstructed picture. The display may include, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, liquid crystal on silicon (LCoS), a digital light processor (DLP), or any other type of display.

[0049] 1A illustrates source device 12 and destination device 14 as separate devices, an embodiment of the devices may also include both or both functionality, source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such an embodiment, source device 12 or corresponding functionality and destination device 14 or corresponding functionality may be implemented using the same hardware and / or software or by separate hardware and / or software or any combination thereof.

[0050] As will be clear to a person skilled in the art based on the description, the presence and (exact) division of functions of different units or functions within source device 12 and / or destination device 14 shown in FIG. 1A may vary depending on the actual device and application.

[0051] The encoder 20 (e.g., video encoder 20) or the decoder 30 (e.g., video decoder 30) or both the encoder 20 and the decoder 30 may be implemented by processing circuitry shown in FIG. 1B, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, dedicated to video coding, or any combination thereof. The encoder 20 may be implemented by processing circuitry 46 to embody various modules discussed in connection with the encoder 20 of FIG. 2 and / or any other encoder system or subsystem described herein. The decoder 30 may be implemented by processing circuitry 46 to embody various modules discussed in connection with the decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein. The processing circuitry may be configured to perform various operations discussed later. As shown in FIG. 5, in the case where the techniques are implemented in part in software, the device may store instructions for the software in a suitable non-transitory computer-readable storage medium and may execute instructions in hardware using one or more processors to perform the techniques of this disclosure. Either video encoder 20 and video decoder 30 may be incorporated as part of a combined encoder / decoder (codec) in a single device, for example, as shown in FIG. 1B.

[0052] The source device 12 and the destination device 14 may include any of a wide range of devices, including any type of handheld or fixed device, for example, a notebook or laptop computer, a mobile phone, a smartphone, a tablet or tablet computer, a camera, a desktop computer, a set-top box, a television, a display device, a digital media player, a video game console, a video streaming device (such as a content service server or a content delivery server), a broadcast receiver device, a broadcast transmitter device, and the like, and may use no operating system or any type of operating system. In some cases, the source device 12 and the destination device 14 may be capable of wireless communication. Thus, the source device 12 and the destination device 14 may be wireless communication devices.

[0053] In some cases, the video coding system 10 shown in FIG. 1A is merely an example, and the techniques of this disclosure may be applied to video coding situations (e.g., video encoding or video decoding) that do not necessarily include any data communication between an encoding device and a decoding device. In other examples, data may be retrieved from local memory or streamed over a network, etc. A video encoding device may encode data and store it in memory, and / or a video decoding device may retrieve data from memory and decode it. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but simply encode data in memory and / or retrieve data from memory and decode it.

[0054] For ease of explanation, embodiments of the present invention are described herein by reference to reference software, for example, High-Efficiency Video Coding (HEVC), or Versatile Video coding (VVC), a next-generation video coding standard developed by the ITU-T Video Coding Experts Group (VCEG) and the Joint Collaboration Team on Video Coding (JCT-VC) of the ISO / IEC Motion Picture Experts Group (MPEG). Those skilled in the art will understand that embodiments of the present invention are not limited to HEVC or VVC.

[0055] Encoder and encoding method FIG. 2 shows a schematic block diagram of an exemplary video encoder 20 configured to implement the techniques of the present application. In the example of FIG. 2, the video encoder 20 includes an input 201 (or an input interface 201), 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 loop filter unit 220, a decoded picture buffer (DPB) 230, a mode selection unit 260, an entropy coding unit 270, and an output 272 (or an output interface 272). The mode selection unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a partitioning unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder with a hybrid video codec.

[0056] The residual calculation unit 204, the transform processing unit 206, the quantization unit 208, and the mode selection unit 260 may be considered to form a forward signal path of the encoder 20, while 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, the inter prediction unit 244, and the intra prediction unit 254 may be considered to form a backward signal path of the video encoder 20, which corresponds to the signal path of the decoder (see the video decoder 30 in FIG. 3). The inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244, and the intra prediction unit 254 are also considered to form a “built-in decoder” of the video encoder 20.

[0057] Picture & Picture Division (Picture & Block) The encoder 20 may, for example, be configured to receive via an input 201 a picture 17 (or picture data 17), e.g. a picture of a sequence of pictures forming a video or a video sequence. The received picture or picture data may also be a preprocessed picture 19 (or preprocessed picture data 19). For simplicity, the following description refers to picture 17. Picture 17 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. already coded and / or decoded pictures of the same video sequence, i.e. a video sequence that also includes the current picture).

[0058] A (digital) picture is or can be considered as a two-dimensional array or matrix of samples with intensity values. The samples of the array may also be called pixels (short for picture element) or pels. 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. For color representation, typically three color components are used, i.e. a picture may be represented or include three sample arrays. In an RBG 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 and chrominance format or color space, e.g. YCbCr, including a luminance component denoted by Y (sometimes L is used instead) and two chrominance components denoted by Cb and Cr. The luminance (or luma for short) component Y represents the brightness or intensity of a gray level (e.g., similar to a grayscale picture), while the two chrominance (or chroma for short) components Cb and Cr represent the chromaticity or color information components. Thus, a picture in YCbCr format contains a luminance sample array of luminance sample values ​​(Y) and two chrominance sample arrays of chrominance values ​​(Cb and Cr). A picture in RGB format may be converted or transformed into YCbCr format or vice versa, a process also known as color transformation or conversion. If the picture is monochrome, the picture may contain only a luminance sample array. Thus, a picture may be, for example, an array of luma samples in a monochrome format, or an array of luma samples and two corresponding arrays of chroma samples in 4:2:0, 4:2:2, and 4:4:4 color formats.

[0059] An embodiment of video encoder 20 may include a picture partitioning unit (not shown in FIG. 2) configured to partition picture 17 into multiple (usually non-overlapping) picture blocks 203. These blocks may also be called root blocks, macroblocks (H.264 / AVC), or coding tree blocks (CTBs) or coding tree units (CTUs) (H.265 / HEVC and VVC). The picture partitioning unit may be configured to use the same block size for all pictures of a video sequence and a corresponding grid that defines the block size, or to vary the block size among pictures or a subset or group of pictures, and to partition each picture into corresponding blocks.

[0060] In a further embodiment, the video encoder may be configured to directly receive block 203 of picture 17, e.g., one, some, or all of the blocks that form picture 17. Picture block 203 may also be referred to as a current picture block or a picture block to be coded.

[0061] Similar to the picture 17, the picture block 203 is or can be considered as a two-dimensional array or matrix of samples having intensity values ​​(sample values), although with smaller dimensions than the picture 17. In other words, the block 203 may include, for example, one sample array (e.g., a luma array for a monochrome picture 17, or a luma or chroma array for a color picture), or three sample arrays (e.g., a luma and two chroma arrays for a color picture 17), or any other number and / or type of array, depending on the color format applied. The number of samples in the horizontal and vertical directions (or axes) of the block 203 defines the size of the block 203. Thus, the block may be, for example, an MxN (M columns by N rows) array of samples or an MxN array of transform coefficients.

[0062] The embodiment of video encoder 20 shown in FIG. 2 may be configured to encode picture 17 block-by-block, eg, encoding and prediction are performed for each block 203.

[0063] The embodiment of video encoder 20 shown in FIG. 2 may be further configured to partition and / or encode a picture by using slices (also referred to as video slices), where a picture may be partitioned into or encoded using one or more (generally non-overlapping) slices, each of which may include one or more blocks (e.g., CTUs).

[0064] The embodiment of video encoder 20 shown in FIG. 2 may be further configured to partition and / or encode a picture by using tile groups (also referred to as video tile groups) and / or tiles (also referred to as video tiles), where a picture may be partitioned into or encoded using one or more (generally non-overlapping) tile groups, where each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, where each tile may be, for example, rectangular in shape and may include one or more blocks (e.g., CTUs), e.g., complete or fractional blocks.

[0065] Calculating the residuals The residual calculation unit 204 may be configured to calculate the residual block 205 (also referred to as residual 205) based on the picture block 203 and the prediction block 265 (further details about the prediction block 265 are provided later), for example, by subtracting sample values ​​of the prediction block 265 from sample values ​​of the picture block 203 on a sample-by-sample (pixel-by-pixel) basis to obtain the residual block 205 in the sample domain.

[0066] conversion The transform processing unit 206 may be configured to apply a transform, for example, 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 may represent the residual block 205 in the transform domain.

[0067] The transform processing unit 206 may be configured to apply an integer approximation of a DCT / DST, such as the transform specified for H.265 / HEVC. Compared to an orthogonal DCT transform, such an integer approximation is generally scaled by a certain ratio. In order to maintain the norm of the residual blocks processed by the forward and inverse transforms, an additional scaling factor is applied as part of the transform process. The scaling factor is generally selected based on certain constraints, such as the scaling factor being a power of two for shift operations, the bit depth of the transform coefficients, a trade-off between accuracy and implementation cost, etc. For example, a certain scaling factor may be specified for the inverse transform, e.g., by the inverse transform processing unit 212 (and the corresponding inverse transform, e.g., by the inverse transform processing unit 312 in the video decoder 30), and a corresponding scaling factor for the forward transform, e.g., by the transform processing unit 206 of the encoder 20, may be specified accordingly.

[0068] An embodiment of video encoder 20 (respectively, transform processing unit 206) may be configured to output transform parameters, e.g., a certain transform or transforms, either as is or encoded or compressed by entropy encoding unit 270, such that video decoder 30 may receive the transform parameters and use them for decoding.

[0069] Quantization The quantization unit 208 may be configured to quantize the transform coefficients 207, for example, by applying scalar quantization or vector quantization, to obtain quantized coefficients 209. The quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.

[0070] 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 degree of quantization may be modified by adjusting a quantization parameter (QP). For example, for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. A smaller quantization step size corresponds to a finer quantization, while a larger quantization step size corresponds to a coarser quantization. The applicable quantization step sizes may be indicated by a quantization parameter (QP). The quantization parameter may, for example, be an index into a predefined set of applicable quantization step sizes. For example, a small quantization parameter may correspond to fine quantization (small quantization step size) and a large quantization parameter may correspond to coarse quantization (large quantization step size), or vice versa. Quantization may include division by the quantization step size, and corresponding and / or inverse dequantization by, for example, the inverse quantization unit 210 may include multiplication by the quantization step size. Some standards, for example, HEVC, embodiments may be configured to use the quantization parameter to determine the quantization step size. In general, the quantization step size may be calculated based on the quantization parameter using a fixed point approximation of an equation that includes a division. An additional scaling factor may be introduced for quantization and dequantization to restore the norm of the residual block that may be modified due to the scaling used in the fixed point approximation of the equation for the quantization step size and the quantization parameter. In one example implementation, the scaling of the inverse transform and dequantization may be combined. Alternatively, customized quantization tables may be used, for example, signaled from the encoder to the decoder in the bitstream. Quantization is a lossy operation, and the loss increases as the quantization step size increases.

[0071] Embodiments of video encoder 20 (respectively, quantization unit 208) may be configured to output a quantization parameter (QP), e.g., as is or to be encoded by entropy encoding unit 270, such that video decoder 30 may receive the quantization parameter and apply it for decoding.

[0072] inverse quantization Inverse quantization unit 210 is configured to apply the inverse quantization of quantization unit 208 to the quantized coefficients to obtain dequantized coefficients 211, e.g., by applying the inverse of the quantization scheme applied by quantization unit 208, based on or using the same quantization step size as quantization unit 208. The dequantized coefficients 211, also referred to as dequantized residual coefficients 211, may correspond to transform coefficients 207--although they are generally not identical to the transform coefficients due to losses due to quantization.

[0073] Inverse transformation 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) or other inverse transform, to obtain a reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample domain. The reconstructed residual block 213 may also be referred to as a transform block 213.

[0074] Rebuild The reconstruction unit 214 (e.g., an adder or summator 214) is configured to add the transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265, for example, by adding the sample values ​​of the reconstructed residual block 213 and the sample values ​​of the prediction block 265 --sample by sample-- to obtain a reconstructed block 215 in the sample domain.

[0075] filtering The loop filter unit 220 (or "loop filter" 220 for short) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or in general, to filter the reconstructed samples to obtain filtered samples. The loop filter unit is configured, for example, to smooth pixel transitions or otherwise improve video quality. The loop filter unit 220 may include one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or one or more other filters, for example, a bilateral filter, an adaptive loop filter (ALF), a sharpening, smoothing filter, or a collaborative filter, or any combination thereof. Although the loop filter unit 220 is illustrated in FIG. 2 as being an in-loop filter, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as a filtered reconstructed block 221.

[0076] Embodiments of video encoder 20 (respectively, loop filter unit 220) may be configured to output loop filter parameters (such as sample adaptive offset information), e.g., as is or encoded by entropy encoding unit 270, such that decoder 30 may receive and apply the same loop filter parameters or the respective loop filter for decoding.

[0077] Decoded Picture Buffer The decoded picture buffer (DPB) 230 may be a memory that stores reference pictures or generally reference picture data for encoding video data by the video encoder 20. The DPB 230 may be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221. The decoded picture buffer 230 may be further configured to store other already filtered blocks, e.g., already reconstructed and filtered blocks 221, of the same current picture or different pictures, e.g., already reconstructed pictures, and may provide, e.g., a complete already 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. The decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215 or generally unfiltered reconstructed samples, for example if the reconstructed blocks 215 are not filtered by the loop filter unit 220, or to store any other further processed version of the reconstructed blocks or samples.

[0078] Mode selection (classification & prediction) The mode selection unit 260 includes a partitioning unit 262, an inter prediction unit 244, and an intra prediction unit 254, and is configured to receive or obtain original picture data, e.g., original block 203 (current block 203 of current picture 17), and reconstructed picture data, e.g., filtered and / or unfiltered reconstructed samples or blocks of the same (current) picture and / or from one or more already decoded pictures, e.g., from the decoded picture buffer 230 or other buffers (e.g., line buffers, not shown). The reconstructed picture data is used as reference picture data for prediction, e.g., inter prediction or intra prediction, to obtain a prediction block 265 or predictor 265.

[0079] The mode selection unit 260 may be configured to determine or select a partitioning and prediction mode (e.g., intra or inter prediction mode) for the prediction mode of a current block (which does not include partitioning) and generate a corresponding prediction block 265 used for calculation of the residual block 205 and reconstruction of the reconstructed block 215.

[0080] An embodiment of the mode selection unit 260 may be configured to select a partitioning and prediction mode (e.g., from partitioning and prediction modes supported by or available to the mode selection unit 260) that provides the best match or, in other words, the smallest residual (smallest residual means better compression for transmission or storage) or the smallest signaling overhead (smallest signaling overhead means better compression for transmission or storage), or that considers or balances both. The mode selection unit 260 may be configured to determine the partitioning and prediction mode based on rate-distortion optimization (RDO), i.e., to select the prediction mode that provides the smallest rate-distortion. Terms such as "best," "minimum," "optimum," etc. in this context do not necessarily refer to the overall "best," "minimum," "optimum," etc., but may also refer to the satisfaction of termination or selection criteria such as values ​​exceeding or falling below a threshold, or other constraints that potentially lead to a "suboptimal selection," but that reduce complexity and processing time.

[0081] In other words, the partitioning unit 262 may be configured to partition the block 203 into smaller block partitions or sub-blocks (which also form blocks) using, for example, quadtree partitioning (QT), binary partitioning (BT), or ternary tree partitioning (TT), or any combination thereof in an iterative manner, and to perform, for example, prediction on each of the block partitions or sub-blocks, wherein the mode selection includes selecting a tree structure of the partitioned block 203, and a prediction mode is applied to each of the block partitions or sub-blocks.

[0082] Below, the partitioning (eg, by partitioning unit 260) and prediction processes (by inter prediction unit 244 and intra prediction unit 254) performed by the exemplary video encoder 20 are described in more detail.

[0083] Classification The partitioning unit 262 may partition (or divide) the current block 203 into smaller sections, e.g., smaller blocks of square or rectangular size. These smaller blocks (which may also be called subblocks) may be further partitioned into even smaller sections. This is also called tree partitioning or hierarchical tree partitioning, where, for example, a root block at root tree level 0 (hierarchical level 0, depth 0) may be recursively partitioned, e.g., into two or more blocks at the next lower tree level, e.g., nodes at tree level 1 (hierarchical level 1, depth 1), which may be partitioned again into two or more blocks at the next lower level, e.g., tree level 2 (hierarchical level 2, depth 2), and so on, until, e.g., the partitioning is terminated because a termination criterion is met, e.g., a maximum tree depth or a minimum block size is reached. Blocks that are not further partitioned are also called leaf blocks or leaf nodes of the tree. A tree that uses a partition into two partitions is called a binary tree (BT), a tree that uses a partition into three partitions is called a ternary tree (TT), and a tree that uses a partition into four partitions is called a quad tree (QT).

[0084] As mentioned above, the term "block" used herein may be a portion of a picture, in particular a square or rectangular portion. For example, in the context of HEVC and VVC, a block may be or correspond to a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), and a transform unit (TU), and / or a corresponding block, such as a coding tree block (CTB), a coding block (CB), a transform block (TB), or a prediction block (PB).

[0085] For example, a coding tree unit (CTU) may be or include a CTB of luma samples, two corresponding CTBs of chroma samples of a picture with three sample arrangements, or a CTB of samples of a picture coded using three separate color planes and syntax structures used to code a monochrome picture or sample. Correspondingly, a coding tree block (CTB) may be an NxN block of samples for some value of N such that the division of the components into CTBs is a partition. A coding unit (CU) may be or include a coding block of luma samples, two corresponding coding blocks of chroma samples of a picture with three sample arrangements, or a coding block of samples of a picture coded using three separate color planes and syntax structures used to code a monochrome picture or sample. Correspondingly, a coding block (CB) may be an MxN block of samples for some value of M and N such that the division of the CTB into coding blocks is a partition.

[0086] For example, in an embodiment according to HEVC, a coding tree unit (CTU) may be divided into CUs by using a quadtree structure represented as a coding tree. The decision of whether to code a picture area using inter-picture (temporal) prediction or intra-picture (spatial) prediction is made at the CU level. Each CU may be further divided into one, two, or four PUs according to the PU partition type. Within one PU, the same prediction process is applied, and related information is sent to the decoder based on the PU. After obtaining the residual block by applying the prediction process based on the PU partition type, the CU may be partitioned into transform units (TUs) by another quadtree structure similar to the coding tree for the CU.

[0087] For example, in an embodiment according to the latest video coding standard currently being developed, called versatile video coding (VVC), a combined quad-tree and binary tree (QTBT) partitioning is used, for example, to partition the coding block. In the QTBT block structure, the CU can have either a square or a rectangular shape. For example, the coding tree unit (CTU) is first partitioned by a quad-tree structure. The leaf node of the quad-tree is further partitioned by a binary tree or a ternary (or triple) tree structure. The leaf node of the partitioning tree is called the coding unit (CU), and its segmentation is used for prediction and transformation processing without any further partitioning. This means that the CU, PU, ​​and TU have the same block size in the QTBT coding block structure. In parallel, multi-partition, for example, ternary tree partitioning, may be used together with the QTBT block structure.

[0088] In one example, mode selection unit 260 of video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.

[0089] As mentioned above, video encoder 20 is configured to determine or select a best or optimal prediction mode from a (e.g., predetermined) set of prediction modes. The set of prediction modes may include, for example, intra-prediction modes and / or inter-prediction modes.

[0090] Intra prediction The set of intra prediction modes may include, for example, the 35 different intra prediction modes defined in HEVC, e.g., non-directional modes such as DC (or average) mode and planar mode, or directional modes, or may include, for example, the 67 different intra prediction modes defined for VVC, e.g., non-directional modes such as DC (or average) mode and planar mode, or directional modes.

[0091] The intra prediction unit 254 is configured to generate an intra prediction block 265 using reconstructed samples of neighboring blocks of the same current picture according to an intra prediction mode from a set of intra prediction modes.

[0092] The intra prediction unit 254 (or generally the mode selection unit 260) is further configured to output the intra prediction parameters (or generally information indicating the selected intra prediction mode for the block) to the entropy encoding unit 270 in the form of a syntax element 266 for inclusion in the encoded picture data 21, e.g., so that the video decoder 30 may receive the prediction parameters and use them for decoding.

[0093] Inter Prediction The set (or possible) inter prediction modes depends on the available reference pictures (i.e., e.g., previous at least partially decoded pictures stored in DBP 230) as well as other inter prediction parameters, such as whether the entire reference picture is used to search for the best matching reference block or only a portion of the reference picture, e.g., a search window area around the area of ​​the current block, is used, and / or whether, for example, pixel interpolation, e.g., half / semi-pel and / or quarter-pel interpolation, is applied.

[0094] In addition to the prediction modes mentioned above, skip mode and / or direct mode may be applied.

[0095] The inter prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (both not shown in FIG. 2). The motion estimation unit may be configured to receive or obtain the picture block 203 (current picture block 203 of current picture 17) and the decoded picture 231, or at least one or more already reconstructed blocks, e.g., reconstructed blocks of one or more other / different already decoded pictures 231, for motion estimation. For example, a video sequence may include the current picture and the already decoded picture 231, or in other words, the current picture and the already decoded picture 231 may be part of or form a sequence of pictures that form a video sequence.

[0096] The encoder 20 may be configured to, for example, select a reference block from multiple reference blocks of the same or different pictures among multiple other pictures, and provide the reference picture (or reference picture index) and / or an offset (spatial offset) between the position (x, y coordinates) of the reference block and the position of the current block as an inter-prediction parameter to the motion estimation unit, which offset is also called a motion vector (MV).

[0097] The motion compensation unit is configured to obtain, e.g., receive, inter prediction parameters and perform inter prediction based on or using the inter prediction parameters to obtain inter prediction block 265. The motion compensation performed by the motion compensation unit may include fetching or generating a prediction block based on a motion / block vector determined by motion estimation, possibly performing sub-pixel precision interpolation. Interpolation filtering may generate additional pixel samples from known pixel samples, thus potentially increasing the number of candidate prediction blocks that may be used to code the picture block. Upon receiving a motion vector for the PU of the current picture block, the motion compensation unit may find the prediction block to which the motion vector points in one of the reference picture lists.

[0098] The motion compensation unit may also generate syntax elements associated with the blocks and video slices for use by video decoder 30 in decoding picture blocks of the video slices. In addition to or as an alternative to the slices and their respective syntax elements, tile groups and / or tiles and their respective syntax elements may be generated or used.

[0099] Entropy Coding The entropy encoding unit 270 is configured to apply, for example, an entropy encoding algorithm or scheme (e.g., a variable length coding (VLC) scheme, a context adaptive VLC scheme (CAVLC), an arithmetic coding scheme, binarization, context adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or another entropy encoding method or technique) or bypass (uncompressed) to the quantized coefficients 209, the inter-prediction parameters, the intra-prediction parameters, the loop filter parameters, and / or other syntax elements to obtain encoded picture data 21 that may be output via an output 272, for example in the form of an encoded bitstream 21, such that, for example, the video decoder 30 may receive the parameters and use them for decoding. The encoded bitstream 21 may be transmitted to video decoder 30 or stored in memory for later transmission or retrieval by video decoder 30 .

[0100] Other structural variations of the video encoder 20 may be used to encode the video stream. For example, a non-transform-based encoder 20 may directly quantize the residual signal for a particular block or frame without a transform processing unit 206. In another implementation, the encoder 20 may have the quantization unit 208 and the inverse quantization unit 210 combined into a single unit.

[0101] Decoder and decoding method 3 shows an example of a video decoder 30 configured to implement the techniques of the present application. The video decoder 30 is configured to receive encoded picture data 21 (e.g., encoded bitstream 21), e.g., encoded by encoder 20, to obtain a decoded picture 331. The encoded picture data or bitstream includes information for decoding the encoded picture data, e.g., data representing picture blocks of an encoded video slice (and / or tile group or tile) and associated syntax elements.

[0102] 3, the 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 loop filter 320, a decoded picture buffer (DBP) 330, a mode application unit 360, an inter prediction unit 344, and an intra prediction unit 354. The inter prediction unit 344 may be or include a motion compensation unit. The video decoder 30 may, in some examples, perform a decoding path that is generally the reverse of the encoding path described in connection with the video encoder 100 of FIG. 2.

[0103] As described in relation to encoder 20, inverse quantization unit 210, inverse transform processing unit 212, reconstruction unit 214, loop filter 220, decoded picture buffer (DPB) 230, inter prediction unit 344, and intra prediction unit 354 are also considered to form a "built-in decoder" of video encoder 20. Thus, inverse quantization unit 310 may be functionally identical to inverse quantization unit 110, inverse transform processing unit 312 may be functionally identical to inverse transform processing unit 212, reconstruction unit 314 may be functionally identical to reconstruction unit 214, loop filter 320 may be functionally identical to loop filter 220, and decoded picture buffer 330 may be functionally identical to decoded picture buffer 230. Thus, the descriptions given with respect to the respective units and functions of video encoder 20 apply mutatis mutandis to the respective units and functions of video decoder 30.

[0104] Entropy Decoding The entropy decoding unit 304 is configured to parse the bitstream 21 (or the coded picture data 21 in general) and, e.g., perform entropy decoding on the coded picture data 21 to obtain, e.g., quantized coefficients 309 and / or decoded coding parameters (not shown in FIG. 3), e.g., any or all of inter prediction parameters (e.g., reference picture indexes and motion vectors), intra prediction parameters (e.g., intra prediction modes or indices), transform parameters, quantization parameters, loop filter parameters, and / or other syntax elements. The entropy decoding unit 304 may be configured to apply a decoding algorithm or scheme corresponding to the encoding scheme described in connection with the entropy encoding unit 270 of the encoder 20. The entropy decoding unit 304 may be further configured to provide the inter prediction parameters, intra prediction parameters, and / or other syntax elements to the mode application unit 360 and provide other parameters to other units of the decoder 30. The video decoder 30 may receive syntax elements at the level of a video slice and / or at the level of a video block. In addition to slices and their respective syntax elements, or as an alternative to slices and their respective syntax elements, tile groups and / or tiles and their respective syntax elements may be received and / or used.

[0105] inverse quantization Inverse quantization unit 310 may be configured to receive a quantization parameter (QP) (or information generally related to inverse quantization) and quantized coefficients from encoded picture data 21 (e.g., by parsing and / or decoding, e.g., by entropy decoding unit 304), and apply inverse quantization to the decoded quantized coefficients 309 based on the quantization parameter to obtain dequantized coefficients 311, which may also be referred to as transform coefficients 311. The inverse quantization process may include using the quantization parameter determined by video encoder 20 for each video block in a video slice (or tile or tile group) to determine the degree of quantization and, similarly, the degree of inverse quantization to be applied.

[0106] Inverse transformation The inverse transform processing unit 312 may be configured to receive the dequantized coefficients 311, also referred to as transform coefficients 311, and apply a transform to the dequantized coefficients 311 to obtain a reconstructed residual block 213 in the sample domain. The reconstructed residual block 213 may also be referred to as a transform block 313. The transform may be an inverse transform, e.g., an inverse DCT, an inverse DST, an inverse integer transform, or a conceptually similar inverse transform process. The inverse transform processing unit 312 may further be configured to receive transform parameters or corresponding information from the encoded picture data 21 (e.g., by parsing and / or decoding, e.g., by the entropy decoding unit 304) to determine the transform to apply to the dequantized coefficients 311.

[0107] Rebuild The reconstruction unit 314 (e.g., an adder or summator 314) may be configured to add the reconstructed residual block 313 to the prediction block 365, for example, by adding sample values ​​of the reconstructed residual block 313 and sample values ​​of the prediction block 365 to obtain a reconstructed block 315 in the sample domain.

[0108] filtering A loop filter unit 320 (either in the coding loop or after the coding loop) is configured to filter the reconstructed block 315 to, for example, smooth pixel transitions or otherwise improve video quality to obtain a filtered block 321. The loop filter unit 320 may include one or more loop filters, such as a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, such as a bilateral filter, an adaptive loop filter (ALF), a sharpening, smoothing filter, or a collaborative filter, or any combination thereof. Although the loop filter unit 320 is shown in FIG. 3 as being an in-loop filter, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

[0109] Decoded Picture Buffer The decoded video blocks 321 of the picture are then stored in a decoded picture buffer 330, which stores the decoded picture 331 as a reference picture for subsequent motion compensation with respect to other pictures and / or for output onto a display, respectively.

[0110] The decoder 30 is configured to output the decoded pictures 311 for presentation or viewing to a user, eg, via an output 312.

[0111] prediction The inter prediction unit 344 may be identical to the inter prediction unit 244 (especially the motion compensation unit), and the intra prediction unit 354 may be functionally identical to the inter prediction unit 254, performing the partitioning or partitioning decision and prediction based on partitioning and / or prediction parameters or respective information received from the encoded picture data 21 (e.g., by analyzing and / or decoding, e.g., by the entropy decoding unit 304). The mode application unit 360 may be configured to perform prediction (intra or inter prediction) for each block based on the (filtered or unfiltered) reconstructed picture, block, or respective sample to obtain a prediction block 365.

[0112] When a video slice is coded as an intra-coded (I) slice, the intra prediction unit 354 of the mode application unit 360 is configured to generate a prediction block 365 for a picture block of the current video slice based on the signaled intra prediction mode and data from already decoded blocks of the current picture. When a video picture is coded as an inter-coded (i.e., B or P) slice, the inter prediction unit 344 (e.g., a motion compensation unit) of the mode application unit 360 is configured to generate a prediction block 365 for a video block of the current video slice based on the motion vector and other syntax elements received from the entropy decoding unit 304. For inter prediction, the prediction block may be generated from one of the reference pictures in one of the reference picture lists. The 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 the DPB 330. The same or similar may apply for or by embodiments that use tile groups (e.g., video tile groups) and / or tiles (e.g., video tiles) in addition to or as an alternative to slices (e.g., video slices), e.g., video may be coded using I, P, or B tile groups and / or tiles.

[0113] Mode application unit 360 is configured to determine prediction information for video blocks of a current video slice by parsing motion vectors or related information and other syntax elements, and to generate a predictive block for a current video block being decoded using the prediction information. For example, mode application unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction) used to code the video blocks of the video slice, a slice type for inter prediction (e.g., B slice, P slice, or GPB slice), construction information for one or more of the reference picture lists for the slice, motion vectors for each inter coded video block of the slice, a status of inter prediction for each inter coded video block of the slice, and other information for decoding video blocks in the current video slice. The same or similar may apply for or by embodiments that use tile groups (e.g., video tile groups) and / or tiles (e.g., video tiles) in addition to or as an alternative to slices (e.g., video slices), e.g., video may be coded using I, P, or B tile groups and / or tiles.

[0114] The embodiment of video decoder 30 shown in FIG. 3 may be configured to partition and / or decode pictures by using slices (also referred to as video slices), and a picture may be partitioned into or decoded using one or more (generally non-overlapping) slices, each of which may include one or more blocks (e.g., CTUs).

[0115] The embodiment of video decoder 30 shown in FIG. 3 may be configured to partition and / or decode a picture by using tile groups (also referred to as video tile groups) and / or tiles (also referred to as video tiles), where a picture may be partitioned into or decoded using one or more (generally non-overlapping) tile groups, where each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, where each tile may be, for example, rectangular in shape and may include one or more blocks (e.g., CTUs), e.g., complete or fractional blocks.

[0116] Other variations of the video decoder 30 may be used to decode the encoded picture data 21. For example, the decoder 30 may generate an output video stream without a loop filtering unit 320. For example, a non-transform-based decoder 30 may directly inverse quantize the residual signal for a particular block or frame without the inverse transform processing unit 312. In another implementation, the video decoder 30 may have the inverse quantization unit 310 and the inverse transform processing unit 312 combined into a single unit.

[0117] It should be understood that in the encoder 20 and the decoder 30, the processing result of the current step may be further processed and then output to the next step. For example, after the interpolation filtering, the derivation of the motion vector, or the loop filtering, further operations such as Clip or Shift may be performed on the processing result of the interpolation filtering, the derivation of the motion vector, or the loop filtering.

[0118] It should be noted that further operations may be applied to the derived motion vector of the current block (including but not limited to control point motion vectors in affine mode, lower block motion vectors in affine, planar, ATMVP modes, temporal motion vectors, etc.). For example, the value of the motion vector is constrained to a certain range according to its representation bits. If the representation bits of the motion vector are bitDepth, then the range is -2^(bitDepth-1) to 2^(bitDepth-1)-1, where "^" means exponentiation. For example, if bitDepth is set equal to 16, the range is -32768 to 32767, and if bitDepth is set equal to 18, the range is -131072 to 131071. For example, the values ​​of the derived motion vectors (e.g., the MVs of four 4x4 sub-blocks in one 8x8 block) are constrained such that the maximum difference between the integer parts of the MVs of the four 4x4 sub-blocks is no more than N pixels, such as no more than 1 pixel. Here, we provide two methods for constraining the motion vectors according to bitDepth.

[0119] Method 1: Delete the overflow MSB (Most Significant Bit) by using flowing arithmetic ux = ( mvx+2 bitDepth ) % 2 bitDepth (1) mvx = ( ux >= 2 bitDepth-1 ) ? (ux - 2 bitDepth ) : ux (2) uy = ( mvy+2 bitDepth ) % 2 bitDepth (3) mvy = ( uy >= 2 bitDepth-1 ) ? (uy - 2 bitDepth ) : uy (4) where mvx is the horizontal component of the motion vector of the image block or sub-block, mvy is the vertical component of the motion vector of the image block or sub-block, and ux and uy denote intermediate values.

[0120] For example, if the value of mvx is -32769, after applying equations (1) and (2), the resulting value is 32767. In computer systems, decimal numbers are stored as two's complement. The two's complement of -32769 is 1, 0111, 1111, 1111, 1111 (17 bits), then the MSB is discarded, therefore the resulting two's complement is 0111, 1111, 1111, 1111 (decimal 32767), which is the same as the output by applying equations (1) and (2). ux= ( mvpx + mvdx +2 bitDepth ) % 2 bitDepth (5) mvx = ( ux >= 2 bitDepth-1 ) ? (ux - 2 bitDepth ) : ux (6) uy = ( mvpy + mvdy +2 bitDepth ) % 2 bitDepth (7) mvy = ( uy >= 2 bitDepth-1 ) ? (uy - 2 bitDepth ) : uy (8)

[0121] The operations may be applied during the summation of mvp and mvd as shown in equations (5) to (8).

[0122] Method 2: Remove the overflowing MSB by clipping the value vx = Clip3(-2 bitDepth-1 , 2 bitDepth-1 -1, vx) vy = Clip3(-2 bitDepth-1 , 2 bitDepth-1 -1, vy) In the formula, vx is the horizontal component of the motion vector of the image block or sub-block, vy is the vertical component of the motion vector of the image block or sub-block, x, y, and z correspond to the three input values ​​of the clipping process of MV respectively, and the definition of the function Clip3 is as follows:

number

[0123] 4 is a schematic diagram of a video coding device 400 according to an embodiment of the present disclosure. The video coding device 400 is suitable for implementing the disclosed embodiments as described herein. In an embodiment, the video coding device 400 may be a decoder, such as the video decoder 30 of FIG. 1A, or an encoder, such as the video encoder 20 of FIG. 1A.

[0124] Video coding device 400 includes an incoming port 410 (or input port 410) and a receiver unit (Rx) 420 for receiving data, a processor, logic unit, or central processing unit (CPU) 430 for processing data, a transmitter unit (Tx) 440 and an outgoing port 450 (or output port 450) for transmitting data, and a memory 460 for storing data. Video coding device 400 may also include optical-electrical (OE) and electrical-optical (EO) components coupled to the incoming port 410, the receiver unit 420, the transmitter unit 440, and the outgoing port 450 for emitting or receiving optical or electrical signals.

[0125] The processor 430 is implemented by hardware and software. The processor 430 may be implemented as one or more CPU chips, cores (e.g., as a multi-core processor), FPGA, ASIC, and DSP. The processor 430 communicates with the incoming port 410, the receiver unit 420, the transmitter unit 440, the outgoing port 450, and the memory 460. The processor 430 includes a coding module 470. The coding module 470 implements the above-disclosed embodiments. For example, the coding module 470 implements, processes, prepares, or provides various coding operations. Thus, the inclusion of the coding module 470 significantly improves the functionality of the video coding device 400 and provides transitions of the video coding device 400 to different states. Alternatively, the coding module 470 is implemented as instructions stored in the memory 460 and executed by the processor 430.

[0126] Memory 460 may include one or more disks, tape drives, and solid state drives, and may be used as an over-flow data storage device for storing programs when such programs are selected for execution, as well as for storing instructions and data read during execution of the programs. Memory 460 may be, for example, 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).

[0127] FIG. 5 is a simplified block diagram of an apparatus 500 that may be used as either or both of source device 12 and destination device 14 of FIG. 1, according to an exemplary embodiment.

[0128] The processor 502 of the apparatus 500 may be a central processing unit. Alternatively, the processor 502 may be any other type of device or devices, existing or later developed, capable of manipulating or processing information. Although the disclosed implementations may be performed by a single processor as shown, e.g., processor 502, advantages in speed and efficiency may be realized by using two or more processors.

[0129] The memory 504 of the apparatus 500 can be a read-only memory (ROM) device or a random access memory (RAM) device in implementation. Any other suitable type of storage device can be used as the memory 504. The memory 504 can include code and data 506 that is accessed by the processor 502 using a bus 512. The memory 504 can further include an operating system 508 and application programs 510, which include at least one program that enables the processor 502 to perform the methods described herein. For example, the application programs 510 can include applications 1 through N, which further include a video coding application that performs the methods described herein.

[0130] The apparatus 500 may also include one or more output devices, such as a display 518. The display 518, in one example, may be a touch-sensitive display that combines a display with touch-sensing elements operable to sense touch input. The display 518 may be coupled to the processor 502 via the bus 512.

[0131] Although shown here as a single bus, bus 512 of device 500 may be comprised of multiple buses. Additionally, secondary storage 514 may be directly coupled to the other components of device 500 or may be accessed over a network, and may include a single integrated unit such as a memory card or multiple units such as multiple memory cards. Thus, device 500 may be implemented in a wide variety of configurations.

[0132] Details of the Intra-Subpartition (ISP) tool can be found in JVET-M0102, and a brief description of the tool is given below.

[0133] The ISP tool divides the luma intra-predicted block into two or four subpartitions vertically or horizontally depending on the block size, as shown in Table 1. Figures 6 and 7 show examples of two possibilities. All subpartitions satisfy the condition that they have at least 16 samples.

[0134] [Table 1]

[0135] For each of these subpartitions, a residual signal is generated by entropy decoding the coefficients sent by the encoder, then dequantizing and inverse transforming them. The subpartitions are then intra predicted, and finally the corresponding reconstructed samples are obtained by adding the residual signal to the prediction signal. Thus, the reconstructed values ​​of each subpartition are available to generate the prediction of the next subpartition, which repeats the process, and so on. All subpartitions share the same intra mode.

[0136] Based on the intra mode and the partitioning used, two different classes of processing orders are used, called normal order and reverse order. In normal order, the first sub-partition to be processed is the sub-partition that includes the top-left sample of the CU, and then continues downward (horizontal partitioning) or to the right (vertical partitioning). As a result, the reference samples used to generate the prediction signal of the sub-partition are only on the left and upper side of the line. On the other hand, the reverse processing order either starts with the sub-partition that includes the bottom-left sample of the CU and continues upward, or starts with the sub-partition that includes the top-right sample of the CU and continues to the left.

[0137] 8 shows the position of the line of reference samples used for intra prediction of a block. Depending on the index of the reference line, the samples of the predicted block (block unit) may be predicted using reference samples that are not adjacent to the predicted block, i.e., when the index of the reference line is not equal to 0.

[0138] The planar intra prediction modes are specified in the VVC draft as follows:

[0139] The inputs to this process are: - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - Neighboring samples p[x][y] with x = -1, y = -1..nTbH and x = 0..nTbW, y = -1 It is.

[0140] The output of this process is the predicted samples predSamples[x][y], x = 0..nTbW - 1, y = 0..nTbH - 1.

[0141] The variables nW and nH are derived as follows: nW = Max( nTbW, 2 ) nH = Max( nTbH, 2 )

[0142] The values ​​of the predicted samples predSamples[ x ][ y ], where x = 0..nTbW - 1 and y = 0..nTbH - 1, are derived as follows: predV[ x ][ y ] = ( ( nH - 1 - y ) * p[ x ][ -1 ] + ( y + 1 ) * p[ -1 ][ nTbH ] ) << Log2 ( nW ) predH[ x ][ y ] = ( ( nW - 1 - x ) * p[ -1 ][ y ] + ( x + 1 ) * p[ nTbW ][ -1 ] ) << Log2 ( nH ) predSamples[ x ][ y ] = ( predV[ x ][ y ] + predH[ x ][ y ] + nW * nH ) >> (Log2 ( nW ) + Log2 ( nH ) + 1 )

[0143] The DC intra prediction process is specified in the VVC draft as follows:

[0144] The inputs to this process are: - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - Neighboring samples p[x][y] with x = -1, y = -1..nTbH - 1 and x = 0..nTbW - 1, y = -1 It is.

[0145] The output of this process is the predicted samples predSamples[x][y], x = 0..nTbW - 1, y = 0..nTbH - 1.

[0146] The values ​​of the predicted samples predSamples[ x ][ y ], x = 0..nTbW − 1, y = 0..nTbH − 1, are derived by the following ordered steps: 1. The variable dcVal is derived as follows: - When nTbW is equal to nTbH,

number

number

number

[0147] 2. The predicted samples predSamples[x][y] are derived as follows: predSamples[ x ][ y ] = dcVal for x = 0.. nTbW - 1, y = 0.. nTbH - 1

[0148] State-of-the-art methods only use directional intra prediction when the reference line index is non-zero, i.e., in this case, the DC and PLANAR intra prediction modes are disabled.

[0149] Another case in which the DC intra prediction mode is not implemented is when intra sub-partitioning (ISP) is used.

[0150] Versions of the VVC draft specify different coding of intra prediction modes. The choice of the sequence of syntax elements signaled in the bitstream depends on whether a particular tool is enabled or disabled. In particular, the mpm flag is signaled only when the "intra_luma_ref_idx" and "intra_subpartitions_mode_flag" flags are equal to 0 (see Table 2).

[0151] [Table 2]

[0152] Currently, several versions of MPM lists are kept in the software and specification draft of VVC. The design of hardware using several MPM lists is still undesirable. However, if intra-prediction modes are enabled when they are currently disabled, it will result in two combinations of intra flags that generate similar intra-predicted blocks. Obviously, this design is redundant, and either the signaling part or the intra-prediction part should be modified to solve this problem.

[0153] The scope of the embodiment lies in the modification of the PLANAR and DC intra prediction processes for cases where the reference sample is not adjacent to the block being predicted or the predicted block is further divided (e.g., using ISP). The modification includes not only the process of determining the prediction sample, but also the filtering and PDPC of the reference sample.

[0154] The aim of such a modification lies in the possibility of having a unified intra-mode signaling mechanism for all intra-prediction tools.

[0155] The embodiment proposes to modify the processing of reference samples and introduce a conditional switching of PDPC when DC or PLANAR intra prediction modes are used and the reference samples are not adjacent to the block being predicted or the predicted block is further divided (i.e., in the ISP case). The processing involves the selection of reference samples from the reconstructed samples in the top and left areas (shown in Fig. 8) and filtering of those reference samples.

[0156] The embodiment aims to provide the possibility of having a single unified signaling mechanism for coding intra-prediction modes. An exemplary unified signaling method for coding intra-prediction modes is given in Table 3.

[0157] [Table 3]

[0158] The difference between the coding methods shown in Table 2 and Table 3 is that the conditional signaling of intra_luma_mpm_flag is removed in the proposed example syntax.

[0159] It can be noticed from the specification that the PLANAR intra prediction mode cannot work when the index of the reference line is non-zero. The embodiment of the present invention shown in FIG. 9 discloses how this can be handled. In this figure, the case where the third reference line is used. The reference samples selected for the PLANAR intra prediction mode are represented by squares filled with diagonal lines. Assuming that the position of the first top-left sample (denoted as "A") is equal to (0, 0), the PLANAR intra prediction can be modified as follows:

[0160] The inputs to this process are: - Variable refIdx that specifies the index of the reference line for intra prediction - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - Reference samples p[x][y] where x = -1-refIdx, y = -refIdx..nTbH and x = -refIdx..nTbW, y = -1-refIdx It is.

[0161] The output of this process is the predicted samples predSamples[x][y], x = 0..nTbW - 1, y = 0..nTbH - 1.

[0162] The variables nW and nH are derived as follows: nW = Max( nTbW, 2 ) nH = Max( nTbH, 2 )

[0163] The values ​​of the predicted samples predSamples[ x ][ y ], where x = 0..nTbW - 1 and y = 0..nTbH - 1, are derived as follows: predV[ x ][ y ] = ( ( nH - 1 - y ) * p[ x ][ -1 - refIdx ] + ( y + 1 ) * p[ -1 - refIdx ][ nTbH ] ) << Log2 ( nW ) predH[ x ][ y ] = ( ( nW - 1 - x ) * p[ -1 - refIdx ][ y ] + ( x + 1 ) * p[ nTbW ][ -1 - refIdx ] ) << Log2 ( nH ) predSamples[ x ][ y ] = ( predV[ x ][ y ] + predH[ x ][ y ] + nW * nH ) >> ( Log2 ( nW ) + Log2 ( nH ) + 1 )

[0164] An alternative embodiment shown in Figure 10 discloses another method of selecting a reference sample from a reference line for the PLANAR intra prediction mode, which may be described as follows.

[0165] The inputs to this process are: - Variable refIdx that specifies the index of the reference line for intra prediction - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - Neighboring samples p[x][y] where x = -1-refIdx, y = -1-refIdx..nTbH-refIdx and x = -refIdx..nTbW-refIdx, y = -1-refIdx It is.

[0166] The output of this process is the predicted samples predSamples[x][y], x = 0..nTbW - 1, y = 0..nTbH - 1.

[0167] The variables nW and nH are derived as follows: nW = Max( nTbW, 2 ) nH = Max( nTbH, 2 )

[0168] The values ​​of the predicted samples predSamples[ x ][ y ], where x = 0..nTbW - 1 and y = 0..nTbH - 1, are derived as follows: predV[ x ][ y ] = ( ( nH - 1 - y ) * p[ x-refIdx ][ -1-refIdx ] + ( y + 1 ) * p[ -1-refIdx ][ nTbH-refIdx ] ) << Log2 ( nW ) predH[ x ][ y ] = ( ( nW - 1 - x ) * p[ -1-refIdx ][ y-refIdx ] + ( x + 1 ) * p[ nTbW-refIdx ][ -1-refIdx ] ) << Log2 ( nH ) predSamples[ x ][ y ] = ( predV[ x ][ y ] + predH[ x ][ y ] + nW * nH ) >> ( Log2 ( nW ) + Log2 ( nH ) + 1 )

[0169] Another alternative embodiment consists in applying a special displacement for two samples whose values ​​are used in bi-prediction as bottom-line sample value and right-side sample value, respectively. It can be noticed that in Fig. 11 the reference samples are selected from gapped reference lines. The specification text for this embodiment can be as follows:

[0170] The inputs to this process are: - Variable refIdx that specifies the index of the reference line for intra prediction - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - Neighboring samples p[x][y] where x = -1-refIdx, y = -1-refIdx..nTbH-refIdx and x = -refIdx..nTbW-refIdx, y = -1-refIdx It is.

[0171] The output of this process is the predicted samples predSamples[x][y], x = 0..nTbW - 1, y = 0..nTbH - 1.

[0172] The variables nW and nH are derived as follows: nW = Max( nTbW, 2 ) nH = Max( nTbH, 2 )

[0173] The values ​​of the predicted samples predSamples[ x ][ y ], where x = 0..nTbW - 1 and y = 0..nTbH - 1, are derived as follows: predV[ x ][ y ] = ( ( nH - 1 - y ) * p[ x-refIdx ][ -1-refIdx ] + ( y + 1 ) * p[ -1-refIdx ][ nTbH] ) << Log2 ( nW ) predH[ x ][ y ] = ( ( nW - 1 - x ) * p[ -1-refIdx ][ y-refIdx ] + ( x + 1 ) * p[ nTbW ][ -1-refIdx ] ) << Log2 ( nH ) predSamples[ x ][ y ] = ( predV[ x ][ y ] + predH[ x ][ y ] + nW * nH ) >> (Log2 (nW) + Log2 (nH) + 1)

[0174] The DC intra prediction process may also not be invoked when the reference line index is non-zero.

[0175] The embodiment shown in Figures 12 and 13 discloses how to perform intra prediction using DC mode when the reference line index is non-zero. The sampling mechanism in this case is similar to the sampling mechanism disclosed above for the PLANAR intra prediction mode.

[0176] The inputs to this process are: - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - Variable refIdx that specifies the index of the reference line for intra prediction - Neighboring samples p[x][y] where x = -1-refIdx, y = -1-refIdx..nTbH-refIdx-1 and x = -refIdx..nTbW-refIdx-1, y = -1-refIdx It is.

[0177] The output of this process is the predicted samples predSamples[x][y], x = 0..nTbW - 1, y = 0..nTbH - 1.

[0178] The values ​​of the predicted samples predSamples[ x ][ y ], x = 0..nTbW − 1, y = 0..nTbH − 1, are derived by the following ordered steps:

[0179] 3. The variable dcVal is derived as follows: - When nTbW is equal to nTbH,

number

number

number

[0180] 4. The predicted samples predSamples[ x ][ y ] are derived as follows: predSamples[ x ][ y ] = dcVal for x = 0.. nTbW - 1, y = 0.. nTbH - 1

[0181] Another inventive embodiment disables intra reference sample smoothing when the reference sample is not adjacent to the block being predicted, i.e. when the index of the reference line of the reference sample (signaled by "intra_luma_ref_idx") is not equal to 0. Another embodiment consists in varying the reference sample filter for the PLANAR intra prediction mode relative to the index of the reference line of the reference sample.

[0182] Exemplary filter selections are provided in Tables 4 and 5.

[0183] [Table 4]

[0184] [Table 5]

[0185] Another embodiment of the present invention allows PLANAR and DC intra prediction modes to be used for intra prediction of a sub-partition when the Intra Sub-Partition (ISP) flag is set to 1. It is proposed not to perform PDPC operations when the ISP flag is set to 1.

[0186] For the case where ISP mode is on, an example embodiment of how to process DC Intra is as follows. - Calculate the DC value with respect to the reference sample of the entire block, - Use the predicted DC value as the intra predictor for all sub-blocks that belong to the block being predicted.

[0187] A method and apparatus are provided for unified reference sample and interpolation filter selection in intra prediction using sub-partition and multi-reference line intra prediction. The combination of several intra prediction mechanisms in a single intra prediction module (254, 354 in Fig. 2 and Fig. 3) requires unification of their processing steps. In particular, it is desired that the following points are the same or have a minimum number of checks: - Signaling the index of the intra prediction mode - Preparation of a set of reference samples from reconstructed neighboring samples - Reference sample filtering - Sub-pixel Interpolation Filtering

[0188] Although the derivation of the intra-prediction mode based on the intra-prediction mode index is not as critical as the signaling of the intra-prediction mode, it is still an important point since its derivation is part of the intra-prediction pipeline that can introduce additional delay, especially when the block size is small. The reason for this delay is that intra-prediction may start only after the intra-prediction mode is derived, and the process of intra-prediction is faster for smaller sized blocks.

[0189] Embodiments of the present invention aim at unifying the intra smoothing decision-making steps for different intra prediction mechanisms, including: - Intrasubdivision (ISP) - Mode-dependent intra smoothing (MDIS) - Wide-angle intra prediction (WAIP) - Multi-reference line prediction (MRLP) - Position-dependent intra prediction combination (PDPC)

[0190] An embodiment of the present invention is a decision-making process that performs the selection of reference and interpolation filters based on examining a set of conditions including: - Block aspect ratio - Length of the main reference side - Intra prediction mode - Intra subdivision -

[0191] The steps of the embodiment are as follows: - Perform a quick check if intra smoothing is required based on the flag parsed from the bitstream and the filtering state of the block has been detected, the state includes: No smoothing 〇Smoothing o Orientation-dependent smoothing (size-dependent smoothing may be considered as a kind of orientation-dependent smoothing) When a state is detected as directionally dependent, the intra prediction mode and the number of samples in the block to be predicted are used to determine the intra smoothing method to be applied, which may include one or a combination of the following methods: Adjustment of the strength of filtering of reference samples Adjusting the strength of the interpolation filtering, e.g. fG or fC ○ Existence of PDPC stage When a no smoothing condition is detected, define the combination of intra smoothing methods to not include any of the intra smoothing methods. - Specifies the default combination of intra smoothing methods based on the number of samples in the block being predicted when a smooth condition is detected. - Perform intra prediction involving a selected combination of intra smoothing methods.

[0192] A draft portion of the VVC specification that implements state derivation according to the steps listed above may be as follows:

[0193] The inputs to this process are: - Intra prediction mode predModeIntra - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - variable nCbW specifying the width of the coding block - variable nCbH that specifies the height of the coding block - Color component index cIdx It is.

[0194] The output of this process is the modified intra prediction mode predModeIntra, the intraPredAngle parameter RefFilterFlag and the InterpolationFlag variable.

[0195] The variables nW and nH are derived as follows: - If IntraSubPartitionsSplitType is equal to ISP_NO_SPLIT or cIdx is not equal to 0, the following applies: nW = nTbW (8-125) nH = nTbH (8-126) - Otherwise (IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT and cIdx is equal to 0), the following applies: nW = nCbW nH = nCbH

[0196] The variable whRatio is set equal to Abs(Log2(nW / nH)).

[0197] For non-square blocks (nW not equal to nH), the intra prediction mode predModeIntra is modified as follows: - If all of the following conditions are true, predModeIntra is set equal to (predModeIntra + 65): - nW is greater than nH - predModeIntra is 2 or greater. - predModeIntra is ( whRatio > 1 ) ? ( 8 + 2 * whRatio ) : less than 8 - Otherwise, if all of the following conditions are true, then predModeIntra is set equal to (predModeIntra - 67): - nH is greater than nW - predModeIntra is less than or equal to 66 - predModeIntra is ( whRatio > 1 ) ? ( 60 - 2 * whRatio ) : greater than 60

[0198] The angle parameter intraPredAngle is determined as specified in Table 8-5 using the value of predModeIntra.

[0199] [Table 6]

[0200] The variable filterFlag is derived as follows: - The variable nTbS is set equal to log2(nW) + log2(nH). If one or more of the following conditions are true, filterFlag is set equal to 0: - cIdx is not equal to 0 - refIdx is not equal to 0 - IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT, cIdx is equal to 0, predModeIntra is greater than or equal to INTRA_ANGULAR34, and nW is greater than 8. - IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT, cIdx is equal to 0, predModeIntra is less than INTRA_ANGULAR34, and nH is greater than 8. - Otherwise, if predModeIntra is INTRA_PLANAR, then the variable filterFlag is set equal to nTbS > 5 ? 1 : 0. Otherwise, if intraPredAngle is greater than 32, the variable filterFlag is set equal to 1. - Otherwise the following applies: - The variable minDistVerHor is set equal to Min(Abs(predModeIntra - 50), Abs(predModeIntra - 18)). - The variable intraHorVerDistThres[nTbS] is defined in Table 8-4. The variable filterFlag is derived as follows: - If minDistVerHor is greater than intraHorVerDistThres[nTbS] or Abs(intraPredAngle)>32, then filterFlag is set equal to 1.

[0201] [Table 7]

[0202] The output variables RefFilterFlag and InterpolationFlag are derived as follows: If predModeIntra is INTRA_PLANAR or predIntraAng is an integer multiple of 32, then the variable RefFilterFlag is set equal to filterFlag and InterpolationFlag is set equal to 0. - Otherwise, the variable RefFilterFlag is set equal to 0 and InterpolationFlag is set equal to filterFlag.

[0203] In the above description, two flags are derived: RefFilterFlag and InterpolationFlag. When RefFilterFlag is 1, the reference samples are filtered before being used for intra prediction. For example, a filter with coefficients φ(x,y) / 4 may be applied.

[0204] InterpolationFlag controls the selection of the interpolation filter. In the sub-sample interpolation step of the directional intra prediction process, when InterpolationFlag is 1, the fG coefficients are used, otherwise the fC coefficients are used (see Table 8-6).

[0205] [Table 8]

[0206] An alternative embodiment may be assembled as follows.

[0207] The inputs to this process are: - Intra prediction mode predModeIntra - Variable nTbW that specifies the width of the transformation block - Variable nTbH that specifies the height of the transformation block - variable nCbW specifying the width of the coding block - variable nCbH that specifies the height of the coding block - Color component index cIdx It is.

[0208] The output of this process is the modified intra prediction mode predModeIntra, the intraPredAngle parameter RefFilterFlag and the InterpolationFlag variable.

[0209] The variables nW and nH are derived as follows: - If IntraSubPartitionsSplitType is equal to ISP_NO_SPLIT or cIdx is not equal to 0, the following applies: nW = nTbW nH = nTbH - Otherwise (IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT and cIdx is equal to 0), the following applies: nW = nCbW nH = nCbH

[0210] The variable whRatio is set equal to Abs(Log2(nW / nH)).

[0211] For non-square blocks (nW not equal to nH), the intra prediction mode predModeIntra is modified as follows: - predModeIntraOrig is set equal to predModeIntra. - If all of the following conditions are true, predModeIntra is set equal to (predModeIntra + 65): - nW is greater than nH - predModeIntra is 2 or greater. - predModeIntra is ( whRatio > 1 ) ? ( 8 + 2 * whRatio ) : less than 8 - Otherwise, if all of the following conditions are true, then predModeIntra is set equal to (predModeIntra - 67): - nH is greater than nW - predModeIntra is less than or equal to 66 - predModeIntra is ( whRatio > 1 ) ? ( 60 - 2 * whRatio ) : greater than 60

[0212] The angle parameter intraPredAngle is determined as specified in Table 8-5 using the value of predModeIntra. - The variable nTbS is set equal to log2(nW) + log2(nH). The variable smoothState is set to 0 (FILTER_NONE) when one of the following conditions is true: - The variable nTbS is less than or equal to 2. - cIdx is not equal to 0 - refIdx is not equal to 0 - predModeIntraOrig is INTRA_DC - ISP flag is on When intraPredAngle is greater than 32, the variable smoothState is set to 1 (FILTER_ALWAYS). - Otherwise, smoothState is set to 2 (FILTER_MDIS). - If smoothState is less than 2, then filterFlag is set equal to smoothState. - Otherwise, filterFlag is set equal to 1 if one of the following conditions is true: - predModeIntraOrig is INTRA_PLANAR and nTbS is greater than 5 - predModeIntraOrig is greater than 1, predModeIntraOrig is less than 67, and Min( Abs( predModeIntra - 50 ), Abs( predModeIntra - 18 ) ) is greater than intraHorVerDistThres[ nTbS ].

[0213] The output variables RefFilterFlag and InterpolationFlag are derived as follows: If predModeIntra is INTRA_PLANAR or predIntraAng is an integer multiple of 32, then the variable RefFilterFlag is set equal to filterFlag and InterpolationFlag is set equal to 0. - Otherwise, the variable RefFilterFlag is set equal to 0 and InterpolationFlag is set equal to filterFlag.

[0214] Further optimization of MDIS decision making is possible when the following modification of smoothState is set to parts of 2 (FILTER_MDIS). ... If smoothState is less than 2, then filterFlag is set equal to smoothState. - Otherwise, filterFlag is set equal to 1 if one of the following conditions is true: - predModeIntraOrig is INTRA_PLANAR and nTbS is greater than 5 - predModeIntraOrig is greater than 1, predModeIntraOrig is less than 67, and Abs( IntraPredAngle ) is greater than or equal to IntraPredAngleThr [nTbS]. -

[0215] [Table 9]

[0216] The output variables RefFilterFlag and InterpolationFlag are derived as follows: If predModeIntra is INTRA_PLANAR or predIntraAng is an integer multiple of 32, then the variable RefFilterFlag is set equal to filterFlag and InterpolationFlag is set equal to 0. - Otherwise, the variable RefFilterFlag is set equal to 0 and InterpolationFlag is set equal to filterFlag. ...

[0217] Based on the above embodiment, the set of conditions for the no smoothing state may include one or more of the following: - ISP flag is on - refIdx is greater than 1 - The length of the main reference side is smaller than the main side reference threshold.

[0218] The major aspect reference threshold may be a predefined constant value equal to either 4, 8, or 16.

[0219] Additionally, when the ISP flag is on, different thresholds may be applied to determine the value of filterFlag. Tables 6 and 7 illustrate this dependency of threshold variations on the value of the predIntraAng parameter and on the value of intraPredMode.

[0220] [Table 10]

[0221] [Table 11]

[0222] FIG. 14 is a block diagram illustrating an example of selection of an interpolation filter type. As shown in step 1 of FIG. 14, if ISP is on (i.e., IntraSubPartitionsSplitType!=ISP_NO_SPLIT), a one-step / 1 check decision of the interpolation filter type for ISP may be performed. When ISP is on, there is no mode dependency. When ISP is on, the value of filterFlag is 0, and the interpolation filter type fC is selected. This may lead to unification of decision-making steps.

[0223] When the ISP is off (i.e., no ISP), the normal case is performed as shown in step 2 and step 3. The normal case is mode dependent. In step 2, an intra-prediction mode is derived. In step 3, a mode- and size-dependent condition for the type of the interpolation filter is derived. Thus, there are at least three steps of determination of the type of the interpolation filter for the normal case. After step 3, the type of the interpolation filter is selected based on the mode- and size-dependent condition derived in step 3.

[0224] 15 is a block diagram showing another example of selection of an interpolation filter type comparable to the normal case. In the normal case, intra mode is derived when MRL is off (i.e., refIdx==0) and ISP is on (i.e., IntraSubPartitionsSplitType!=ISP_NO_SPLIT). For example, most probable mode (MPM) and non-MPM lists are constructed during intra mode derivation.

[0225] Then, a type of mode-dependent interpolation filter is selected. MDIS-based smoothing of reference samples or selection of an interpolation filter is performed during the selection of the mode-dependent interpolation filter. A minimum number of reference samples are fetched from the nearest reference row and column. An intra predictor is generated after fetching the reference samples. For example, sequential prediction of up to four subblocks may be performed during the generation of the predictor.

[0226] Compared to the normal case, embodiments of the present invention remove the mode dependency when selecting the type of interpolation filter when MRL is off (i.e., refIdx==0) and ISP is on (i.e., IntraSubPartitionsSplitType!=ISP_NO_SPLIT). The intra mode can be derived in parallel with the filter selection. Hence, a shorter critical path when embodiments of the present invention are used when generating intra predictions.

[0227] Typically, generating a prediction for an ISP is more complicated as it requires an iterative decoding process. Embodiments of the present invention can increase the efficiency of the decoding.

[0228] In particular, the following methods and embodiments of predictive coding of a current block are implemented by a decoding or encoding device. The decoding device may be the video decoder 30 of FIG. 1A or the decoder 30 of FIG. 3. The encoding device may be the video encoder 20 of FIG. 1A or the encoder 20 of FIG. 2.

[0229] According to embodiment 1600 (see FIG. 16 ), a device obtains intra-subpartition (ISP) information in step 1601, and the ISP information indicates whether the ISP is used to split the current block. The ISP information may be indicated by IntraSubPartitionsSplitType. When IntraSubPartitionsSplitType != ISP_NO_SPLIT, the ISP is used to split the current block (i.e., the ISP is on).

[0230] In step 1602, the device selects a set of coefficients of an interpolation filter based on information of the ISP, and the set of coefficients of the interpolation filter is fG coefficients or fC coefficients. A value of a filter flag (filterFlag) may be used to indicate that the set of coefficients of the interpolation filter is fG coefficients or fC coefficients. When the value of filterFlag is 0, the fC coefficients are selected. Otherwise, the fG coefficients are selected.

[0231] When the information of ISP indicates that ISP is used to split the current block, the filtering state of the block is the non-smoothed state. The filtering state of the block may be determined by a flag smoothState, and the filtering state of the block is the non-smoothed state when the value of smoothState is 0. The value of filterFlag is equal to the value of smoothState, which means that when the filtering state of the block is the non-smoothed state, the value of filterFlag is 0. The fC coefficient is selected accordingly.

[0232] In step 1603, the device obtains a predicted sample of the current block by applying the set of coefficients to the reference sample. The device may determine an interpolation filter coefficient from the set of coefficients of an interpolation filter based on an intra-prediction mode of the current block, and then obtain the predicted sample of the current block by applying the determined interpolation filter coefficient to the reference sample.

[0233] According to embodiment 1700 (see FIG. 17), the device detects the state of filtering of the block based on the information of the ISP in step 1701, where the state of filtering of the block includes a no-smooth state, a smooth state, or a direction-dependent smooth state. The information of the ISP may be indicated by IntraSubPartitionsSplitType. When IntraSubPartitionsSplitType != ISP_NO_SPLIT, the ISP is used to split the current block (i.e., the ISP is on). When the information of the ISP indicates that the ISP is used to split the current block, the state of filtering of the block is a no-smooth state. The state of filtering of the block may be determined by a flag smoothState, where the state of filtering of the block is a no-smooth state when the value of smoothState is 0.

[0234] In step 1702, the device selects a set of coefficients of an interpolation filter based on a value of a filtering state of the block, and the set of coefficients of the interpolation filter is fG coefficients or fC coefficients. A value of a filter flag (filterFlag) may be used to indicate that the set of coefficients of the interpolation filter is fG coefficients or fC coefficients. When the value of filterFlag is 0, the fC coefficients are selected. Otherwise, the fG coefficients are selected.

[0235] The value of filterFlag is equal to the value of smoothState, which means that when the filtering state of the block is in the no smooth state, the value of filterFlag is 0. The fC coefficient is selected accordingly.

[0236] In step 1703, the device obtains a predicted sample of the current block by applying the set of coefficients to the reference sample. The device may determine interpolation filter coefficients from the set of coefficients of the interpolation filter based on the intra-prediction mode of the current block, and then obtain the predicted sample of the current block by applying the determined interpolation filter coefficients to the reference sample.

[0237] Detailed information about the embodiment 1600 or 1700 is provided in the above embodiments.

[0238] Figure 18 shows an embodiment of a device 1800. The device 1800 may be the video decoder 30 of Figure 1A or the decoder 30 of Figure 3, or the video encoder 20 of Figure 1A or the encoder 20 of Figure 2. The device 1800 may be used to implement the embodiment 1600 and other embodiments described above.

[0239] The device 1800 for intra prediction of a picture includes an acquisition unit 1801, a selection unit 1802, and a prediction unit 1803. The acquisition unit 1801 is configured to acquire intra-subdivision (ISP) information, where the information of the ISP indicates whether the ISP is used to split a current block. The selection unit 1802 is configured to select a set of coefficients of an interpolation filter based on the information of the ISP, where the set of coefficients of the interpolation filter are fG coefficients or fC coefficients. The prediction unit 1803 is configured to acquire a predicted sample of the current block by applying the set of coefficients to a reference sample.

[0240] A selection unit 1802 configured to determine a filtering state of the block to be a no-smoothing state when the ISP information indicates that an ISP is used to split the current block, and to select an fC coefficient when the filtering state of the block is a no-smoothing state.

[0241] a prediction unit 1803 configured to determine interpolation filter coefficients from a set of coefficients of an interpolation filter based on an intra-prediction mode of the current block, and obtain a predicted sample of the current block by applying the determined interpolation filter coefficients to a reference sample.

[0242] Figure 19 shows an embodiment of a device 1900. The device 1900 may be the video decoder 30 of Figure 1A or the decoder 30 of Figure 3, or the video encoder 20 of Figure 1A or the encoder 20 of Figure 2. The device 1900 may be used to implement the embodiment 1700 and other embodiments described above.

[0243] The device 1900 for intra prediction of a picture includes a detection unit 1901, a selection unit 1902, and a prediction unit 1903. The detection unit 1901 is configured to detect a filtering state of a block based on information in a sub-partition (ISP), where the filtering state of the block includes a no-smoothing state, a smoothing state, or a direction-dependent smoothing state. The selection unit 1902 is configured to select a set of coefficients of an interpolation filter based on a value of the filtering state of the block, where the set of coefficients of the interpolation filter are fG coefficients or fC coefficients. The prediction unit 1903 is configured to obtain a predicted sample of a current block by applying the set of coefficients to a reference sample.

[0244] A selection unit 1902 configured to determine a filter flag (filterFlag) based on a filtering state of the block, where a value of the filterFlag indicates that a set of coefficients of the interpolation filter are fG coefficients or fC coefficients, and to select a set of coefficients of the interpolation filter based on the value of the filter flag.

[0245] a prediction unit 1903 configured to determine interpolation filter coefficients from a set of coefficients of an interpolation filter based on an intra-prediction mode of the current block, and obtain a predicted sample of the current block by applying the determined interpolation filter coefficients to a reference sample.

[0246] The present disclosure provides the following set of embodiments or aspects.

[0247] Embodiment 1. A method of intra smoothing for intra prediction of a block, comprising: determining a smoothing state for the block, the smoothing state including no smoothing, smoothing, or direction-dependent smoothing; Depending on the smoothing state of the block, the following steps are performed: When the smoothing state is direction-dependent smoothing, using the direction slope and the number of samples in the block to be predicted to determine the intra-smoothing method; When the smoothing state is no smoothing, not using any of the intra smoothing methods, or When the smoothing state is smooth, using a default combination of intra smoothing methods based on the number of samples in the block to be predicted. A method comprising the step of:

[0248] Embodiment 2. An intra smoothing method comprising the following steps: Adjustment of the strength of filtering of reference samples, Adjust the strength of the interpolation filtering, or ○ Existence of PDPC stage 2. The method of embodiment 1, comprising one or more of:

[0249] Embodiment 3. The method of embodiment 1 or 2, wherein the directional gradient is defined from the prediction mode index as Min(Abs(predModeIntra - 50), Abs(predModeIntra - 18)).

[0250] Embodiment 4. The method of embodiment 1 or 2, wherein the directional gradient is defined as Abs(predIntraAng) from the parameters predIntraAng.

[0251] Embodiment 5. Intra prediction is as follows: - Intrasubdivision (ISP), - Mode Dependent Intra Smoothing (MDIS), - Wide Angle Intra Prediction (WAIP), - Multi-Reference Line Prediction (MRLP), or - Position-dependent intra-prediction combining (PDPC) 5. The method of any of the preceding claims, comprising one or more of:

[0252] Embodiment 6. The method of embodiment 5, wherein the ISP flag is taken into account when the smoothing state is direction-dependent smoothing.

[0253] Embodiment 7. The method of embodiment 5 or 6, wherein the state of filtering is not set to no filtering when the intra prediction mode is INTRA_DC, the reference index of the MRLP is not equal to 0, or a chroma component is processed.

[0254] Embodiment 8. Unified intra prediction: - block aspect ratio, - the length of the main reference side, - Intra prediction mode, or - Intra subdivision 8. The method of any of the preceding claims, based on one or more of the following:

[0255] Embodiment 9. Parsing one or more flags from a bitstream; 9. The method of any of the preceding embodiments, further comprising: determining whether to perform intra smoothing based on one or more flags.

[0256] As discussed above, when the ISP is on, the embodiment of the present invention removes the mode dependency during the selection of the type of the interpolation filter. When the ISP is on, the value of filterFlag is 0, and the type of the interpolation filter fC is selected. The embodiment of the present invention provides a technical solution with a shorter path or pass path, which is comparable to the mode-dependent method in the normal case. This can increase the efficiency of the encoding or decoding, and further lead to the unification of the decision-making steps.

[0257] The following is a description of the application of the encoding and decoding methods illustrated in the above embodiments and the systems using them.

[0258] 20 is a block diagram showing a content supply system 3100 for realizing a content distribution service. The content supply system 3100 includes a capture device 3102, a terminal device 3106, and optionally a display 3126. The capture device 3102 communicates with the terminal device 3106 via a communication link 3104. The communication link may include the communication channel 13 described above. The communication link 3104 includes, but is not limited to, WIFI, Ethernet, cable, wireless (3G / 4G / 5G), USB, or any kind of combination thereof, etc.

[0259] The capture device 3102 may generate data and encode the data according to the encoding method shown in the above embodiment. Alternatively, the capture device 3102 may deliver the data to a streaming server (not shown), which encodes the data and transmits the encoded data to the terminal device 3106. The capture device 3102 includes, but is not limited to, a camera, a smartphone or smart pad, a computer or laptop, a video conference system, a PDA, an in-vehicle device, or any combination thereof. For example, the capture device 3102 may include the above-mentioned source device 12. When the data includes video, a video encoder 20 included in the capture device 3102 may actually perform the video encoding process. When the data includes audio (i.e., voice), an audio encoder included in the capture device 3102 may actually perform the audio encoding process. For some practical scenarios, the capture device 3102 delivers the encoded video and audio data by multiplexing them together. For other practical scenarios, for example, in a video conference system, the encoded audio data and the encoded video data are not multiplexed. The capture device 3102 delivers the encoded audio data and the encoded video data separately to the terminal device 3106 .

[0260] In the content supply system 3100, the terminal device 310 receives and plays the encoded data. The terminal device 3106 can be a device with data receiving and restoring capabilities, such as a smartphone or smart pad 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a TV 3114, a set-top box (STB) 3116, a video conferencing system 3118, a video surveillance system 3120, a personal digital assistant (PDA) 3122, an in-vehicle device 3124, or any combination thereof, that can decode the above-mentioned encoded data. For example, the terminal device 3106 may include the above-mentioned destination device 14. When the encoded data includes video, the video decoder 30 included in the terminal device is prioritized to perform video decoding. When the encoded data includes audio, the audio decoder included in the terminal device is prioritized to perform audio decoding processing.

[0261] For a terminal device having a display, such as a smartphone or smart pad 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a TV 3114, a personal digital assistant (PDA), or an in-vehicle device 3124, the terminal device can provide the decoded data to the display of the terminal device. For a terminal device without a display, such as an STB 3116, a video conferencing system 3118, or a video surveillance system 3120, an external display 3126 is contacted to receive and show the decoded data.

[0262] When each device in the system performs encoding or decoding, the picture encoding device or picture decoding device shown in the above embodiments may be used.

[0263] 21 is a diagram illustrating an example structure of a terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, a protocol progression unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, Real Time Streaming Protocol (RTSP), Hypertext Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real Time Transport Protocol (RTP), Real Time Messaging Protocol (RTMP), or any kind of combination thereof, etc.

[0264] After the protocol proceeding unit 3202 processes the stream, a stream file is generated. The file is output to the demultiplexing unit 3204. The demultiplexing unit 3204 can separate the multiplexed data into encoded audio data and encoded video data. As mentioned above, for some practical scenarios, for example, in a video conference system, the encoded audio data and the encoded video data are not multiplexed. In this situation, the encoded data is sent to the video decoder 3206 and the audio decoder 3208 without passing through the demultiplexing unit 3204.

[0265] The demultiplexing process generates a video elementary stream (ES), an audio ES, and optionally subtitles. The video decoder 3206, including the video decoder 30 described in the above embodiment, decodes the video ES by the decoding method shown in the above embodiment to generate video frames, and supplies the data to the synchronization unit 3212. The audio decoder 3208 decodes the audio ES to generate audio frames, and supplies the data to the synchronization unit 3212. Alternatively, the video frames may be stored in a buffer (not shown in Figure Y) before supplying the video frames to the synchronization unit 3212. Similarly, the audio frames may be stored in a buffer (not shown in Figure Y) before supplying the audio frames to the synchronization unit 3212.

[0266] The synchronization unit 3212 synchronizes the video and audio frames and provides the video / audio to a video / audio display 3214. For example, the synchronization unit 3212 synchronizes the presentation of video and audio information. The information may be coded in a syntax that uses timestamps for the presentation of the coded audio and visual data as well as timestamps for the delivery of the data stream itself.

[0267] If subtitles are included in the stream, a subtitle decoder 3210 decodes the subtitles, synchronizes the subtitles with the video and audio frames, and provides the video / audio / subtitles to a video / audio / subtitle display 3216 .

[0268] The present invention is not limited to the above-mentioned system, and either the picture encoding device or the picture decoding device of the above-mentioned embodiments may be incorporated into other systems, for example a system in an automobile.

[0269] Mathematical Operators The mathematical operators used in this application are similar to those used in the C programming language. However, the results of integer division and arithmetic shift operations are more precisely defined, and additional operations such as exponentiation and division of real values ​​are defined. The numbering and counting rules generally start at 0, e.g., "first" is equivalent to number 0, "second" is equivalent to number 1, and so on.

[0270] Arithmetic Operators The following arithmetic operators are defined as follows: + Add - subtraction (as a two-argument operator) or negation (as a unary prefix operator) * Multiplication, including matrix multiplication x y Exponentiation. Specifies x to the power of y. In other contexts, such notation is used to write superscripts that are not intended to be interpreted as powers. / Integer division with truncation of the result towards zero. For example, 7 / 4 and -7 / -4 round down to 1, and -7 / 4 and 7 / -4 round down to -1. ÷ Used to represent division in mathematical equations where truncation or rounding is not intended.

number

number

[0271] Logical Operators The following logical operators are defined as follows: x && y The Boolean logic "intersection" of x and y x || y The Boolean logic "union" of x and y Boolean logic "negation" x ? y : zIf x is true or not equal to 0, evaluates to the value y, otherwise it evaluates to the value z.

[0272] Relational Operators The following relational operators are defined as follows: > Greater than >= Greater than or equal to < Less than <= Less than or equal == Equal != Not equal

[0273] When a relational operator is applied to a syntax element or variable that has been assigned the value "na" (not applicable), the value "na" is treated as a distinct value for the syntax element or variable. The value "na" is not considered equal to any other value.

[0274] Bitwise Operators The following bitwise operators are defined as follows: & Bitwise "and". When operating on integer arguments, it operates on the two's complement representation of the integer values. When operating on a binary argument that contains fewer bits than another argument, the shorter argument is extended by appending its more significant bits equal to zero. Bitwise "logical or". When operating on integer arguments, it operates on the two's complement representation of the integer values. When operating on a binary argument that contains fewer bits than another argument, the shorter argument is extended by appending its more significant bits equal to zero. ^ Bitwise "exclusive or". When operating on integer arguments, it operates on the two's complement representation of the integer values. When operating on a binary argument that contains fewer bits than another argument, the shorter argument is extended by appending its more significant bits equal to zero. x >> y Arithmetic right shift of the two's complement integer representation of x by y bits in binary. This function is defined only for non-negative integer values of y. The bit shifted into the most significant bit (MSB) as a result of the right shift has a value equal to the MSB of x before the shift operation. x << y Arithmetic left shift of the two's complement integer representation of x by y bits in binary. This function is defined only for non-negative integer values of y. The bit shifted into the least significant bit (LSB) as a result of the left shift has a value equal to 0.

[0275] Assignment operator The following arithmetic operators are defined as follows. = Assignment operator ++ Increment, i.e., x++ is equivalent to x = x + 1, and when used as an array index, it is evaluated with the value of the variable before the increment operation. -- Decrement, i.e., x-- is equivalent to x = x - 1, and when used as an array index, it is evaluated with the value of the variable before the decrement operation. += Increment by the specified amount, i.e., x += 3 is equivalent to x = x + 3, and x += (-3) is equivalent to x = x + (-3). -= Decrement by the specified amount, i.e., x -= 3 is equivalent to x = x - 3, and x -= (-3) is equivalent to x = x - (-3).

[0276] Range notation The following notations are used to specify a range of values. x = y..z x takes integer values from y to z, inclusive, where x, y, and z are integer values and z is greater than y.

[0277] Mathematical functions The following mathematical functions are defined.

Number

[0278] Asin( x ) The trigonometric arcsine function, operating on an argument x in the range of -1.0 to 1.0, inclusive, and with an output value in the range of -π÷2 to π÷2, inclusive, in radians. Atan(x) The trigonometric arctangent function that operates on the argument x and has an output value in the range -π÷2 to π÷2, inclusive, in radians.

number

number

number

number

number

number

[0279] Precedence of operations When precedence within an expression is not made explicit using parentheses, the following rules apply: - An operation with higher precedence is evaluated before any operation with lower precedence. - Operations of equal precedence are evaluated in order from left to right.

[0280] The table below specifies the precedence of operations from highest to lowest, with higher positions in the table indicating higher precedence.

[0281] With respect to operators that are also used in the C programming language, the precedence used herein is the same as that used in the C programming language.

[0282] [Table 12]

[0283] Text description of logical operations In the text, in the following forms: if( condition 0 ) Statement 0 else if( condition1 ) Statement 1 ... else / * Comment giving information about remaining conditions * / Statement n A statement of logical operation, mathematically written in the form: may be written as follows: As follows... / ...the following applies: - if condition 0, then statement 0 - Otherwise, if condition 1, then statement 1 - ... - otherwise (comment conveying information about the remaining conditions), statement n

[0284] Each "If ..., then ...; otherwise, ..." statement in the text is introduced by "So that ..." or "... the following applies" immediately followed by "If ..., then ...". The final condition of an "If ..., then ...; otherwise, ..." is always "Otherwise, ...". Alternately inserted "If ..., then ...; otherwise, ..." statements can be identified by matching the "So that ..." or "... the following applies" with the closing "Otherwise, ...".

[0285] In the text, in the following forms: if( condition0a && condition0b ) Statement 0 else if( condition 1a || condition 1b ) Statement 1 ... else Statement n A statement of logical operation, mathematically written in the form: may be written as follows: As follows... / ...the following applies: - Statement 0 if all of the following conditions are true: - Condition 0a - Condition 0b - Otherwise, if one or more of the following conditions are true, then statement 1 - Condition 1a - Condition 1b - ... - otherwise, statement n

[0286] In the text, in the following forms: if( condition 0 ) Statement 0 if( condition1 ) Statement 1 A statement of logical operation, mathematically written in the form: may be written as follows: If condition 0, then statement 0 If condition 1, then statement 1

[0287] It should be noted that, although embodiments of the present invention have been described primarily in terms of video coding, embodiments of coding system 10, encoder 20, and decoder 30 (and correspondingly system 10), as well as other embodiments described herein, may also be configured for still picture processing or coding, i.e., processing or coding of individual pictures independent of any preceding or successive pictures, similar to video coding. In general, when picture processing coding is limited to a single picture 17, only inter prediction units 244 (encoder) and 344 (decoder) may not be available. All other functions (also called tools or technologies) of the video encoder 20 and the video decoder 30, e.g., residual calculation 204 / 304, transform 206, quantization 208, inverse quantization 210 / 310, (inverse) transform 212 / 312, partitioning 262 / 362, intra prediction 254 / 354, and / or loop filter 220, 320, and entropy coding 270, and entropy decoding 304, may be equally used for processing still pictures.

[0288] For example, the encoder 20 and the decoder 30, and embodiments of the functionality described herein in relation to the encoder 20 and the decoder 30, for example, may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored on a computer-readable medium or transmitted over a communication medium as one or more instructions or codes and executed by a hardware-based processing unit. A computer-readable medium may include a computer-readable storage medium corresponding to a tangible medium, such as a data storage medium, or a communication medium, including any medium that facilitates the transfer of a computer program from one place to another, for example via a communication protocol. Thus, generally, a computer-readable medium may correspond to (1) a tangible computer-readable storage medium that is non-transitory, or (2) a communication medium, such as a signal or carrier wave. A data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and / or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

[0289] By way of example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly referred to as a computer-readable medium. For example, if the instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio wave, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio wave, and microwave are included in the definition of medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but instead cover non-transitory tangible storage media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks usually reproduce data magnetically while discs reproduce data optically using a laser. Combinations of the above should also be included within the scope of computer-readable media.

[0290] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term "processor" as used herein may refer to any of the above structures or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided in dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into a combined codec. Also, the techniques may be implemented entirely in one or more circuits or logic elements.

[0291] The techniques of the present disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chipset). Various components, modules, or units are described in this disclosure to highlight aspects of the functionality of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, the various units may be combined in a codec hardware unit or provided by a collection of interoperable hardware units including one or more processors as described above in conjunction with suitable software and / or firmware. [Explanation of symbols]

[0292] 10. Video coding system, coding system 12 Source Device 13 Encoded picture data, communication channel 14 Destination Device 16 Picture Source 17 Picture, Picture Data, Raw Picture, Raw Picture Data, Monochrome Picture, Color Picture, Current Picture 18 Preprocessor, preprocessing unit, picture preprocessor 19 Preprocessed Picture, Preprocessed Picture Data 20 Video Encoder, Encoder 21 Encoded picture data, encoded bitstream 22 Communication interface, communication unit 28 Communication interface, communication unit 30 Decoder, Video Decoder 31 Decoded picture data, decoded picture 32 Post-processor, post-processing unit 33 Post-processed picture data, post-processed picture 34 Display Devices 46 Processing Circuit 100 Video Encoder 201 Input, input interface 203 picture block, original block, current block, partitioned block, current picture block 204 Residual Calculation Unit, Residual Calculation 205 Residual Blocks, Residual 206 Conversion Processing Unit, Conversion 207 Conversion Factors 208 Quantization Unit, Quantization 209 Quantized Coefficients, Quantized Transform Coefficients, Quantized Residual Coefficients 210 Inverse quantization unit, inverse quantization 211 Dequantized coefficients, dequantized residual coefficients 212 Inverse Transform Processing Unit, (inverse) transform 213 Reconstructed residual block, dequantized coefficients, transform block 214 Reconstruction Unit, Adder, Combiner 215 reconstructed blocks 216 Buffers 220 Loop filter unit, loop filter 221 Filtered Block, Filtered Reconstructed Block 230 Decoded Picture Buffer (DPB) 231 Decoded Pictures 244 Inter Prediction Units 254 Intra Prediction Unit, Inter Prediction Unit, Intra Prediction 260 Mode Selection Unit 262 Division Unit, Division 265 prediction block, predictor 266 Syntax Elements 270 Entropy coding unit, entropy coding 272 Output, Output Interface 304 Entropy Decoding Unit, Residual Calculation, Entropy Decoding 309 Quantized Coefficients 310 Inverse quantization unit, inverse quantization 311 Dequantized Coefficients, Transform Coefficients 312 Inverse transformation processing unit, (inverse) transformation, output 313 Reconstructed Residual Blocks 314 Reconstruction Unit, Summer, Adder 315 Reconstructed Blocks 320 Loop filter, loop filter unit, loop filtering unit 321 Filtered Blocks, Decoded Video Blocks 330 Decoded Picture Buffer (DPB), Decoded Picture Buffer (DBP) 331 Decoded Pictures 344 Inter Prediction Units 354 Intra Prediction Unit, Intra Prediction 360 mode application unit 362 Division 365 predicted blocks 400 Video Coding Device 410 Incoming port, input port 420 Receiver Unit (Rx) 430 Processor, Logic Unit, Central Processing Unit (CPU) 440 Transmitter Unit (Tx) 450 outgoing port, outgoing port 460 Memory 470 Coding Module 500 devices 502 processor 504 Memory 506 Data 508 Operating Systems 510 Application Program 512 Bus 514 Secondary Storage 518 Display 1600 Method, embodiment 1700 Method, embodiment 1800 devices 1801 Acquired Units 1802 Selection Unit 1803 prediction units 1900 devices 1901 Detection Unit 1902 Selection Unit 1903 prediction units 3100 Contents Supply System 3102 Capture Device 3104 Communication Links 3106 Terminal Device 3108 Smartphones, smart pads 3110 Computers, laptops 3112 Network Video Recorder (NVR) / Digital Video Recorder (DVR) 3114 TV 3116 Set-top box (STB) 3118 Video Conference System 3120 Video Surveillance System 3122 Personal digital assistant (PDA) 3124 In-vehicle devices 3126 Display 3202 Protocol Progression Unit 3204 Demultiplexing Unit 3206 Video Decoder 3208 Audio Decoder 3210 Subtitle Decoder 3212 Synchronous Unit 3214 Video / Audio Display 3216 Video / Audio / Subtitle Display

Claims

1. 1. A method for intra prediction of a block of a picture, comprising: obtaining information in a subpartition (ISP), the information of the ISP indicating whether the ISP is used to split the current block; selecting a set of coefficients of an interpolation filter based on the information of the ISP, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients; and obtaining a predicted sample of the current block by applying the set of coefficients to a reference sample.

2. selecting the set of coefficients of the interpolation filter, determining a filtering state of a block to be a no smoothing state when the information of an ISP indicates that an ISP is used to split the current block; and selecting an fC coefficient when the filtering state of the block is a no smoothing state.

3. 3. The method of claim 2, wherein the information of an ISP is indicated by a flag IntraSubPartitionsSplitType, and an ISP is used to split the current block when IntraSubPartitionsSplitType != ISP_NO_SPLIT.

4. 4. The method according to claim 2 or 3, wherein the filtering state of the block is indicated by a flag smoothState, and the filtering state of the block is in a non-smoothed state when the value of smoothState is 0.

5. 5. The method of claim 4, wherein a value of a filterFlag indicates that the set of coefficients of the interpolation filter are fG coefficients or fC coefficients.

6. The method of claim 5 , wherein the value of filterFlag is equal to the value of smoothState, and the value of filterFlag indicates that an fC coefficient is selected.

7. The step of obtaining a predicted sample of the current block comprises: determining interpolation filter coefficients from the set of coefficients of the interpolation filter based on an intra-prediction mode of the current block; and obtaining predicted samples of the current block by applying the determined interpolation filter coefficients to reference samples.

8. 1. A method for intra prediction of a block of a picture, comprising: detecting a filtering state of a block based on information in a sub-partition (ISP), the filtering state of the block comprising a no smoothing state, a smoothing state, or a direction-dependent smoothing state; selecting a set of coefficients of an interpolation filter based on a value of a filtering state of the block, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients; and obtaining a predicted sample of the current block by applying the set of coefficients to a reference sample.

9. selecting the set of coefficients of the interpolation filter, determining a filter flag (filterFlag) based on a filtering state of the block, a value of filterFlag indicating that the set of coefficients of the interpolation filter are fG coefficients or fC coefficients; and selecting the set of coefficients of the interpolation filter based on the value of the filter flag.

10. 10. The method of claim 9, wherein when the filtering state of the block is a no smoothing state, the value of the filter flag is equal to the value of the filtering state of the block.

11. The method of claim 10, wherein the information of ISP is indicated by an ISP flag, and the filtering state of the block is a no smoothing state when the ISP flag is on.

12. 12. The method of claim 11, wherein the ISP flag is IntraSubPartitionsSplitType, and the ISP flag is on when IntraSubPartitionsSplitType != ISP_NO_SPLIT.

13. 13. The method according to any one of claims 8 to 12, wherein the state of filtering of the block is indicated by a flag smoothState, and the state of filtering of the block is in a non-smoothed state when the value of smoothState is 0.

14. the value of the filter flag is 0 when the filtering state of the block is a non-smoothing state; 13. A method according to any one of claims 9 to 12, comprising selecting an fC coefficient when the value of the filter flag is 0.

15. The step of obtaining a predicted sample of the current block comprises: determining interpolation filter coefficients from the set of coefficients of the interpolation filter based on an intra-prediction mode of the current block; and obtaining predicted samples of the current block by applying the determined interpolation filter coefficients to reference samples.

16. 1. A method for intra prediction of a block of a picture, comprising: The method comprises the step of obtaining predicted samples of said block by applying an interpolation filter to reference samples, a set of coefficients of said interpolation filter being determined by the following steps performed for each of the smoothing mechanisms: - obtaining a value of a flag indicating whether an intra prediction mechanism is applied; and - comparing said value of the obtained flag with a predetermined binary value. and wherein the determination of a set of coefficients is performed by selecting one of a predetermined set of coefficients, the selection being based on the determination being a result of a comparison of the value of the obtained flag with a predetermined binary value.

17. 17. The method of claim 16, wherein two predetermined sets of coefficients, a first set (fC) and a second set (fG), are defined, and the selection of one of the predetermined sets of coefficients is based on the decision, the decision being a binary value derived from the result of the comparison of the value of the obtained flag with a predetermined binary value, and when the decision is 1, the first set is selected and when the decision is 0, the second set is selected.

18. 18. The method of claim 17, wherein the decision is set to 0 when at least one of the values ​​of the obtained flags is not equal to a predetermined binary value, and otherwise the decision is set to 1.

19. When the decision is set equal to 1, the following steps are carried out to further update the value of said decision: - get the value of the intra prediction mode, - Obtaining the mode threshold based on the number of samples of the block to be predicted, setting the determination to 0 when the intra prediction mode is greater than the mode threshold.

20. The method of claim 18, wherein:

20. The intra prediction mechanism and corresponding predefined thresholds are as follows: - the multi-reference line prediction (MRLP) with the predetermined threshold (refIdx) is set to 0; - the intra subdivision (ISP) having the predetermined threshold is set to 0; 20. The method according to any one of claims 16 to 19, comprising at least one of the following:

21. 21. The method of claim 16, wherein the obtained flag is intraSubPartitionSplitType and the predetermined binary value is ISP_NO_SPLIT.

22. 22. The method according to any one of claims 16 to 21, wherein the step of obtaining the value of the flag indicating whether an intra prediction mechanism is applied is performed by parsing the bitstream.

23. one or more processors; and a non-transitory computer readable storage medium coupled to the processor and storing programming for execution by the processor, the programming, when executed by the processor, configuring the decoder to perform the method of any one of claims 1 to 22.

24. one or more processors; and a non-transitory computer-readable storage medium coupled to the processor and storing programming for execution by the processor, the programming, when executed by the processor, configuring the encoder to perform the method of any one of claims 1 to 22.

25. An encoder (20) including processing circuitry for carrying out the method of any one of claims 1 to 22.

26. A decoder (30) including processing circuitry for carrying out the method of any one of claims 1 to 22.

27. A computer program product comprising program code for carrying out the method according to any one of claims 1 to 22.

28. 1. A device for intra prediction of blocks of a picture, comprising: An acquisition unit configured to acquire information of an Intra-Partition (ISP), the information of the ISP indicating whether the ISP is used to split a current block; A selection unit configured to select a set of coefficients of an interpolation filter based on the information of an ISP, where the set of coefficients of the interpolation filter are fG coefficients or fC coefficients; a prediction unit configured to obtain a predicted sample of the current block by applying the set of coefficients to a reference sample.

29. The selection unit is determining a filtering state of a block to be a no smoothing state when the information of an ISP indicates that an ISP is used to split the current block; 30. The device of claim 28, configured to select an fC coefficient when a filtering state of the block is a no smoothing state.

30. 30. The device of claim 29, wherein the information of an ISP is indicated by a flag IntraSubPartitionsSplitType, and an ISP is used to split the current block when IntraSubPartitionsSplitType != ISP_NO_SPLIT.

31. 31. The device according to claim 29 or 30, wherein the state of filtering of the block is indicated by a flag smoothState, and the state of filtering of the block is in a no smoothing state when the value of smoothState is 0.

32. 32. The device of claim 31, wherein a value of a filterFlag indicates that the set of coefficients of the interpolation filter are fG coefficients or fC coefficients.

33. 33. The device of claim 32, wherein the value of filterFlag is equal to the value of smoothState, and the value of filterFlag indicates that an fC coefficient is selected.

34. The prediction unit comprises: determining interpolation filter coefficients from the set of coefficients of the interpolation filter based on an intra-prediction mode of the current block; 34. The device of claim 28, configured to obtain predicted samples of the current block by applying the determined interpolation filter coefficients to reference samples.

35. 1. A device for intra prediction of blocks of a picture, comprising: a detection unit configured to detect a filtering state of a block based on information in a sub-partition (ISP), the filtering state of the block comprising a no smoothing state, a smoothing state, or a direction-dependent smoothing state; a selection unit configured to select a set of coefficients of an interpolation filter based on a value of a filtering state of the block, the set of coefficients of the interpolation filter being fG coefficients or fC coefficients; a prediction unit configured to obtain a predicted sample of a current block by applying the set of coefficients to a reference sample.

36. The selection unit is determining a filter flag (filterFlag) based on a filtering state of the block, a value of filterFlag indicating that the set of coefficients of the interpolation filter are fG coefficients or fC coefficients; and 36. The device of claim 35, configured to select the set of coefficients of the interpolation filter based on the value of the filter flag.

37. 37. The device of claim 36, wherein when the filtering state of the block is a no smooth state, the value of the filter flag is equal to the value of the filtering state of the block.

38. 38. The device of claim 37, wherein the information of an ISP is indicated by an ISP flag, and the filtering state of the block is a no smoothing state when the ISP flag is on.

39. 40. The device of claim 38, wherein the ISP flag is IntraSubPartitionsSplitType and the ISP flag is on when IntraSubPartitionsSplitType != ISP_NO_SPLIT.

40. 40. The device of claim 35, wherein the state of filtering of the block is indicated by a flag smoothState, and the state of filtering of the block is in a non-smoothed state when the value of smoothState is 0.

41. the value of the filter flag is 0 when the filtering state of the block is a non-smoothing state; 41. The device of claim 36, wherein the device selects an fC coefficient when the value of the filter flag is 0.

42. The prediction unit comprises: determining interpolation filter coefficients from the set of coefficients of the interpolation filter based on an intra-prediction mode of the current block; 42. The device of any one of claims 35 to 41, configured to obtain predicted samples of the current block by applying the determined interpolation filter coefficients to reference samples.

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