Encoder, decoder, and corresponding method related to intra prediction mode

Abstract

1. A coding method performed by a decoding device or an encoding device, the method comprising: obtaining indication information regarding a luma position (cbWidth / 2, cbHeight / 2) of a current coding block relative to a top-left luma sample position (xCb, yCb) of the current coding block, wherein cbWidth represents a width of the current coding block of luma samples and cbHeight represents a height of the current coding block of luma samples; setting a value of a luma intra prediction mode associated with the current coding block to a first default value when the indication information indicates that matrix-based intra prediction (MIP) is to be applied to the luma sample at the luma position (cbWidth / 2, cbHeight / 2) relative to the top-left luma sample position (xCb, yCb) of the current coding block; and obtaining a value of a chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority of PCT Application No. PCT / EP2019 / 072611, filed on August 23, 2019, which claims the priority of PCT Application No. PCT / EP2019 / 069944, filed on July 24, 2019. Both applications are incorporated herein by reference.

[0002] Embodiments of the present application (disclosure) generally relate to the field of picture processing, and more particularly to performing the derivation of chroma intra - prediction modes by using the intra - prediction mode from the corresponding luma component.

Background Art

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

[0004] The amount of video data required to depict even relatively short videos can be quite large, which can pose difficulties when the data is to be streamed over a communication network having a limited bandwidth capacity or transmitted in some other way. Thus, video data is generally compressed before being transmitted over modern communication networks. The size of the video can also be a problem when the video is stored on a storage device, as memory resources may be limited. In many cases, video compression devices use software and / or hardware at the source to encode the video data before transmission or storage, thereby reducing the amount of data required to represent the digital video image. The compressed data is then received at the destination by a video decompression device that decodes the video data. Due to limited network resources and the ever-increasing demand for higher video quality, improved compression and decompression techniques that increase the compression ratio without sacrificing much or any picture quality are desirable. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

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

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

[0007] A first aspect of the present invention relates to a coding method implemented by a decoding device or an encoding device. The method includes the step of obtaining indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block, where cbWidth represents the width of the current coding block of the luma component and cbHeight represents the height of the current coding block of the luma component. Correspondingly, cbWidth / 2 represents half of the width of the current coding block of the luma component, and cbHeight / 2 represents half of the height of the current coding block of the luma component. The absolute position of the luma position (cbWidth / 2, cbHeight / 2) is (xCb + cbWidth / 2, yCb + cbHeight / 2), that is, the "center" of the corresponding luma prediction block.

[0008] The method further includes the step of setting the value of the intra prediction mode of the luma related to the current coding block to a default value when the indication information indicates that matrix-based intra prediction (MIP) is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, and the step of obtaining the value of the chroma intra prediction mode based on the value of the intra prediction mode of the luma of the current coding block.

[0009] Obtaining prediction mode information from a fixed position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of the mode MIP and the luma intra prediction mode are aligned when the partitioning of the luma component is different from that of the chroma component for a given block size (for example, when the dual-tree coding method is enabled). The position of the mode MIP represents the position where the MIP mode is obtained, and the position of the luma intra prediction mode represents the position where the luma intra prediction mode is obtained.

[0010] A second aspect of the present invention relates to a coding method implemented by a decoding device or an encoding device. The method includes a step of obtaining indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block, where cbWidth represents the width of the current coding block of the luma component and cbHeight represents the height of the current coding block of the luma component. Correspondingly, cbWidth / 2 represents half of the width of the current coding block of the luma component, and cbHeight / 2 represents half of the height of the current coding block of the luma component. The absolute position of the luma position (cbWidth / 2, cbHeight / 2) is (xCb + cbWidth / 2, yCb + cbHeight / 2), that is, the "center" of the corresponding luma prediction block.

[0011] The method further includes a step of setting the value of the intra prediction mode of luma related to the current coding block to a first default value when indication information indicates that the Intra Block Copy (IBC) mode or the palette mode is applied to the luma component at the position (cbWidth / 2, cbHeight / 2) of the luma sample at the upper left of the current coding block, and a step of obtaining the value of the chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

[0012] Obtaining the prediction mode information from the fixed position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of the mode IBC and the luma intra prediction mode are aligned when the partitioning of the luma component is different from the partitioning of the chroma component for a given block size (e.g., when the dual tree coding method is enabled). The position of the mode IBC represents the position where the IBC mode is obtained, and the position of the luma intra prediction mode represents the position where the luma intra prediction mode is obtained.

[0013] Alternatively, obtaining the prediction mode information from the fixed position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of the mode palette and the luma intra prediction mode are aligned when the partitioning of the luma component is different from the partitioning of the chroma component for a given block size (e.g., when the dual tree coding method is enabled). The position of the mode palette represents the position where the palette mode is obtained, and the position of the luma intra prediction mode represents the position where the luma intra prediction mode is obtained.

[0014] Aligning the positions of obtaining the mode information from the position (cbWidth / 2, cbHeight / 2) is necessary when the partitioning of the luma component is different from the partitioning of the chroma component for a given block size. Otherwise, it may cause undefined behavior as shown in Figure 7.

[0015] The method according to the first aspect of the present invention can be executed by the apparatus according to the third aspect of the present invention. The Device further features and implementation forms of are corresponding to the features and implementation forms of the Method according to the first aspect of the present invention.

[0016] The method according to the second aspect of the present invention can be executed by the apparatus according to the fourth aspect of the present invention. The Device further features and implementation forms of are corresponding to the features and implementation forms of the Method according to the second aspect of the present invention.

[0017] According to a fifth aspect, an embodiment of the present invention relates to an apparatus for decoding or encoding a video stream, and includes a processor and a memory. The memory stores instructions for causing the processor to execute the method according to the first aspect.

[0018] According to a sixth aspect, an embodiment of the present invention relates to an apparatus for decoding or encoding a video stream, and includes a processor and a memory. The memory stores instructions for causing the processor to execute the method according to the second aspect.

[0019] According to a seventh aspect, there is proposed a computer-readable storage medium storing instructions for causing one or more processors to code video data when executed. The instructions cause the one or more processors to execute the method according to the first or second aspect or any possible embodiment of the first or second aspect.

[0020] According to an eighth aspect, an embodiment of the present invention relates to a computer program including program code for executing the method according to the first or second aspect or any possible embodiment of the first or second aspect when executed on a computer.

[0021] According to a ninth aspect, an embodiment of the present invention is a device for obtaining an intra prediction mode of chroma, including one or more processors and a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, where the programming, when executed by the processors, obtains first indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of a current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block, where cbWidth represents the width of the current coding block of the luma component and cbHeight represents the height of the current coding block of the luma component, and configures the decoder to perform the obtaining, and the non-transitory computer-readable storage medium. Correspondingly, cbWidth / 2 represents half of the width of the current coding block of the luma component, and cbHeight / 2 represents half of the height of the current coding block of the luma component. The absolute position of the luma position (cbWidth / 2, cbHeight / 2) is (xCb + cbWidth / 2, yCb + cbHeight / 2), that is, the "center" of the corresponding luma prediction block.

[0022] When the first indication information indicates that matrix-based intra prediction (MIP) is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, set the value of the intra prediction mode of the luma related to the current coding block to a first default value, or when the first indication information indicates that MIP is not applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, the one or more processors are further configured to obtain second indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block.

[0023] When second indication information indicates that the intra-block copy (IBC) mode or the palette mode is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with reference to the top-left luma sample position (xCb, yCb) of the current coding block, one or more processors are further configured to set the value of the intra prediction mode of luma related to the current coding block to a second default value and obtain the value of the intra prediction mode of chroma based on the value of the intra prediction mode of luma of the current coding block.

[0024] Obtaining the first indication information from the fixed position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of mode MIP and the intra prediction mode of luma are aligned when the partitioning of the luma component is different from the partitioning of the chroma component for a given block size (e.g., when the dual-tree coding method is enabled). When the first indication information does not indicate that MIP is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2), obtaining the second indication information from the fixed position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of mode IBC and the intra prediction mode of luma are aligned when the partitioning of the luma component is different from the partitioning of the chroma component for a given block size (e.g., when the dual-tree coding method is enabled). Alternatively, obtaining the second indication information from the fixed position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of mode palette and the intra prediction mode of luma are aligned when the partitioning of the luma component is different from the partitioning of the chroma component for a given block size (e.g., when the dual-tree coding method is enabled).

[0025] Details of one or more embodiments are set forth in the accompanying drawings and the following description. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

[0026] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0027]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0028] Hereinafter, unless otherwise specified, the same reference signs refer to the same or at least functionally equivalent features.

[0029] In the following description, reference is made to the accompanying drawings which form a part hereof and which illustrate specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present invention may be used. It is understood that embodiments of the present invention may be used in other aspects and may include structural or logical changes not shown in the drawings. Accordingly, the following detailed description should not be construed in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0030] For example, it is understood that the disclosure related to the described method may also apply to a corresponding device or system configured to perform the method, and vice versa. For example, if one or more steps of a particular method are described, the corresponding device may include one or more units for performing the one or more steps of the described method, such as functional units (e.g., one unit for 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, if a particular device is described based on one or more units, such as functional units, the corresponding method may include one step for performing the functions of the one or more units (e.g., one step for performing the functions of 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. Further, it is understood that the features of the various exemplary embodiments and / or aspects described herein may be combined with each other unless otherwise specified.

[0031] Video coding generally refers to the processing of a sequence of pictures that form a video or 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 on the source side and generally involves processing the original video pictures (e.g., by compression) to reduce the amount of data required to represent the video pictures (for more efficient storage and / or transmission). Video decoding is performed on the destination side and generally involves performing the reverse process compared to the encoder to reconstruct the video pictures. Embodiments that refer to the "coding" of video pictures (or generally pictures) are understood to relate to the "encoding" or "decoding" of video pictures or respective video sequences. The combination of the encoding part and the decoding part is also called a codec (coding and decoding).

[0032] In the case of reversible video coding, it is possible to reconstruct the original video pictures (assuming no transmission loss or other data loss during storage or transmission), i.e., the reconstructed video pictures have the same quality as the original video pictures. In the case of irreversible video coding, further compression, e.g., by quantization, is performed to reduce the amount of data representing the video pictures, which cannot be fully reconstructed at the decoder, i.e., the quality of the reconstructed video pictures is lower or worse compared to the quality of the original video pictures.

[0033] Some video coding standards belong to the group of "irreversible hybrid video coders" (i.e., they combine spatial and temporal prediction in the sample domain and 2D transform coding for applying 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 the encoder, the video generally generates a prediction block using, for example, spatial (intra-picture) prediction and / or temporal (inter-picture) prediction, subtracts the prediction block from the current block (the block being currently processed / processed), obtains a residual block, transforms the residual block, and quantizes the residual block in the transform domain to reduce the amount of data to be transmitted (compressed), i.e., coded, at the block (video block) level. On the other hand, in the decoder, the reverse process compared to the encoder is applied to the coded or compressed block to reconstruct the current block for presentation. Further, the encoder duplicates the decoder's processing loop so that both generate the same prediction (e.g., intra and inter prediction) and / or reconstruction for processing, i.e., coding, subsequent blocks.

[0034] Hereinafter, embodiments of a video coding system 10, a video encoder 20, and a video decoder 30 will be described with reference to FIGS. 1 to 3.

[0035] FIG. 1A is a schematic block diagram showing an exemplary coding system 10 that may utilize the technology of the present application, e.g., a video coding system 10 (or simply coding system 10). The video encoder 20 (or simply encoder 20) and the video decoder 30 (or simply decoder 30) of the video coding system 10 show examples of devices that may be configured to perform the techniques according to various examples described in the present application.

[0036] As shown in FIG. 1A, the coding system 10 includes a source device 12 configured to provide, for example, encoded picture data 21 to a destination device 14 in order to decode the encoded picture data 13.

[0037] The source device 12 includes an encoder 20 and additionally, i.e., optionally, may include a picture source 16, a preprocessor (or preprocessing unit) 18, for example, a picture preprocessor 18, and a communication interface or communication unit 22.

[0038] The picture source 16 includes or may be any kind of picture capturing device, for example, a camera for capturing real-world pictures, and / or any kind of picture generating device, for example, a computer graphics processor for generating pictures animated by a computer, or any kind of other device for acquiring and / or providing real-world pictures, pictures generated by a computer (for example, screen content, virtual reality (VR) pictures), and / or any combination thereof (for example, augmented reality (AR) pictures). The picture source may be any kind of memory or storage for storing any of the above-described pictures.

[0039] Distinguished from the processing performed by the preprocessor 18 and the preprocessing unit 18, the picture or picture data 17 may also be referred to as raw picture or raw picture data 17.

[0040] The preprocessor 18 is configured to receive the (raw) picture data 17 and perform preprocessing on the picture data 17 to obtain the preprocessed picture 19 or preprocessed picture data 19. The preprocessing performed by the preprocessor 18 may include, for example, trimming, color format conversion (such as from RGB to YCbCr), color correction, or noise removal. It can be understood that the preprocessing unit 18 may be an optional component.

[0041] The video encoder 20 is configured to receive the preprocessed picture data 19 and provide the encoded picture data 21 (further details will be described below, for example, based on Figure 2).

[0042] The communication interface 22 of the source device 12 is configured to receive the encoded picture data 21 and transmit the encoded picture data 21 (or any further processed version thereof) via the communication channel 13 to another device, such as the destination device 14 or any other device, for storage or direct reconstruction.

[0043] The destination device 14 includes a decoder 30 (such as a video decoder 30), and additionally, that is, optionally, may include a communication interface or communication unit 28, a postprocessor 32 (or postprocessing unit 32), and a display device 34.

[0044] The communication interface 28 of the destination device 14 is configured to receive the encoded picture data 21 (or any further processed version thereof), for example, directly from the source device 12 or from any other source, such as a storage device, such as a storage device for the encoded picture data, and provide the encoded picture data 21 to the decoder 30.

[0045] Communication interfaces 22 and 28 may be configured to transmit or receive encoded picture data 21 or encoded data 13 between the source device 12 and the destination device 14 via a direct communication link, such as a direct wired or wireless connection, or via any type of network, such as a wired or wireless network or any combination thereof, or any type of private and public network, or any combination of any type thereof.

[0046] Communication interface 22 may be configured to process the encoded picture data, for example, by packaging the encoded picture data 21 into a suitable format, such as a packet, and / or using any type of encoding or processing of the transmission for transmission via a communication link or communication network.

[0047] Communication interface 28, which forms the counterpart of communication interface 22, may be configured to receive the transmitted data and process the transmitted data using any type of corresponding decoding or processing of the transmission and / or unpacking of the packaging to obtain the encoded picture data 21.

[0048] Both communication interface 22 and communication interface 28 may be configured as a unidirectional communication interface or a bidirectional communication interface indicated by an arrow regarding communication channel 13 in FIG. 1A pointing from the source device 12 towards the destination device 14, for example, to set up a connection, acknowledge and exchange any other information related to the communication link and / or data transmission, for example, the transmission of the encoded picture data, for example, by transmitting and receiving messages.

[0049] Decoder 30 is configured to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (further details are described below, for example, based on FIG. 3 or FIG. 5).

[0050] The post-processor 32 of the destination device 14 is configured to post-process the decoded picture data 31 (also referred to as the reconstructed picture data), for example, the decoded picture 31, to obtain the post-processed picture data 33, for example, the post-processed picture 33. The post-processing executed by the post-processing unit 32 may include, for example, color format conversion (for example, from YCbCr to RGB), color correction, trimming, or resampling, or any other processing for preparing the decoded picture data 31, for example, for display by the display device 34.

[0051] The display device 34 of the destination device 14 is configured to receive the post-processed picture data 33, for example, to display a picture to a user or viewer. The display device 34 may be any type of display for showing the reconstructed picture, for example, an integrated or external display or monitor, or may include such a display or monitor. 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, a liquid crystal on silicon (LCoS), a digital light processor (DLP), or any other type of display.

[0052] FIG. 1A shows the source device 12 and the destination device 14 as separate devices, but embodiments of the device may also include both or both functions, the source device 12 or corresponding function and the destination device 14 or corresponding function. In such embodiments, the source device 12 or corresponding function and the destination device 14 or corresponding function may be implemented using the same hardware and / or software or by separate hardware and / or software or any combination thereof.

[0053] As will be apparent to those skilled in the art based on the description, the functions of the different units or the presence and (exact) partitioning of the functions within the source device 12 and / or the destination device 14 shown in FIG. 1A may vary depending on the actual device and application.

[0054] The encoder 20 (e.g., video encoder 20) or decoder 30 (e.g., video decoder 30) or both the encoder 20 and decoder 30 may be implemented by a processing circuit as 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, or any combination thereof dedicated or otherwise to video coding. The encoder 20 may be implemented by the processing circuit 46 to embody various modules considered in relation to the encoder 20 of FIG. 2 and / or any other encoder system or subsystem described herein. The decoder 30 may be implemented by the processing circuit 46 to embody various modules considered in relation to the decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein. The processing circuit may be configured to perform various operations discussed later. As shown in FIG. 5, if the technology is implemented partially in software, the device may store instructions for the software on a suitable non-transitory computer-readable storage medium and execute the instructions in hardware using one or more processors to perform the technology of the present disclosure. Either the video encoder 20 or the video decoder 30 may be incorporated, for example, as part of a combined encoder / decoder (codec) within a single device as shown in FIG. 1B.

[0055] The source device 12 and the destination device 14 may include any of a wide range of devices, such as any type of handheld or fixed device, e.g., 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, etc., and may or may not use an operating system or may use any type of operating system. In some cases, the source device 12 and the destination device 14 may support wireless communication. Thus, the source device 12 and the destination device 14 may be wireless communication devices.

[0056] In some cases, the video coding system 10 shown in FIG. 1A is merely an example, and the techniques of the present 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 and simply encode data in memory and / or retrieve and decode data from memory.

[0057] For the sake of convenience of explanation, embodiments of the present invention are described herein by referring to, for example, the reference software of the next-generation video coding standard developed by the Joint Collaboration Team on Video Coding (JCT-VC) of the ITU-T Video Coding Experts Group (VCEG) and the ISO / IEC Moving Picture Experts Group (MPEG), such as High-Efficiency Video Coding (HEVC) or Versatile Video Coding (VVC). Those skilled in the art will understand that the embodiments of the present invention are not limited to HEVC or VVC.

[0058] Encoder and Encoding Method FIG. 2 shows a schematic block diagram of an exemplary video encoder 20 configured to implement the technology of the present application. In the example of FIG. 2, the video encoder 20 includes an input 201 (or input interface 201), a residual calculation unit 204, a conversion processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse conversion 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 encoding unit 270, and an output 272 (or 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 by a hybrid video codec.

[0059] The residual calculation unit 204, the conversion processing unit 206, the quantization unit 208, and the mode selection unit 260 may be regarded as forming the forward signal path of the encoder 20. On the other hand, the inverse quantization unit 210, the inverse conversion 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 regarded as forming the reverse signal path of the video encoder 20. The reverse signal path of the video encoder 20 corresponds to the signal path of the decoder (see the video decoder 30 in FIG. 3). The inverse quantization unit 210, the inverse conversion 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 regarded as forming the "built-in decoder" of the video encoder 20.

[0060] Picture & Picture Division (Picture & Block) The encoder 20 may be configured to receive, for example, picture 17 (or picture data 17) via input 201, for example, a sequence of pictures forming a video or a video sequence. The received picture or picture data may also be preprocessed picture 19 (or preprocessed picture data 19). For simplicity, the following description refers to picture 17. Picture 17 may also be referred to as the current picture or the picture to be coded (especially in video coding, to distinguish the current picture from other pictures, for example, the already encoded and / or decoded pictures of the same video sequence, i.e., the video sequence including the current picture).

[0061] (Digital) pictures can be considered or can be regarded as a two-dimensional array or matrix of samples having intensity values. The samples of the array may also be called pixels (a shortening of picture elements) 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, generally, three color components are used, that is, the picture may be represented or may include three sample arrays. In the RGB format or color space, the picture includes corresponding sample arrays of red, green, and blue. However, in video coding, each pixel generally includes a luminance component represented by luminance (luminance) and chrominance (chrominance) formats or color spaces, for example, Y (L may also be used instead) and two chrominance components represented by Cb and Cr, and is represented by YCbCr. The luminance (or short luma) component Y represents brightness or gray-level intensity (similar to a grayscale picture), while the two chrominance (or short chroma) components Cb and Cr represent chrominance or color information components. Therefore, a picture in the YCbCr format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (Cb and Cr). A picture in the RGB format may be converted or transformed into the YCbCr format, and vice versa, and the process is also known as color transformation or conversion. If the picture is monochrome, the picture may include only a luminance sample array. Therefore, the picture may be, for example, an array of luma samples in the monochrome format, or an array of luma samples and two corresponding arrays of chroma samples in the 4:2:0, 4:2:2, and 4:4:4 color formats.

[0062] An embodiment of the video encoder 20 may include a picture partitioning unit (not shown in FIG. 2) configured to partition picture 17 into a plurality of (usually non-overlapping) picture blocks 203. These blocks may also be referred to as root blocks, macroblocks (H.264 / AVC), or coding tree blocks (CTB) or coding tree units (CTU) (H.265 / HEVC and VVC). The picture partitioning unit may use the same block size with respect to a corresponding grid that defines all pictures and block sizes of the video sequence, or may vary the block size between pictures or subsets or groups of pictures and be configured to partition each picture into corresponding blocks.

[0063] In a further embodiment, the video encoder may be configured to directly receive blocks 203 of picture 17, for example, one, some, or all of the blocks that form picture 17. Picture block 203 may also be referred to as the current picture block or the picture block to be coded.

[0064] Similar to picture 17, picture block 203 is also or may be regarded as a two-dimensional array or matrix of samples having intensity values (sample values) but smaller in dimension than picture 17. In other words, block 203 may include, for example, one sample array (e.g., the luma array in the case of monochrome picture 17, or the luma or chroma arrays in the case of a color picture), or three sample arrays (e.g., the luma and two chroma arrays in the case of color picture 17), or any other number and / or type of arrays depending on the applied color format. The number of samples in the horizontal and vertical directions (or axes) of block 203 defines the size of block 203. Thus, the block may be, for example, an MxN (M columns × N rows) array of samples or an MxN array of transform coefficients.

[0065] The embodiment of the video encoder 20 shown in FIG. 2 may be configured to encode picture 17 block by block. For example, encoding and prediction may be performed for each block 203.

[0066] The embodiment of the video encoder 20 shown in FIG. 2 may be further configured to partition and / or encode a picture by using slices (also called video slices), where the picture may be partitioned into one or more (generally non-overlapping) slices or encoded using one or more (generally non-overlapping) slices, and each slice may include one or more blocks (e.g., CTUs).

[0067] The embodiment of the video encoder 20 shown in FIG. 2 may be further configured to partition and / or encode a picture by using tile groups (also called video tile groups) and / or tiles (also called video tiles), where the picture may be partitioned into one or more (generally non-overlapping) tile groups or encoded using one or more (generally non-overlapping) tile groups, and each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, and each tile may be, for example, rectangular in shape and may include one or more blocks (e.g., CTUs), e.g., complete or partial blocks.

[0068] Calculation of Residual The residual calculation unit 204 may be configured to calculate a residual block 205 (also called residual 205) based on a picture block 203 and a prediction block 265 (further details about the prediction block 265 will be given later) by, for example, subtracting the sample values of the prediction block 265 from the sample values of the picture block 203 for each sample (pixel by pixel) to obtain the residual block 205 in the sample region.

[0069] Conversion The conversion processing unit 206 may be configured to apply a conversion, such as a discrete cosine transform (DCT) or a discrete sine transform (DST), to the sample values of the residual block 205 to obtain conversion coefficients 207 in the conversion domain. The conversion coefficients 207, also referred to as conversion residual coefficients, may represent the residual block 205 in the conversion domain.

[0070] The conversion processing unit 206 may be configured to apply an integer approximation of DCT / DST, such as the conversion defined for H.265 / HEVC. Compared with the orthogonal DCT transform, such an integer approximation is generally scaled at a specific rate. To maintain the norm of the residual block processed by the forward and inverse transforms, an additional scaling factor is applied as part of the conversion process. The scaling factor is generally selected based on specific constraints such as the scaling factor being a power of 2 for shift operations, the bit depth of the conversion coefficients, and the trade-off between accuracy and implementation cost. For example, a specific scaling factor may be specified for the inverse transform by, for example, the inverse transform processing unit 212 (and the corresponding inverse transform by the inverse transform processing unit 312 in the video decoder 30, for example), and the corresponding scaling factor for the forward transform by the conversion processing unit 206 of the encoder 20 may be specified accordingly.

[0071] Embodiments of the video encoder 20 (each, the conversion processing unit 206) may, for example, output conversion parameters, such as a certain one or more conversions, such that the video decoder 30 may receive and use the conversion parameters for decoding, for example, as they are or as encoded or compressed by the entropy encoding unit 270.

[0072] Quantization The quantization unit 208 may be configured to obtain the quantized coefficient 209 by quantizing the transform coefficient 207, for example, by applying scalar quantization or vector quantization. The quantized coefficient 209 may also be referred to as the quantized transform coefficient 209 or the quantized residual coefficient 209.

[0073] The quantization process may reduce the bit depth associated with some or all of the conversion coefficients 207. For example, an n-bit conversion coefficient may be truncated to an m-bit conversion 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 scalings may be applied to achieve finer or coarser quantization. A smaller quantization step size corresponds to finer quantization, while a larger quantization step size corresponds to coarser quantization. The applicable quantization step size may be indicated by the quantization parameter (QP). The quantization parameter may be, for example, an index to a predefined set of applicable quantization step sizes. For example, a small quantization parameter may correspond to fine quantization (small quantization step size), 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. For example, the corresponding and / or inverse dequantization by the inverse quantization unit 210 may include multiplication by the quantization step size. Some standards, such as embodiments according to HEVC, may be configured to determine the quantization step size using the quantization parameter. Generally, the quantization step size may be calculated based on the quantization parameter using a fixed point approximation of an equation that includes division. Additional scaling 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 exemplary implementation, the scaling of the inverse transform and dequantization may be combined. Alternatively, a customized quantization table may be used, for example, signaled from the encoder to the decoder within the bitstream. Quantization is an irreversible operation, and the loss increases as the quantization step size increases.

[0074] Embodiments of the video encoder 20 (each quantization unit 208), for example, may be configured to output quantization parameters (QP) that are, for example, unchanged or encoded by the entropy encoding unit 270 so that the video decoder 30 may receive and apply the quantization parameters for decoding.

[0075] Inverse quantization The inverse quantization unit 210 is configured to apply inverse quantization of the quantization unit 208 to the quantized coefficients to obtain dequantized coefficients 211 by applying, for example, the inverse of the quantization method applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208. The dequantized coefficients 211, also referred to as dequantized residual coefficients 211, may correspond to the transform coefficients 207, although generally not identical due to loss caused by quantization.

[0076] 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, such as an inverse discrete cosine transform (DCT) or 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.

[0077] Reconstruction The reconstruction unit 214 (e.g., adder or summer 214) is configured to add the transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265 by adding, for example, the sample values of the reconstructed residual block 213 and the sample values of the prediction block 265 on a sample-by-sample basis to obtain a reconstructed block 215 in the sample domain.

[0078] Filtering The loop filter unit 220 (or simply "loop filter" 220) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or generally, to filter the reconstructed samples to obtain filtered samples. The loop filter unit is configured to, for example, smooth pixel transitions or otherwise improve the quality of the video. 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, such as a bilateral filter, an adaptive loop filter (ALF), sharpening, a smoothing filter, or a collaborative filter, or any combination thereof. The loop filter unit 220 is shown as an in-loop filter in FIG. 2, but 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 the filtered reconstructed block 221.

[0079] Embodiments of the video encoder 20 (each, the loop filter unit 220) may be configured to output the parameters of the loop filter, such as, for example, remaining as is or encoded by the entropy coding unit 270 (such as sample-adaptive offset information), so that the decoder 30 may receive and apply the same loop filter parameters or respective loop filters for decoding.

[0080] Decoded Picture Buffer The decoded picture buffer (DPB) 230 may be a memory for storing 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 various 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 the same current picture or different pictures, for example, other already filtered blocks of already reconstructed pictures, for example, already reconstructed and filtered blocks 221, and may provide, for example, for inter prediction, a fully 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). The decoded picture buffer (DPB) 230 may also be configured to store one or more non-filtered reconstructed blocks 215 or generally non-filtered reconstructed samples, or any other further processed version of the reconstructed blocks or samples, if, for example, the reconstructed blocks 215 are not filtered by the loop filter unit 220.

[0081] Mode Selection (Segmentation & Prediction) The mode selection unit 260 includes a classification unit 262, an inter prediction unit 244, and an intra prediction unit 254, and is configured to receive or obtain original picture data, for example, the original block 203 (the current block 203 of the current picture 17), and reconstructed picture data, for example, of the same (current) picture and / or one or more already decoded pictures from, for example, the decoded picture buffer 230 or other buffers (for example, a line buffer not shown), filtered and / or unfiltered reconstructed samples or blocks. The reconstructed picture data is used as reference picture data for prediction, for example, inter prediction or intra prediction, to obtain the prediction block 265 or predictor 265.

[0082] The mode selection unit 260 may be configured to determine or select a classification and a prediction mode (for example, an intra or inter prediction mode) for the prediction mode of the current block (without classification) and generate a corresponding prediction block 265 to be used for the calculation of the residual block 205 and the reconstruction of the reconstructed block 215.

[0083] Embodiments of the mode selection unit 260 may be configured to select a partitioning and prediction mode that provides the best match or, in other words, the minimum residual (the minimum residual means better compression for transmission or storage) or the minimum signaling overhead (the minimum signaling overhead means better compression for transmission or storage), or to consider or balance both, from, for example, the partitioning and prediction modes supported by the mode selection unit 260 or available to the mode selection unit 260. The mode selection unit 260 may be configured to determine the partitioning and prediction modes based on rate distortion optimization (RDO), i.e., to select the prediction mode that provides the minimum rate distortion. Terms such as "best," "minimum," "optimal," etc. in this context do not necessarily refer to the overall "best," "minimum," "optimal," etc., but may also refer to a criterion for termination or selection such as a value exceeding or falling below a threshold, or other constraints that lead to a potentially "sub-optimal selection" but satisfy complexity and processing time reduction.

[0084] In other words, the partitioning unit 262 may be configured to repeatedly use, for example, quad-tree partitioning (QT), binary partitioning (BT), or ternary-tree partitioning (TT), or any combination thereof, to partition the block 203 into smaller block partitions or sub-blocks (which also form blocks), and, for example, to perform prediction for each of the block partitions or sub-blocks. Mode selection may include selection of the tree structure of the partitioned block 203, and the prediction mode is applied to each of the block partitions or sub-blocks.

[0085] The partitioning and prediction processing (e.g., by the partitioning unit 260) and prediction processing (by the inter-prediction unit 244 and the intra-prediction unit 254) performed by the exemplary video encoder 20 are described in more detail below.

[0086] Partitioning The partitioning unit 262 may partition (or divide) the current block 203 into smaller compartments, for example, smaller blocks of square or rectangular size. These smaller blocks (which may also be referred to as sub-blocks) may be further partitioned into even smaller compartments. This is also called a tree partition or a hierarchical tree partition. For example, a root block at the root tree level 0 (hierarchical level 0, depth 0) may be recursively partitioned into, for example, two or more blocks at the next lower tree level, for example, nodes at tree level 1 (hierarchical level 1, depth 1), and these blocks may be further partitioned into two or more blocks at the next lower level, for example, tree level 2 (hierarchical level 2, depth 2), and so on until a termination criterion is met, for example, the maximum tree depth or the minimum block size is reached and the partitioning ends. Blocks that are not further partitioned are also called leaf blocks or leaf nodes of the tree. A tree using a partition into two compartments is called a binary tree (BT), a tree using a partition into three compartments is called a ternary tree (TT), and a tree using a partition into four compartments is called a quadtree (QT).

[0087] As described above, the term "block" as used herein may be a portion of a picture, particularly a portion of a square or rectangle. For example, in relation to HEVC and VVC, a block may be a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), and a transform unit (TU), and / or a corresponding block, for example, a coding tree block (CTB), a coding block (CB), a transform block (TB), or a prediction block (PB), or may correspond thereto.

[0088] For example, a coding tree unit (CTU) may be or may include the CTB of luma samples, two corresponding CTBs of chroma samples of a picture having three sample arrays, or the CTB of samples of a picture coded using three separate colour planes and syntax structures for coding monochrome pictures or samples. Correspondingly, a coding tree block (CTB) may be an NxN block of samples for some value of N such that the division of the constituent CTB is a partition. A coding unit (CU) may be or may include the coding block of luma samples, two corresponding coding blocks of chroma samples of a picture having three sample arrays, or the coding block of samples of a picture coded using three separate colour planes and syntax structures for coding monochrome pictures or samples. Correspondingly, a coding block (CB) may be an MxN block of samples for some values of M and N such that the division of the CTB into coding blocks is a partition.

[0089] 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 determination 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 the relevant 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.

[0090] For example, in an embodiment according to the currently developed latest video coding standard called Versatile Video Coding (VVC), a combined quadtree and binary tree (QTBT) partitioning is used, for example, to partition coding blocks. In the QTBT block structure, a CU can have either a square or rectangular shape. For example, a Coding Tree Unit (CTU) is first partitioned by a quadtree structure. The leaf nodes of the quadtree are further partitioned by a binary tree or a ternary (or triple) tree structure. The leaf nodes of the partitioning tree are called Coding Units (CUs), and their segmentation is used for prediction and transform 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, multiple partitions, for example, ternary partitions, may be used together with the QTBT block structure.

[0091] In one example, the mode selection unit 260 of the video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.

[0092] As described above, the video encoder 20 is configured to determine or select the best or optimal prediction mode from a set of (e.g., pre-determined) prediction modes. The set of prediction modes may include, for example, an intra prediction mode and / or an inter prediction mode.

[0093] Intra Prediction A set of intra prediction modes may include, for example, 35 different intra prediction modes defined in HEVC, such as non-directional modes like DC (or average) mode and planar mode, or directional modes, or, for example, 67 different intra prediction modes defined for VVC, such as non-directional modes like DC (or average) mode and planar mode, or directional modes.

[0094] The intra prediction unit 254 is configured to generate an intra prediction block 265 using the reconstructed samples of neighboring blocks of the same current picture according to an intra prediction mode among a set of intra prediction modes.

[0095] The intra prediction unit 254 (or generally the mode selection unit 260) is further configured to output, in the form of a syntax element 266, an intra prediction parameter (or generally information indicating a selected intra prediction mode for a block) to the entropy coding unit 270 for inclusion in the encoded picture data 21 so that, for example, the video decoder 30 may receive and use the prediction parameter for decoding.

[0096] Inter prediction A set of (or possible) inter prediction modes depends on available reference pictures (i.e., for example, DPB at least the previously at least partially decoded pictures stored in 230) as well as other inter prediction parameters, for example, whether the entire reference picture is used to search for the best matching reference block or only a part of the reference picture, for example, only the search window area around the area of the current block is used, and / or whether, for example, pixel interpolation, for example, half / semi-pel and / or quarter-pel interpolation, is applied.

[0097] In addition to the prediction modes described above, a skip mode and / or a direct mode may be applied.

[0098] The inter prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (neither shown in FIG. 2). The motion estimation unit is configured to receive or obtain, for motion estimation, the picture block 203 (the current picture block 203 of the current picture 17) and the decoded picture 231, or at least one or a plurality of already reconstructed blocks, for example, the reconstructed blocks of one or a plurality of other / different already decoded pictures 231. For example, the 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 or form part of a sequence of pictures forming the video sequence.

[0099] The encoder 20 may be configured to select, for example, reference blocks from a plurality of reference blocks of the same or different pictures among a plurality of other pictures, and provide the motion estimation unit with the reference picture (or reference picture index) and / or the offset (spatial offset) between the position (x, y coordinates) of the reference block and the position of the current block as inter prediction parameters. This offset is also called a motion vector (MV).

[0100] The motion compensation unit is configured to obtain, for example receive, an inter prediction parameter and perform an inter prediction based on or using the inter prediction parameter to obtain an 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 that perhaps performs interpolation with sub-pixel accuracy. Interpolation filtering may generate additional pixel samples from known pixel samples and thus potentially increase the number of candidate prediction blocks that may be used to code a picture block. When receiving a motion vector for a PU of a current picture block, the motion compensation unit may find a prediction block pointed to by the motion vector in one of the reference picture lists.

[0101] The motion compensation unit may also generate blocks for use by the video decoder 30 when decoding a picture block of a video slice and syntax elements associated with the video slice. In addition to or instead of the slice and respective syntax elements, tile groups and / or tiles and respective syntax elements may be generated or used.

[0102] Entropy coding The entropy encoding unit 270 is configured to apply, for example, an entropy encoding algorithm or method (e.g., variable length coding (VLC) method, context adaptive VLC (CAVLC), arithmetic coding method, 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 (non-compression) to the quantized coefficients 209, inter prediction parameters, intra prediction parameters, loop filter parameters, and / or other syntax elements, so as to obtain, for example, the encoded picture data 21 that can be output via the output 272 in the form of an encoded bitstream 21, such that the video decoder 30 can receive the parameters and use them for decoding. The encoded bitstream 21 may be transmitted to the video decoder 30 or stored in memory for later transmission or retrieval by the video decoder 30.

[0103] Alternative configurations of the video encoder 20 and other structures may be used to encode the video stream. For example, a non-transform-based encoder 20 may directly quantize the residual signal without the transform processing unit 206 for a particular block or frame. In another implementation, the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined in a single unit.

[0104] Decoder and Decoding Method Figure 3 shows an example of a video decoder 30 configured to implement the technology of the present application. The video decoder 30 is configured to receive, for example, encoded picture data 21 (e.g., an encoded bitstream 21) encoded by the encoder 20 in order to obtain the decoded picture 331. The encoded picture data or bitstream includes information for decoding data representing encoded picture blocks of an encoded video slice (and / or tile group or tile) and associated syntax elements, for example.

[0105] In the example of Figure 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., an adder 314), a loop filter 320, a decoded picture buffer ( DPB ) 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 perform a decoding path that is generally inverse to the encoding path described in relation to the video encoder 100 of Figure 2 in some examples.

[0106] As described in relation to the encoder 20, 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 344, and the intra prediction unit 354 are also regarded as forming the "built-in decoder" of the video encoder 20. Therefore, the inverse quantization unit 310 may be functionally identical to the inverse quantization unit 110, the inverse transform processing unit 312 may be functionally identical to the inverse transform processing unit 212, the reconstruction unit 314 may be functionally identical to the reconstruction unit 214, the loop filter 320 may be functionally identical to the loop filter 220, and the decoded picture buffer 330 may be functionally identical to the decoded picture buffer 230. Therefore, the descriptions given for each unit and function of the video 20 encoder are applied mutatis mutandis to each unit and function of the video decoder 30.

[0107] Entropy decoding The entropy decoding unit 304 analyzes the bitstream 21 (or generally the encoded picture data 21), for example, performs entropy decoding on the encoded picture data 21 to obtain, for example, the quantized coefficients 309 and / or the decoded coding parameters (not shown in FIG. 3), such as inter prediction parameters (e.g., reference picture index and motion vector), intra prediction parameters (e.g., intra prediction mode or index), transform parameters, quantization parameters, loop filter parameters, and / or any or all of other syntax elements. The entropy decoding unit 304 may be configured to apply a decoding algorithm or method corresponding to the encoding method described in relation to 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 the other parameters to other units of the decoder 30. The video decoder 30 may receive syntax elements at the video slice level and / or at the video block level. In addition to or in place of the slice and its respective syntax elements, tile groups and / or tiles and their respective syntax elements may be received and / or used.

[0108] Inverse quantization The inverse quantization unit 310 receives the quantization parameter (QP) (or generally information related to inverse quantization) and the quantized coefficients from the encoded picture data 21 (e.g., by the entropy decoding unit 304, e.g., by parsing and / or decoding), and is configured to apply inverse quantization based on the quantization parameter to the decoded quantized coefficients 309 to obtain the 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 the video encoder 20 for each video block within a video slice (or tile or tile group) to determine the degree of quantization and, similarly, the degree of inverse quantization to be applied.

[0109] Inverse transformation The inverse transform processing unit 312 receives the dequantized coefficients 311, which may also be referred to as transform coefficients 311, and is configured to apply a transform to the dequantized coefficients 311 to obtain the residual block 213 reconstructed in the sample region. The reconstructed residual block 213 may also be referred to as the transform block 313. The transform may be an inverse transform, e.g., inverse DCT, inverse DST, inverse integer transform, or a conceptually similar inverse transform process. The inverse transform processing unit 312 may be further configured to receive transform parameters or corresponding information from the encoded picture data 21 (e.g., by the entropy decoding unit 304, e.g., by parsing and / or decoding) to determine the transform to be applied to the dequantized coefficients 311.

[0110] Reconstruction The reconstruction unit 314 (e.g., adder or summer 314) may be configured to add the reconstructed residual block 313 to the prediction block 365, e.g., by adding the sample values of the reconstructed residual block 313 and the sample values of the prediction block 365, to obtain the reconstructed block 315 in the sample region.

[0111] Filtering (Either within or after the coding loop) The loop filter unit 320 is configured to filter the reconstructed block 315 to obtain a filtered block 321, for example, to smooth pixel transitions or otherwise improve the quality of the video. 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, for example, a bilateral filter, an adaptive loop filter (ALF), sharpening, a smoothing filter, or a joint filter, or any combination thereof. The loop filter unit 320 is shown in FIG. 3 as a in-loop filter, but in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

[0112] Decoded Picture Buffer Next, the decoded video block 321 of the picture is stored in a decoded picture buffer 330 that stores the decoded picture 331 for subsequent motion compensation with respect to other pictures and / or for outputting respectively on a display as a reference picture.

[0113] The decoder 30 is configured to output the decoded picture 311, for example, via output 312, for presentation or viewing by a user.

[0114] 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. Based on the segmentation and / or prediction parameters or respective information received from the encoded picture data 21 (for example, by the entropy decoding unit 304, for example, by analyzing and / or decoding), it performs the determination of segmentation or partitioning and prediction. The mode application unit 360 may be configured to perform prediction (intra or inter prediction) for each block based on the reconstructed picture, block, or respective samples (filtered or unfiltered) to obtain the prediction block 365.

[0115] 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., 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 vectors 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 to 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., the video may be coded using I, P, or B tile groups and / or tiles.

[0116] The mode application unit 360 is configured to determine prediction information regarding a video block of a current video slice by analyzing a motion vector or related information and other syntax elements, and to generate a prediction block regarding the current decoded video block using the prediction information. For example, the mode application unit 360 uses a part of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction) used to code a video block of a video slice, a slice type of inter prediction (e.g., B slice, P slice, or GPB slice), construction information regarding one or more of the reference picture lists for the slice, a motion vector regarding each inter-coded video block of the slice, a status of inter prediction regarding each inter-coded video block of the slice, and other information for decoding a video block within the current video slice. The same or similar may be applied by such embodiments for embodiments using a tile group (e.g., video tile group) and / or a tile (e.g., video tile) in addition to or as an alternative to a slice (e.g., video slice). For example, a video may be coded using I, P, or B tile groups and / or tiles.

[0117] An embodiment of the video decoder 30 shown in FIG. 3 may be configured to partition and / or decode a picture by using a slice (also referred to as a video slice), and the picture may be partitioned into one or more (generally non-overlapping) slices or decoded using one or more (generally non-overlapping) slices, and each slice may include one or more blocks (e.g., CTUs).

[0118] The embodiment of the 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 the picture may be partitioned into one or more (generally non-overlapping) tile groups or decoded using one or more (generally non-overlapping) tile groups, and each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, and each tile may, for example, be rectangular in shape and may include one or more blocks (e.g., CTUs), e.g., complete or partial blocks.

[0119] 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 the loop filtering unit 320. For example, a non-conversion-based decoder 30 may directly inverse quantize the residual signal without the inverse transform processing unit 312 for a particular block or frame. In another implementation, the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined in a single unit.

[0120] 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 interpolation filtering, motion vector derivation, or loop filtering, further operations such as Clip or Shift may be performed on the processing result of interpolation filtering, motion vector derivation, or loop filtering.

[0121] Note that further operations may be applied to the derived motion vectors of the current block (including, but not limited to, the control point motion vector in affine mode, affine, plane, sub-block motion vectors in ATMVP mode, temporal motion vector, etc.). For example, the value of the motion vector is constrained to a predetermined range according to its representation bits. If the representation bit of the motion vector is bitDepth, then the range is -2^(bitDepth-1) to 2^(bitDepth-1)-1, where "^" means exponentiation. For example, when bitDepth is set to be equal to 16, the range is -32768 to 32767, and when bitDepth is set to be equal to 18, the range is -131072 to 131071. For example, the value of the derived motion vector (e.g., the MV of four 4×4 sub-blocks within one 8×8 block) is constrained such that the maximum difference between the integer parts of the MVs of the four 4×4 sub-blocks is N pixels or less, such as 1 pixel or less. Here, two methods for constraining the motion vector according to bitDepth are provided.

[0122] Method 1: Remove the overflow MSB (Most Significant Bit) by a flow operation 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) Wherein, 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 represent intermediate values.

[0123] For example, when the value of mvx is -32769, after applying equations (1) and (2), the resulting value is 32767. In a computer system, decimal numbers are stored as two's complements. The two's complement of -32769 is 1,0111,1111,1111,1111 (17 bits), and then the MSB is discarded. Thus, 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).

[0124] 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)

[0125] The operation may be applied in the sum of mvp and mvd as shown in equations (5) to (8).

[0126] Method 2: Discard the overflow 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 respectively correspond to the three input values of the clipping process of the MV, and the definition of the function Clip3 is as follows. [Number]

[0127] FIG. 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.

[0128] The 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. The video coding device 400 may also include optical - electrical (OE) components and electro - optical (EO) components coupled to the incoming port 410, receiver unit 420, transmitter unit 440, and outgoing port 450 for the transmission or reception of optical or electrical signals.

[0129] Processor 430 is implemented by hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (e.g., as a multi-core processor), FPGA, ASIC, and DSP. Processor 430 communicates with incoming port 410, receiver unit 420, transmitter unit 440, outgoing port 450, and memory 460. Processor 430 includes coding module 470. Coding module 470 implements the disclosed embodiments described above. For example, coding module 470 implements, processes, prepares, or provides various coding operations. Thus, including coding module 470 significantly improves the functionality of video coding device 400 and results in the conversion of video coding device 400 to different states. Alternatively, coding module 470 is implemented as instructions stored in memory 460 and executed by processor 430.

[0130] 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 such programs when selected for program execution and for storing instructions and data read during program execution. 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).

[0131] FIG. 5 is a simplified block diagram of an apparatus 500 that may be used as either or both of the source device 12 and the destination device 14 of FIG. 1 according to an exemplary embodiment.

[0132] The processor 502 of the device 500 can be a central processing unit. Alternatively, the processor 502 can be any other type of one or more devices that can operate or process information, either existing or developed in the future. Although the disclosed implementation can be carried out by a single processor, such as the processor 502 as shown, advantages in terms of speed and efficiency can be realized by using two or more processors.

[0133] The memory 504 of the device 500 can be a read-only memory (ROM) device or a random access memory (RAM) device in the 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 are accessed by the processor 502 using the bus 512. The memory 504 can further include an operating system 508 and an application program 510, and the application program 510 includes at least one program that enables the processor 502 to execute the methods described herein. For example, the application program 510 can include applications 1 to N that further include a video coding application that executes the methods described herein.

[0134] The device 500 can also include one or more output devices such as a display 518. In one example, the display 518 can be a touch display that is combined with a touch sensing element that is operable to sense touch input to the display. The display 518 can be coupled to the processor 502 via the bus 512.

[0135] Although shown here as a single bus, the bus 512 of the apparatus 500 can be composed of a plurality of buses. Further, the secondary storage 514 can be directly coupled to other components of the apparatus 500 or can be accessed via a network, and can include a single integrated unit such as a memory card or a plurality of units such as a plurality of memory cards. Therefore, the apparatus 500 can be implemented in a wide variety of configurations.

[0136] The background is related to the chroma intra prediction mode.

[0137] MIP (Matrix-based Intra Prediction) and IBC (Intra Block Copy) are two prediction methods. MIP performs intra prediction based on predefined coefficients. In IBC, sample values are predicted from other samples within the same picture using a displacement vector called a block vector in a manner conceptually similar to motion compensation prediction.

[0138] The palette mode is a coding tool for screen content coding (SCC) to improve the coding efficiency for screen content such as video generated by a computer having a significant amount of text and graphics. In the palette mode, pixels within a coding unit (CU) are represented by representative colors selected according to the characteristics of screen content where pixel values usually concentrate on a small number of color values.

[0139] In some examples, the MIP (or IBC or palette) mode is applied to the luma component. When using the DM mode to perform the derivation of the chroma intra prediction mode (deriving the mode from the corresponding luma component), when the corresponding luma block is applied with the MIP or IBC or palette mode, a special mode is assigned with respect to the DM mode (lumaIntraPredMode).

[0140] There are many documents referring to the derivation process of the chroma intra prediction mode. For example, ITU JVET - O0925 discloses the set chroma derive mode (DM) as the planar mode when the matrix - based intra prediction (MIP) is enabled, ITU JVET - O0258 discloses the disabled intra block copy (IBC) for chroma components, and ITU JVET - O0651 discloses the set chroma DM mode as DC when IBC is enabled.

[0141] In an example, the process for chroma derivation is as follows. The input to this process is - The luma position (xCb, yCb) that specifies the top - left sample of the current chroma coding block with reference to the top - left luma sample of the current picture - The variable cbWidth that specifies the width of the current coding block in luma samples - The variable cbHeight that specifies the height of the current coding block in luma samples

[0142] In this process, the chroma intra prediction mode IntraPredModeC[xCb][yCb] is derived.

[0143] The corresponding luma intra prediction mode lumaIntraPredMode is derived as follows. - When intra_mip_flag[xCb][yCb] is equal to 1, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, when CuPredMode[xCb][yCb] is equal to MODE_IBC, lumaIntraPredMode is set to be equal to INTRA_DC. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0144] In the above process, intra_mip_flag[xCb][yCb] equal to 1 specifies that the type of intra prediction for luma samples is matrix-based intra prediction, and intra_mip_flag[xCb][yCb] equal to 0 specifies that the type of intra prediction for luma samples is not matrix-based intra prediction.

[0145] CuPredMode[xCb][yCb] equal to MODE_IBC specifies that the current prediction block has the IBC mode applied.

[0146] IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2] specifies the luma intra prediction mode for the prediction block that includes the position (xCb + cbWidth / 2, yCb + cbHeight / 2), that is, the "center" of the corresponding luma prediction block.

[0147] In an example, the chroma intra prediction mode IntraPredModeC[xCb][yCb] is derived using intra_chroma_pred_mode[xCb][yCb] and lumaIntraPredMode as shown in Table 8-5 or Table 8-6, and there are many other examples or tables that may be used to derive the chroma intra prediction mode IntraPredModeC[xCb][yCb]. In the above process, intra_chroma_pred_mode[x0][y0] specifies the intra prediction mode (index) for chroma samples. Note that this intra prediction mode is not the final intra prediction mode, and it is more appropriate to consider this value as an intermediate index as an input to obtain the final intra prediction mode for chroma samples.

[0148] Table 8-5 - Specification of IntraPredModeC[xCb][yCb] determined according to intra_chroma_pred_mode[xCb][yCb] and lumaIntraPredMode when the value of sps_cclm_enabled_flag is equal to 0 [Table 1]

[0149] Table 8-6 - Specification of IntraPredModeC[xCb][yCb] determined according to intra_chroma_pred_mode[xCb][yCb] and lumaIntraPredMode when the value of sps_cclm_enabled_flag is equal to 1 [Table 2]

[0150] In Table 8-5 and Table 8-6 above, the sps_cclm_enabled_flag equal to 0 specifies that the cross-component linear model (CCLM) intra prediction from the luma component to the chroma component is disabled. The sps_cclm_enabled_flag equal to 1 specifies that the cross-component linear model intra prediction from the luma component to the chroma component is enabled.

[0151] In the examples disclosed in the process above, the luma intra prediction mode (lumaIntraPredMode) is obtained, and then, for example, from the bitstream, the chroma intra prediction mode (intra_chroma_pred_mode) is obtained. According to the value of the luma intra prediction mode (lumaIntraPredMode) and the value of the syntax intra_chroma_pred_mode, the output prediction mode is derived by Table 8-5 and Table 8-6.

[0152] In some examples, according to Table 8-5 and Table 8-6, the output mode may be one of 70 modes. The 70 modes may be classified into 67 normal modes and 3 cross-component linear model (CCLM) modes. The 67 normal modes may be further divided into non-angle modes (plane and DC modes) and 65 angle modes (modes 2 to 66) as shown in FIG. 6. Modes 81, 82, 83 correspond to 3 CCLM (cross-component linear model) modes corresponding to linear mode left and top (INTRA_LT_CCLM), linear mode left (INTRA_L_CCLM), and linear mode top (INTRA_T_CCLM). These modes are summarized in Table 8-3.

[0153]

Table 3

[0154] The shift between the position of the MIP (or IBC) flag and the position of the luma intra prediction mode may cause potential problems in the derivation of the chroma intra prediction mode.

[0155] That is, while the flag of intra_mip_flag (or CuPredMode) is fetched from the luma position (xCb, yCb), the intra prediction mode of the luma block is fetched from the position (xCb + cbWidth / 2, yCb + cbHeight / 2) as follows (as defined in the VVC process for the derivation of the chroma intra prediction mode). - When the value of intra_mip_flag[xCb][yCb] is equal to 1, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, when CuPredMode[xCb][yCb] is equal to MODE_IBC, lumaIntraPredMode is set to be equal to INTRA_DC. - In other cases, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0156] When CuPredMode[xCb][yCb] is equal to MODE_IBC, the intra prediction mode is not defined in the working draft of VVC.

[0157] In the example shown in FIG. 7, the partitioning of the prediction blocks of luma and chroma in a coding area (for example, the coding area is a CTU) is not aligned when the dual-tree coding method is enabled (one tree partition for luma and one tree partition for chroma). For simplicity, it is assumed that the chroma component within the CTU is divided into two parts by the lower left partition and the lower right partition (the left CTU in FIG. 7). However, the luma component within the CTU is also divided into two parts by the upper lower partition and the lower lower partition. The upper lower partition of the luma component has the normal intra prediction mode applied, and the lower lower partition has the IBC mode applied (the right CTU in FIG. 7).

[0158] In this example shown in FIG. 7, the chroma component is performing the derivation of the chroma intra prediction mode. According to the VVC process of the derivation of the previously defined chroma intra prediction mode, since the normal intra prediction mode is applied to the upper sub - partition within the luma component whose upper - left position is (xCb, yCb), the value of intra_mip_flag[xCb][yCb] is equal to 0. When the position (xCb, yCb) belongs to the upper and lower sub - partitions of the luma component and the block is applied with normal intra prediction, for the same reason, CuPredMode[xCb][yCb] is also not equal to MODE_IBC. Therefore, the derivation of the chroma intra prediction mode fetches the value of the normal luma intra prediction mode at (xCb + cbWidth / 2, yCb + cbHeight / 2) (that is, IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2]). However, here, the position (xCb + cbWidth / 2, yCb + cbHeight / 2) refers to a position within the lower - lower sub - partition of the luma component (as shown in the lower CTU of FIG. 7). The lower - lower sub - partition of the luma component has IBC applied and the luma intra prediction mode is not defined. Therefore, the value of IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2] is an undefined value in the current specification. In this rarely occurring troublesome case, the chroma intra prediction mode derivation process breaks down.

[0159] The example taken in FIG. 7 shows a rarely occurring troublesome case where two sub - partitions of the luma component are respectively applied with the normal intra prediction mode and the IBC mode. When IBC is replaced by the MIP or palette mode, the chroma derivation process can also be presumed to break down.

[0160] The luma position (xCb, yCb) that specifies the upper - left sample of the current chroma coding block with reference to the upper - left luma sample of the current picture.

[0161] The value (xCb, yCb) of the luma position with respect to the upper left position of the chroma component of the current coding block is obtained, the value of the luma position (xCb, yCb) is specified in the luma samples of the current coding block, the value of the first instruction information (e.g., intra_mip_flag) regarding the current coding block is obtained, and the value of the first instruction information regarding the current coding block corresponding to the luma position (cbWidth / 2, cbHeight / 2) is derived based on the upper left luma sample of the current coding block, where cbWidth represents the width of the current coding block in luma samples and cbHeight represents the height of the current coding block in luma samples (in the example, the first instruction information is derived from the luma position (xCb + cbWidth / 2, yCb + cbHeight / 2)).

[0162] As an example shown in FIG. 8, the value of the position with respect to the upper left position of the current picture is (0, 0), and the value of the position with respect to the upper left position of the current coding block is (128, 64). The width of the current coding block is 64, and the height of the current coding block is 32. Therefore, the value of the position used to derive the intra prediction mode is ((128 + 64 / 2), 64 + 32 / 2)), that is, (160, 80).

[0163] In an embodiment of the present invention, the position of the IBC or MIP flag is aligned with the position of the luma intra prediction mode, and the following process is applied. - When the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, when CuPredMode[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC, lumaIntraPredMode is set to be equal to INTRA_DC. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0164] In such a case, taking Figure 7 as an example again, the derivation of the chroma intra prediction mode falls into the second branch (that is, otherwise, when CuPredMode[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC), and lumaIntraPredMode is set to be equal to the DC mode.

[0165] The method is first detected using the aligned positions of IBC and MIP modes, thus ensuring that the variable lumaIntraPredMode is always assigned a valid luma intra prediction mode.

[0166] In one embodiment, the positions of the IBC or MIP flags are aligned with the positions of the luma intra prediction mode, their corresponding intra prediction modes are both set to the planar mode, and the following process is applied. - When the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1 or CuPredMode[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0167] In one embodiment, the positions of the IBC or MIP flags are aligned with the positions of the luma intra prediction modes, and their corresponding intra prediction modes are both set to the DC mode, and the following process is applied. - If the value of intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to 1 or CuPredMode[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to MODE_IBC, lumaIntraPredMode is set to be equal to INTRA_DC. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ].

[0168] In one embodiment of the present invention, the positions of the IBC or MIP flags are aligned with the positions of the luma intra prediction modes, and the following process is applied. - If the value of intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to 1, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, if CuPredMode

[0000] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to MODE_IBC, lumaIntraPredMode is set to be equal to INTRA_DC. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ].

[0169] In one embodiment of the present invention, the positions of the IBC or MIP or palette flags are aligned with the positions of the luma intra prediction modes, and the following process is applied. - When the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, when CuPredMode

[0000] [xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC or MODE_PLT, lumaIntraPredMode is set to be equal to INTRA_DC. - In other cases, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0170] In one embodiment of the present invention, the positions of the IBC or MIP or palette flag are aligned with the positions of the luma intra prediction mode, and the following process is applied. - When the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1 or when CuPredMode

[0000] [xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC or MODE_PLT, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0171] In one embodiment of the present invention, the positions of the IBC or MIP or palette flag are aligned with the positions of the luma intra prediction mode, and the following process is applied. - When the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1 or CuPredMode

[0000] [xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC or MODE_PLT, lumaIntraPredMode is set to be equal to INTRA_DC. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0172] In one embodiment of the present invention, the positions of the IBC or MIP or palette flag are aligned with the positions of the luma intra prediction mode, and the following process is applied. - When CuPredMode

[0000] [xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC or MODE_PLT, lumaIntraPredMode is set to be equal to INTRA_DC. - Otherwise, when the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1, lumaIntraPredMode is set to be equal to INTRA_PLANAR. - Otherwise, lumaIntraPredMode is set to be equal to IntraPredModeY[xCb + cbWidth / 2][yCb + cbHeight / 2].

[0173] In the above embodiment, CuPredMode[ xCb + cbWidth / 2][ yCb + cbHeight / 2 ] or CuPredMode[ i ][ xCb + cbWidth / 2][ yCb + cbHeight / 2 ] is used. In fact, they are the same, that is, they specify the prediction mode of the position (xCb + cbWidth / 2, yCb + cbHeight / 2) of the luma component. It should be noted that CuPredMode[ i ][ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is used with another dimension that specifies either the luma component or the chroma component, and i = 0 or 1. CuPredMode

[0000] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] represents the prediction mode of the luma component because the index of that dimension is 0. When the chroma channel is used, the corresponding variable is CuPredMode

[0001] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ].

[0174] In the above embodiment, when CuPredMode

[0000] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to MODE_PLT, it indicates that the luma component at the luma position (cbWidth / 2, cbHeight / 2) uses the palette mode. The luma position (cbWidth / 2, cbHeight / 2) specifies the position based on the top - left luma sample of the current coding block. The top - left sample (xCb, yCb) of the current coding block specifies the position based on the top - left sample of the current picture.

[0175] An example of the luma position (xCb+cbWidth / 2, yCb+cbHeight / 2) is shown in FIG. 7, where xCb = 128, yCb = 64, cbWidth = 64, and cbHeight = 32.

[0176] In particular, the following methods and embodiments 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.

[0177] According to embodiment 900 (see FIG. 9), in step 901, the device obtains first indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block, where cbWidth represents the width of the current coding block of the luma component and cbHeight represents the height of the current coding block of the luma component. Correspondingly, cbWidth / 2 represents half of the width of the current coding block of the luma component, and cbHeight / 2 represents half of the height of the current coding block of the luma component. The absolute position of the luma position (cbWidth / 2, cbHeight / 2) is (xCb + cbWidth / 2, yCb + cbHeight / 2), that is, the "center" of the corresponding luma prediction block.

[0178] For example, the first indication information regarding the luma position (cbWidth / 2, cbHeight / 2) may be intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ].

[0179] In step 902, when the first indication information indicates that the matrix-based intra prediction MIP is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, the device sets the value of the intra prediction mode of the luma related to the current coding block to a first default value. For example, the first default value is the value of the planar mode.

[0180] When intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to 1, the first indication information indicates that MIP is applied to the luma component.

[0181] In step 903, when the first indication information indicates that MIP is not applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, the device obtains second indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block.

[0182] When intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to 0, the first indication information indicates that MIP is not applied to the luma component.

[0183] The second information regarding the luma position (cbWidth / 2, cbHeight / 2) may be CuPredMode

[0000] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ].

[0184] In step 905, when the second indication information indicates that the intra block copy (IBC) mode or the palette mode is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, the device sets the value of the intra prediction mode of the luma related to the current coding block to the second default value. For example, the second default value is the value of the DC mode.

[0185] When CuPredMode

[0000] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to MODE_IBC, the second indication information indicates that the IBC mode is applied to the luma component. When CuPredMode

[0000] [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to MODE_PLT, the second indication information indicates that the palette mode is applied to the luma component.

[0186] When the second indication information indicates that the IBC mode or the palette mode is not applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2), the intra prediction mode of luma related to the current coding block is set to be equal to the intra prediction mode of luma at the position [ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ], that is, IntraPredModeY[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ].

[0187] In step 907, the device obtains the value of the chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block. If the value of the luma intra prediction mode of the current coding block is the first default value indicated in step 902, the device obtains the value of the chroma intra prediction mode based on the first default value. If the value of the luma intra prediction mode of the current coding block is the second default value indicated in step 905, the device obtains the value of the chroma intra prediction mode based on the second default value.

[0188] Detailed information for deriving the chroma intra prediction mode by using the intra prediction mode from the corresponding luma component is shown in the above embodiments.

[0189] FIG. 10 shows an embodiment of device 1000. Device 1000 may be the video decoder 30 of FIG. 1A or the decoder 30 of FIG. 3, or may be the video encoder 20 of FIG. 1A or the encoder 20 of FIG. 2. Device 1000 may be used to implement embodiment 900 and the other embodiments described above.

[0190] Device 1000 for obtaining a chroma intra prediction mode includes an acquisition unit 1001, a setting unit 1002, and a chroma intra prediction mode unit 1003. The acquisition unit 1001 is configured to obtain first indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block. Here, cbWidth represents the width of the current coding block of the luma component, and cbHeight represents the height of the current coding block of the luma component. The setting unit 1002 is configured to set the value of the luma intra prediction mode related to the current coding block to a first default value when the first indication information indicates that matrix-based intra prediction (MIP) is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block.

[0191] When the first indication information indicates that MIP is not applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, the acquisition unit 1001 is further configured to obtain second indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block.

[0192] When second indication information indicates that the intra-block copy (IBC) mode or the palette mode is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with reference to the top-left luma sample position (xCb, yCb) of the current coding block, the setting unit 1002 is further configured to set the value of the intra prediction mode of luma related to the current coding block to a second default value.

[0193] The chroma intra prediction mode unit 1003 is configured to obtain the value of the chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

[0194] The present disclosure provides the following sets of embodiments or aspects. According to a first aspect, the present invention is a coding method implemented by a decoding device, obtaining a value of first indication information regarding a current coding block, wherein the value of the first indication information regarding the current coding block is derived from a luma component corresponding to the luma position (cbWidth / 2, cbHeight / 2) with reference to the top-left luma sample (xCb, yCb) of the current coding block, cbWidth represents the width of the current coding block in luma samples, and cbHeight represents the height of the current coding block in luma samples; when the value of the first indication information indicates that matrix-based intra prediction (MIP) is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with reference to the top-left luma sample (xCb, yCb) of the current coding block, setting the value of the intra prediction mode of luma related to the current coding block to a first default value; and obtaining the value of the chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

[0195] According to a second aspect, the present invention is a coding method implemented by a decoding device, comprising: obtaining a value of first indication information regarding a current coding block, wherein the value of the first indication information regarding the current coding block is derived from a luma component corresponding to a luma position (cbWidth / 2, cbHeight / 2) with reference to the top-left luma sample (xCb, yCb) of the current coding block, cbWidth represents the width of the current coding block in terms of luma samples, and cbHeight represents the height of the current coding block in terms of luma samples; when the value of the first indication information indicates that an intra block copy (IBC) mode or a palette mode is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2) with reference to the top-left luma sample (xCb, yCb) of the current coding block, setting the value of the intra prediction mode of luma related to the current coding block to a first default value; and obtaining a value of the intra prediction mode of chroma based on the value of the intra prediction mode of luma of the current coding block.

[0196] As discussed above, in the normal case related to MIP or IBC or palette (such as the example shown in FIG. 7), when the partition of the luma component is different from the partition of the chroma component (for example, when the dual-tree coding method is enabled), there is a shift between the position of the mode MIP (or IBC, or palette) and the position of the luma intra prediction mode. In the aspects and implementations of the present invention, obtaining the first indication information from the determined position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of the mode MIP and the luma intra prediction mode are aligned when the partition of the luma component is different from the partition of the chroma component at a given block size (for example, when the dual-tree coding method is enabled). When the first indication information does not indicate that MIP is applied to the luma component at the luma position (cbWidth / 2, cbHeight / 2), obtaining the second indication information from the determined position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of the mode IBC and the luma intra prediction mode are aligned when the partition of the luma component is different from the partition of the chroma component at a given block size (for example, when the dual-tree coding method is enabled). Alternatively, obtaining the second indication information from the determined position (cbWidth / 2, cbHeight / 2) of the corresponding luma component ensures that the positions of the mode palette and the luma intra prediction mode are aligned when the partition of the luma component is different from the partition of the chroma component at a given block size (for example, when the dual-tree coding method is enabled).

[0197] The following is an explanation of the application of the encoding method and decoding method shown in the above embodiments and the systems using them.

[0198] FIG. 11 is a block diagram showing a content supply system 3100 for realizing a content delivery service. This content supply system 3100 includes a capture device 3102, a terminal device 3106, and optionally includes 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 combination of these types.

[0199] The capture device 3102 may generate data and encode the data by the encoding method shown in the above embodiments. Alternatively, the capture device 3102 may deliver the data to a streaming server (not shown), and the server 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 a smart pad, a computer or a laptop, a video conferencing system, a PDA, an in-vehicle device, or any combination of these. For example, the capture device 3102 may include the above-described source device 12. When the data includes video, the video encoder 20 included in the capture device 3102 may actually perform video encoding processing. When the data includes audio (i.e., voice), the audio encoder included in the capture device 3102 may actually perform audio encoding processing. For some actual scenarios, the capture device 3102 distributes the encoded video and audio data by multiplexing them together. For other actual scenarios, for example, in a video conferencing system, the encoded audio data and the encoded video data are not multiplexed. The capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.

[0200] In content supply system 3100, terminal device 310 receives and plays back encoded data. Terminal device 3106 can be a device having data reception and restoration capabilities, such as smartphone or smart pad 3108, computer or laptop 3110, network video recorder (NVR) / digital video recorder (DVR) 3112, TV 3114, set-top box (STB) 3116, video conference system 3118, video surveillance system 3120, personal digital assistant (PDA) 3122, in-vehicle device 3124, or any combination thereof. For example, terminal device 3106 may include the above-described destination device 14. When the encoded data includes video, 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.

[0201] Regarding a terminal device having a display, such as smartphone or smart pad 3108, computer or laptop 3110, network video recorder (NVR) / digital video recorder (DVR) 3112, TV 3114, personal digital assistant (PDA), or in-vehicle device 3124, the terminal device can supply the decoded data to the display of the terminal device. Regarding a terminal device not equipped with a display, such as STB 3116, video conference system 3118, or video surveillance system 3120, it communicates with external display 3126, and the decoded data is received and shown.

[0202] When each device of this system performs encoding or decoding, the picture encoding device or picture decoding device shown in the above-described embodiments can be used.

[0203] Figure 12 shows the structure of an example of the terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, the protocol progress unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, the Real-Time Streaming Protocol (RTSP), the Hypertext Transfer Protocol (HTTP), the HTTP Live Streaming Protocol (HLS), MPEG-DASH, the Real-Time Transport Protocol (RTP), the Real-Time Messaging Protocol (RTMP), or any combination of these types.

[0204] After the protocol progress 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 described above, in some actual scenarios, for example, in a video conferencing 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.

[0205] Through the demultiplexing process, a video elementary stream (ES), an audio ES, and optionally subtitles are generated. 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 a video frame, and supplies this data to the synchronization unit 3212. The audio decoder 3208 decodes the audio ES to generate an audio frame, and supplies this data to the synchronization unit 3212. Alternatively, the video frame may be stored in a buffer (not shown in the figure) before supplying the video frame to the synchronization unit 3212. Similarly, the audio frame may be stored in a buffer (not shown in the figure) before supplying the audio frame to the synchronization unit 3212. 12 not shown in the figure) before supplying the audio frame to the synchronization unit 3212.12 It may be stored in a buffer (not shown).

[0206] The synchronization unit 3212 synchronizes video frames and audio frames and supplies video / audio to the video / audio display 3214. For example, the synchronization unit 3212 synchronizes the presentation of video information and audio information. The information may be coded in a syntax that uses time stamps for the presentation of coded audio data and visual data as well as time stamps for the delivery of the data stream itself.

[0207] When subtitles are included in the stream, the subtitle decoder 3210 decodes the subtitles, synchronizes the subtitles with video frames and audio frames, and supplies video / audio / subtitles to the video / audio / subtitle display 3216.

[0208] The present invention is not limited to the above-described system, and any of the picture encoding devices or picture decoding devices of the above-described embodiments can be incorporated into other systems, for example, an automotive system.

[0209] 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 real-valued division are defined. The numbering and counting rules generally start from 0. For example, "the first" is equivalent to number 0, "the second" is equivalent to number 1, and so on.

[0210] Arithmetic operators The following arithmetic operators are defined as follows. + Addition - Subtraction (as a two-argument operator) or negation (as a unary prefix operator) * Multiplication including matrix multiplication x yPower. Defines x to the power of y. In other contexts, such notation is used for superscript writing not intended to be interpreted as a power. / Integer division that truncates the result to zero. For example, 7 / 4 and -7 / -4 are truncated to 1, and -7 / 4 and 7 / -4 are truncated to -1. ÷ Used to represent division in a mathematical equation where truncation or rounding is not intended.

Number

Number

[0211] Logical operators The following logical operators are defined as follows. x && y The boolean logical 'product' of x and y x || y The boolean logical'sum' of x and y ! Boolean logical 'negation' x? y : z If x is true or not equal to 0, it is evaluated to the value y, otherwise it is evaluated to the value z.

[0212] Relational operators The following relational operators are defined as follows. > Greater than >= Greater than or equal to < Less than <= Less than or equal to == Equal to != Not equal to When a relational operator is applied to a syntactic element or variable to which the value "na" (not applicable) is assigned, the value "na" is treated as a distinct value with respect to the syntactic element or variable. The value "na" is considered not equal to any other value.

[0213] Bitwise operators The following bitwise operators are defined as follows. & Bitwise "logical AND". When operating on integer arguments, it acts on the two's complement representation of the integer values. When operating on a binary argument containing fewer bits than the other argument, the shorter argument is extended by adding leading bits equal to 0. | Bitwise "logical OR". When operating on integer arguments, it acts on the two's complement representation of the integer values. When operating on a binary argument containing fewer bits than the other argument, the shorter argument is extended by adding leading bits equal to 0. ^ Bitwise "exclusive OR". When operating on integer arguments, it acts on the two's complement representation of the integer values. When operating on a binary argument containing fewer bits than the other argument, the shorter argument is extended by adding leading bits equal to 0. x>>y Arithmetic right shift of the two's complement representation of the integer x by y binary digits. 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 the same value as the MSB of x before the shift operation. x<<y Arithmetic left shift of the two's complement representation of the integer x by y binary digits. 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.

[0214] Assignment operators The following arithmetic operators are defined as follows. = Assignment operator ++ Increment, that is, x++ is equivalent to x = x + 1, and when used as an index of an array, it is evaluated with the value of the variable before the increment operation. -- Decrement, that is, x-- is equivalent to x = x - 1, and when used as an index of an array, it is evaluated with the value of the variable before the decrement operation. += Increment by the specified amount, that is, x += 3 is equivalent to x = x + 3, and x += (-3) is equivalent to x = x + (-3). -= Decrement by the specified amount, that is, x -= 3 is equivalent to x = x - 3, and x -= (-3) is equivalent to x = x - (-3).

[0215] Range notation The following notations are used to specify a range of values. x = y..z x takes integer values from y to z, including y and z, assuming that x, y, and z are integer values and z is greater than y.

[0216] Mathematical functions The following mathematical functions are defined.

Number

Number

Math

Math

Math

Math

Math

Math

[0217] Operator Precedence When the precedence in the formula is not explicitly specified using parentheses, the following rules apply. - Operations with higher precedence are evaluated before any operations with lower precedence. - Operations with the same priority are evaluated in order from left to right.

[0218] The following table shows the operator priorities from highest to lowest, with higher positions in the table indicating higher priorities.

[0219] For operators also used in the C programming language, the precedence used in this specification is the same as that used in the C programming language.

[0220]

Table 4

[0221] Text description of logical operations In the text, in the following form, that is, if( condition 0 ) Statement 0 else if( condition 1 ) Statement 1 ... else / * Comment conveying information about the remaining conditions * / Statement n Logical operation statements mathematically described in the form of As follows... / ... The following applies. - In the case of condition 0, statement 0 - Otherwise, in the case of condition 1, statement 1 -... - In other cases (comment conveying information about the remaining conditions), statement n

[0222] In this document, each statement of "if..., then..., otherwise if..., otherwise..." is introduced by "as follows" or "the following applies" immediately following "if...". The last condition of "if..., then..., otherwise if..., otherwise..." is always "otherwise...". The statements of "if..., then..., otherwise if..., otherwise..." inserted alternately can be identified by matching "as follows" or "the following applies" with the ending "otherwise...".

[0223] In this document, in the following form, that is,[[]]END]] if( condition 0a && condition 0b ) Statement 0 else if( condition 1a || condition 1b ) Statement 1 ... else Statement n The logical operation statements described mathematically in the form of[[]]END]] As follows / The following applies.[[]]END]] - If all of the following conditions are true, Statement 0 - condition 0a - condition 0b - Otherwise, if one or more of the following conditions are true, Statement 1 - condition 1a - condition 1b -... - Otherwise, Statement n In this document, in the following form, that is,[[]]END]] if( condition 0 ) Statement 0 if( condition 1 ) Statement 1 A logical operation statement mathematically described in the form of may be described as follows. When condition 0, statement 0 When condition 1, statement 1

[0224] Although embodiments of the present invention have been mainly described based on video coding, embodiments of the coding system 10, the encoder 20, and the decoder 30 (and the system 10 corresponding thereto), as well as other embodiments described herein, may also be configured for the processing or coding of still pictures, i.e., the processing or coding of individual pictures independent of any preceding or successive pictures similar to video coding. Note that generally, when the processing coding of pictures is limited to a single picture 17, only the 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, for example, residual calculation 204 / 304, transformation 206, quantization 208, inverse quantization 210 / 310, (inverse) transformation 212 / 312, segmentation 262 / 362, intra prediction 254 / 354, and / or loop filters 220, 320, and entropy coding 270, and entropy decoding 304 may be equally used for the processing of still pictures.

[0225] For example, the encoder 20 and decoder 30, and embodiments of the functions described herein in connection with, for example, the encoder 20 and decoder 30 may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on a computer-readable medium as one or more instructions or code or transmitted over a communication medium and executed by a hardware-based processing unit. The 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 transfer of a computer program from one place to another, for example, by a communication protocol. Thus, generally, the 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. The 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.

[0226] By way of example and not limitation, such computer-readable storage media can 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 the desired program code in the form of instructions or data structures and that is accessible by a computer. Also, any connection can be properly termed 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, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but instead are directed to 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 disk typically magnetically reproduces data, while disc optically reproduces data using a laser. Combinations of the above should also be included within the scope of computer-readable media.

[0227] The commands 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. Accordingly, the term "processor" as used herein may refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. Additionally, in some aspects, the functions described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding or incorporated in a combined codec. Also, the techniques may be implemented entirely in one or more circuits or logic elements.

[0228] The techniques of the present disclosure may be implemented in a variety of devices or apparatuses including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chipset). Although various components, modules, or units are described in the present disclosure to emphasize aspects of the functionality of a device configured to execute the disclosed techniques, implementation by different hardware units is not necessarily required. Rather, as described above, the various units may be provided by a collection of interoperable hardware units including one or more of the foregoing processors combined in a codec hardware unit or cooperating with suitable software and / or firmware.

Explanation of Signs

[0229] 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 Postprocessor, postprocessing unit 33 Postprocessed picture data, postprocessed picture 34 Display device 46 Processing circuit 100 Video encoder 201 Input, input interface 203 Picture block, original block, current block, segmented block, current picture block 204 Residual calculation unit, residual calculation 205 Residual block, residual 206 Transformation processing unit, transformation 207 Transformation coefficient 208 Quantization unit, quantization 209 Quantized coefficient, quantized transformation coefficient, quantized residual coefficient 210 Inverse quantization unit, inverse quantization 211 Dequantized coefficient, dequantized residual coefficient 212 Inverse transformation processing unit, (inverse) transformation 213 Reconstructed residual block, inverse quantized coefficient, transformation block 214 Reconstruction unit, adder, summer 215 Reconstructed block 216 Buffer 220 Loop filter unit, loop filter 221 Filtered block, filtered reconstructed block 230 Decoded picture buffer (DPB) 231 Decoded picture 244 Inter prediction unit 254 Intra prediction unit, inter prediction unit, intra prediction 260 Mode selection unit 262 Partitioning unit, partitioning 265 Prediction block, predictor 266 Syntax element 270 Entropy coding unit, entropy coding 272 Output, output interface 304 Entropy decoding unit, residual calculation, entropy decoding 309 Quantized coefficient 310 Inverse quantization unit, inverse quantization 311 Dequantized coefficient, transform coefficient 312 Inverse transform processing unit, (inverse) transform, output 313 Reconstructed residual block 314 Reconstruction unit, adder, adder 315 Reconstructed block 320 Loop filter, loop filter unit, loop filtering unit 321 Filtered block, decoded video block 330 Decoded picture buffer (DPB), decoded picture buffer (DBP) 331 Decoded picture 344 Inter prediction unit 354 Intra prediction unit, intra prediction 360 Mode application unit 362 Partitioning 365 Prediction block 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 Transmission Port, Output Port 460 Memory 470 Coding Module 500 Device 502 Processor 504 Memory 506 Data 508 Operating System 510 Application Program 512 Bus 514 Secondary Storage 518 Display 900 Embodiment 1000 Device 1001 Acquisition Unit 1002 Setting Unit 1003 Chroma Intra Prediction Mode Unit 3100 Content Supply System 3102 Capture Device 3104 Communication Link 3106 Terminal Device 3108 Smartphone, Smart Pad 3110 Computer, Laptop 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 Device 3126 Display 3202 Protocol Progress Unit 3204 Multiplexing Separation Unit 3206 Video Decoder 3208 Audio Decoder 3210 Subtitle Decoder 3212 Synchronization Unit 3214 Video / Audio Display 3216 Video / Audio / Subtitle Display

Claims

Claim 1 A method for obtaining an intra prediction mode of chroma of a current coding block, implemented by a decoding device or an encoding device, wherein partitions of a luma component and partitions of a chroma component of the current coding block are not aligned in position, the method comprising: obtaining first indication information regarding a position (cbWidth / 2, cbHeight / 2) of luma of the current coding block, based on a top-left luma sample position (xCb, yCb) of the current coding block, where cbWidth represents a width of the current coding block of luma samples and cbHeight represents a height of the current coding block of the luma samples; when the first indication information indicates that matrix-based intra prediction (MIP) is applied to the luma sample at the position (cbWidth / 2, cbHeight / 2) of the luma, based on the top-left luma sample position (xCb, yCb) of the current coding block, setting a value of an intra prediction mode of the luma related to the current coding block to a first default value; when the first indication information indicates that the MIP is not applied to the luma sample at the position (cbWidth / 2, cbHeight / 2) of the luma, based on the top-left luma sample position (xCb, yCb) of the current coding block, obtaining second indication information regarding the position (cbWidth / 2, cbHeight / 2) of the luma of the current coding block; when the second indication information indicates that an intra block copy (IBC) mode or a palette mode is applied to the luma sample at the position (cbWidth / 2, cbHeight / 2) of the luma, based on the top-left luma sample position (xCb, yCb) of the current coding block, setting the value of the intra prediction mode of the luma related to the current coding block to a second default value; and obtaining a value of an intra prediction mode of chroma based on the value of the intra prediction mode of the luma of the current coding block. Claim 2 The method according to claim 1, wherein the first default value is equal to the value in the planar mode or the first default value is equal to the value in the DC mode.

3. The method according to claim 1, wherein the second default value is equal to the value in the DC mode or the value in the planar mode.

4. The absolute position of the luma at the position (cbWidth / 2, cbHeight / 2) is (xCb + cbWidth / 2, yCb + cbHeight / 2), and the absolute position (xCb + cbWidth / 2, yCb + cbHeight / 2) specifies the position based on the top-left sample of the current picture, and the position of the luma at (cbWidth / 2, cbHeight / 2) specifies the position based on the top-left luma sample position (xCb, yCb) of the current coding block. The method according to any one of claims 1 to 3.

5. The IBC mode or the palette mode is applied to the luma sample at the position (cbWidth / 2, cbHeight / 2), The method according to any one of claims 1 to 3, including that CuPredMode[0][xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC or MODE_PLT respectively.

6. The indication information indicates that the MIP is applied to the luma sample at the position (cbWidth / 2, cbHeight / 2), The method according to any one of claims 1 to 5, including that the value of intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1.

7. A device for obtaining the chroma intra prediction mode of the current coding block, wherein the partitions of the luma component and the chroma component of the current coding block are not aligned in position, and the device includes One or more processors, A non-transitory computer-readable storage medium coupled to the processor and storing programming for execution by the processor, wherein when the programming is executed by the processor, Obtaining first indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block with respect to the top-left luma sample position (xCb, yCb) of the current coding block, where cbWidth represents the width of the current coding block of luma samples and cbHeight represents the height of the current coding block of the luma samples, the obtaining, When the first indication information indicates that matrix-based intra prediction (MIP) is applied to the luma sample at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, setting the value of the intra prediction mode of the luma related to the current coding block to a first default value, When the first indication information indicates that the MIP is not applied to the luma sample at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, obtaining second indication information regarding the luma position (cbWidth / 2, cbHeight / 2) of the current coding block, When the second indication information indicates that the intra block copy (IBC) mode or the palette mode is applied to the luma sample at the luma position (cbWidth / 2, cbHeight / 2) with respect to the top-left luma sample position (xCb, yCb) of the current coding block, setting the value of the intra prediction mode of the luma related to the current coding block to a second default value, and A non-transitory computer-readable storage medium including a device configured to obtain a value of the chroma intra prediction mode based on the value of the intra prediction mode of the luma of the current coding block. A device.

8. The first indication information is intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ], and The device according to claim 7, wherein when intra_mip_flag[ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to 1, the first instruction information indicates that the MIP is applied to the luma sample.

9. The second instruction information is CuPredMode[ 0 ][ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ], The device according to claim 7 or 8, wherein when CuPredMode[ 0 ][ xCb + cbWidth / 2 ][ yCb + cbHeight / 2 ] is equal to MODE_IBC or MODE_PLT, the second instruction information indicates that the IBC mode or the palette mode is applied to the luma sample.

10. The device according to any one of claims 7 to 9, wherein the first default value is a value of the planar mode and the second default value is a value of the DC mode.

11. The device according to any one of claims 7 to 10, which is a decoder.

12. The device according to any one of claims 7 to 10, which is an encoder.

13. An encoder (20) including a processing circuit for executing the method according to any one of claims 1 to 6.

14. A decoder (30) including a processing circuit for executing the method according to any one of claims 1 to 6.

15. A computer program including program code for executing the method according to any one of claims 1 to 6.

16. A device for obtaining an intra prediction mode of a chroma of a current coding block, wherein partitions of a luma component and partitions of a chroma component of the current coding block are not aligned in position, and the device includes An acquisition unit (1001) configured to acquire first instruction information regarding a position (cbWidth / 2, cbHeight / 2) of luma of the current coding block with respect to a position (xCb, yCb) of a top-left luma sample of the current coding block, where cbWidth represents a width of the current coding block of the luma sample and cbHeight represents a height of the current coding block of the luma sample, the acquisition unit (1001); A setting unit (1002) configured to set the value of the intra prediction mode of the luma related to the current coding block to a first default value when the intra prediction based on the matrix (MIP) is applied to the luma sample at the position (cbWidth / 2, cbHeight / 2) of the luma with reference to the top-left luma sample position (xCb, yCb) of the current coding block, wherein the acquisition unit (1001) is further configured to acquire second indication information regarding the position (cbWidth / 2, cbHeight / 2) of the luma of the current coding block when the first indication information indicates that the MIP is not applied to the luma sample at the position (cbWidth / 2, cbHeight / 2) of the luma with reference to the top-left luma sample position (xCb, yCb) of the current coding block, wherein the setting unit (1002) is further configured to set the value of the intra prediction mode of the luma related to the current coding block to a second default value when the second indication information indicates that the intra block copy (IBC) mode or the palette mode is applied to the luma sample at the position (cbWidth / 2, cbHeight / 2) of the luma with reference to the top-left luma sample position (xCb, yCb) of the current coding block, wherein the device further includes a chroma intra prediction mode unit (1003) configured to acquire the value of the chroma intra prediction mode based on the value of the intra prediction mode of the luma of the current coding block. **Claim 17** wherein the first indication information is intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2], The device according to claim 16, wherein when intra_mip_flag[xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to 1, the first indication information indicates that the MIP is applied to the luma sample. **Claim 18** The second instruction information is CuPredMode[0][xCb + cbWidth / 2][yCb + cbHeight / 2], The device according to claim 16 or 17, wherein when CuPredMode[0][xCb + cbWidth / 2][yCb + cbHeight / 2] is equal to MODE_IBC or MODE_PLT, the second instruction information indicates that the IBC mode or the palette mode is applied to the luma sample.

19. The device according to any one of claims 16 to 18, wherein the first default value is a value in the planar mode and the second default value is a value in the DC mode.

20. The device according to any one of claims 16 to 19, which is a decoder.

21. The device according to any one of claims 16 to 19, which is an encoder.

Images