Video decoding and encoding method, computing system, and computer program product

Abstract

Various implementations described herein include methods and systems for video encoding and decoding. In one aspect, a video decoding method includes receiving video data including a first block from a video bitstream. The method also includes obtaining a set of partition modes and generating a reference template for the first block. The method further includes identifying an index of a set of reordered partition modes from the video bitstream and reconstructing the first block using a first partition mode of the set of reordered partition modes, the first partition mode corresponding to the index.

Description

[Technical Field]

[0001] The disclosed embodiments relate generally to video coding, including, but not limited to, systems and methods for reordering partition-based prediction modes. [Background technology]

[0002] Digital video is supported by a variety of electronic devices, such as digital televisions, laptop or desktop computers, tablet computers, digital cameras, digital recording devices, digital media players, video game consoles, smartphones, video teleconferencing devices, video streaming devices, etc. The electronic devices transmit, receive, or otherwise communicate digital video data over communication networks and / or store the digital video data in storage devices. Due to the limited bandwidth capabilities of communication networks and the limited memory resources of storage devices, video coding may be used to compress the video data according to one or more video coding standards before the video data is communicated or stored.

[0003] Several video codec standards have been developed. For example, video coding standards include AOMedia Video 1 (AV1), Versatile Video Coding (VVC), Joint Exploration test Model (JEM), High-Efficiency Video Coding (HEVC / H.265), Advanced Video Coding (AVC / H.264), and Moving Picture Expert Group (MPEG) coding. Video coding generally uses prediction methods (e.g., inter-prediction, intra-prediction, etc.) that exploit the redundancy inherent in video data. The goal of video coding is to compress video data into a format that uses a lower bitrate while avoiding or minimizing degradation of video quality.

[0004] HEVC, also known as H.265, is a video compression standard designed as part of the MPEG-H project. ITU-T and ISO / IEC published HEVC / H.265 in 2013 (Version 1), 2014 (Version 2), 2015 (Version 3), and 2016 (Version 4). Versatile Video Coding (VVC), also known as H.266, is a video compression standard intended as the successor to HEVC. ITU-T and ISO / IEC published the VVC / H.266 standard in 2020 (Version 1) and 2022 (Version 2). AV1 is an open video coding format designed as a replacement for HEVC. The effective version 1.0.0, including errata 1, of the specification was released on January 8, 2019. Summary of the Invention

[0005] As described in detail below, some systems support up to 68 partition (wedge) modes for encoding / decoding video blocks. For example, a partition mode may consist of 20 angles and four offsets per angle (e.g., duplicate cases are removed). In a video bitstream, the angle direction (whether the angle is greater or less than 180 degrees), the angle index, and the offset index may be signaled separately with three syntax elements. However, because the frequencies of each partition mode are not the same, a fixed order of mode signaling is not optimal. This disclosure describes methods and systems for reordering partition modes based on available information (e.g., reference blocks and reference templates). Reordering partition modes can reduce bandwidth (e.g., fewer bits are used to signal higher-frequency modes) and / or improve decoding efficiency.

[0006] According to some embodiments, a method of video decoding is provided, the method including: (i) receiving video data from a video bitstream, the video data including a plurality of blocks including a first block; (ii) obtaining a set of partition modes; (iii) generating a reference template for the first block; (iv) reordering the set of partition modes based on the reference template; (v) identifying an index of the reordered set of partition modes from the video bitstream; and (vi) reconstructing the first block using a first partition mode of the reordered set of partition modes, the first partition mode corresponding to the index.

[0007] According to some embodiments, a method of video encoding is provided, the method including: (i) receiving video data including a plurality of blocks including a first block; (ii) obtaining a set of partition modes; (iii) generating a reference template for the first block; (iv) reordering the set of partition modes based on the reference template; (v) determining an index of the first partition mode in the reordered set of partition modes; (vi) encoding the first block using the first partition mode; and (vii) transmitting the index via a video bitstream.

[0008] According to some embodiments, a computing system, such as a streaming system, a server system, a personal computer system, or other electronic device, is provided. The computing system includes control circuitry and a memory that stores one or more sets of instructions. The one or more sets of instructions include instructions for performing any of the methods described herein. In some embodiments, the computing system includes an encoder component and a decoder component (e.g., a transcoder component).

[0009] According to some embodiments, a non-transitory computer-readable storage medium is provided that stores one or more sets of instructions for execution by a computing system, the one or more sets of instructions including instructions for performing any of the methods described herein.

[0010] Thus, devices and systems are disclosed, along with methods for video encoding and decoding. Such methods, devices, and systems may supplement or replace conventional methods, devices, and systems for video encoding / decoding. The features and advantages described herein are not necessarily all-inclusive; in particular, some additional features and advantages will be apparent to those skilled in the art in view of the drawings, specification, and claims provided in this disclosure. Furthermore, it should be noted that the language used herein has been chosen primarily for ease of reading and educational purposes, and not necessarily to define or limit the subject matter described herein.

[0011] In order that the present disclosure may be understood in more detail, a more particular description may be made with reference to the features of various embodiments, some of which are illustrated in the accompanying drawings, which should not be considered necessarily limiting, as they merely illustrate relevant features of the present disclosure, and other useful features may be recognized for illustrative purposes, as those skilled in the art will understand upon reading the present disclosure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram illustrating an exemplary communication system according to some embodiments. [Figure 2A] FIG. 2 is a block diagram depicting exemplary elements of an encoder component in accordance with some embodiments. [Figure 2B] FIG. 2 is a block diagram depicting exemplary elements of a decoder component according to some embodiments. [Figure 3]FIG. 1 is a block diagram illustrating an exemplary server system according to some embodiments. [Figure 4A] 1 illustrates an exemplary coding tree structure according to some embodiments. [Figure 4B] 1 illustrates an exemplary coding tree structure according to some embodiments. [Figure 4C] 1 illustrates an exemplary coding tree structure according to some embodiments. [Figure 4D] 1 illustrates an exemplary coding tree structure according to some embodiments. [Figure 5A] 1 illustrates an example of a partition-based prediction mode according to some embodiments. [Figure 5B] 1 illustrates an exemplary partitioning mode mixture according to some embodiments. [Figure 5C] 1 illustrates an exemplary partitioning mode mixture according to some embodiments. [Figure 5D] 1 illustrates an exemplary wedge-based partitioning according to some embodiments. [Figure 5E] 10 illustrates exemplary inter-intra mask weights according to some embodiments. [Figure 6A] FIG. 1 is a flow diagram illustrating an example video encoding method according to some embodiments. [Figure 6B] FIG. 1 is a flow diagram illustrating an example video decoding method according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0013] According to common practice, the various features illustrated in the drawings are not necessarily drawn to scale, and the same reference numerals may be used to denote like features throughout the specification and drawings.

[0014] This disclosure describes, among other things, various partitioning techniques for partitioning video blocks for more optimal motion prediction and higher-quality encoding. This disclosure also describes generating a reordered partition mode list by reordering partition modes (e.g., wedge partition modes) based on available decoder-side information. An index having a maximum value N may be parsed to indicate the position of the best partition mode within the reordered partition mode list. The index may be coded using multi-symbol entropy coding, and the maximum index value may be predefined or signaled in a high-level syntax. Reordering the partition modes in this manner may improve decoding efficiency.

[0015] [Example Systems and Devices] 1 is a block diagram illustrating a communication system 100 according to some embodiments. Communication system 100 includes a source device 102 and multiple electronic devices 120 (e.g., electronic devices 120-1 through 120-m) that are communicatively coupled to each other via one or more networks. In some embodiments, communication system 100 is a streaming system used by video-enabled applications, such as, for example, video conferencing applications, digital TV applications, and media storage and / or distribution applications.

[0016] Source device 102 includes a video source 104 (e.g., a camera component or media storage) and an encoder component 106. In some embodiments, video source 104 is a digital camera (e.g., configured to generate an uncompressed video sample stream). Encoder component 106 generates one or more encoded video bitstreams from the video stream. The video stream from video source 104 has a higher data volume than encoded video bitstream 108 generated by encoder component 106. Because encoded video bitstream 108 has a lower data volume (less data) than the video stream from the video source, encoded video bitstream 108 requires less bandwidth for transmission and less storage space for storage than the video stream from video source 104. In some embodiments, source device 102 does not include encoder component 106 (e.g., configured to transmit uncompressed video over network 110).

[0017] The one or more networks 110 represent any number of networks that carry information between the source device 102, the server system 112, and / or the electronic device 120, including, for example, wireline and / or wireless communication networks. The one or more networks 110 may exchange data over circuit-switched and / or packet-switched channels. Exemplary networks include telecommunications networks, local area networks, wide area networks, and / or the Internet.

[0018] One or more networks 110 include a server system (e.g., a distributed / cloud computing system). In some embodiments, server system 112 is or includes a streaming server (e.g., configured to store and / or distribute video content, such as an encoded video stream from source device 102). Server system 112 includes a coder component 114 (e.g., configured to encode and / or decode video data). In some embodiments, coder component 114 includes an encoder component and / or a decoder component. In various embodiments, coder component 114 is instantiated as hardware, software, or a combination thereof. In some embodiments, coder component 114 is configured to decode encoded video bitstream 108 and re-encode the video data using a different encoding standard and / or methodology to generate encoded video data 116. In some embodiments, server system 112 is configured to generate multiple video formats and / or encodings from encoded video bitstream 108. In some embodiments, server system 112 functions as a Media-Aware Network Element (MANE). For example, server system 112 may be configured to prune encoded video bitstream 108 to tailor potentially different bitstreams to one or more electronic devices 120. In some embodiments, the MANE is separate from server system 112.

[0019] Electronic device 120-1 includes a decoder component 122 and a display 124. In some embodiments, decoder component 122 is configured to decode encoded video data 116 to generate an outgoing video stream that can be rendered on a display or other type of rendering device. In some embodiments, one or more electronic devices 120 do not include a display component (e.g., are communicatively coupled to an external display device and / or include a media stream). In some embodiments, electronic device 120 is a streaming client. In some embodiments, electronic device 120 is configured to access server system 112 to obtain encoded video data 116.

[0020] The source device 102 and / or the electronic devices 120 are sometimes referred to as “terminal devices” or “user devices.” In some embodiments, the source device 102 and / or one or more of the electronic devices 120 are instances of a server system, a personal computer, a portable device (e.g., a smartphone, tablet, or laptop), a wearable device, a videoconferencing device, and / or other types of electronic devices.

[0021] In an example of operation of communication system 100, source device 102 sends encoded video bitstream 108 to server system 112. For example, source device 102 may code a stream of pictures captured by the source device. Server system 112 may receive encoded video bitstream 108 and decode and / or encode encoded video bitstream 108 with coder component 114. For example, server system 112 may apply coding to the video data that is more optimal for network transmission and / or storage. Server system 112 may transmit encoded video data 116 (e.g., one or more coded video bitstreams) to one or more electronic devices 120. Each electronic device 120 may decode the encoded video data 116 and, optionally, display the video pictures.

[0022] 2A is a block diagram illustrating exemplary elements of encoder component 106 according to some embodiments. Encoder component 106 receives a source video sequence from video source 104. In some embodiments, encoder component 106 includes a receiver (e.g., transceiver) component configured to receive the source video sequence. In some embodiments, encoder component 106 receives a video sequence from a remote video source (e.g., a video source that is a component of a different device than encoder component 106). Video source 104 may provide the source video sequence in the form of a digital video sample stream that can be of any suitable bit depth (e.g., 8-bit, 10-bit, or 12-bit), any color space (e.g., BT.601 YCrCb, or RGB), and any suitable sampling structure (e.g., YCrCb 4:2:0 or YCrCb 4:4:4). In some embodiments, video source 104 is a storage device that stores previously captured / prepared video. In some embodiments, video source 104 is a camera that captures local image information as a video sequence. Video data may be provided as multiple individual pictures that, when viewed in sequence, impart motion. The pictures themselves may be organized as a spatial array of pixels, each of which may contain one or more samples, depending on the sampling structure, color space, etc., used. Those skilled in the art will readily understand the relationship between pixels and samples. The following discussion focuses on samples.

[0023] The encoder component 106 is configured to code and / or compress pictures of a source video sequence into a coded video sequence 216 in real time or under other time constraints required by the application. Imposing an appropriate coding rate is one function of the controller 204. In some embodiments, the controller 204 controls and is operatively coupled to other functional units, which are described below. Parameters set by the controller 204 may include rate control-related parameters (e.g., picture skip, quantizer, and / or lambda value for rate-distortion optimization techniques), picture size, group-of-picture (GOP) layout, maximum motion vector search range, etc. Those skilled in the art can readily identify other functions of the controller 204, as they may be relevant to the encoder component 106 being optimized for a particular system design.

[0024] In some embodiments, the encoder component 106 is configured to operate in a coding loop. In a simplified example, the coding loop includes a source coder 202 (e.g., responsible for generating symbols, such as a symbol stream, based on an input picture to be coded and a reference picture) and a (local) decoder 210. The decoder 210 reconstructs the symbols to generate sample data similar to the (remote) decoder (if the compression between the symbols and the coded video bitstream is lossless). The reconstructed sample stream (sample data) is input to the reference picture memory 208. Because decoding the symbol stream yields bit-exact results independent of the location of the decoder (local or remote), the contents in the reference picture memory 208 are also bit-perfect between the local and remote encoders. In this way, the predictive portion of the encoder interprets the same sample values ​​as reference picture samples that the decoder would interpret when using prediction during decoding. This basic principle of reference picture synchronicity (and the resulting drift when synchronicity cannot be maintained, for example due to channel errors) is known.

[0025] The operation of decoder 210 can be the same as that of a remote decoder, such as decoder component 122, described in detail below in connection with Figure 2B. Referring briefly to Figure 2B, however, the entropy decoding portion of decoder component 122, including buffer 252 and parser 254, may not be fully implemented in local decoder 210, given that symbols are available and symbol encoding / decoding for the coded video sequence by entropy coder 214 and parser 254 can be lossless.

[0026] The decoder techniques described herein may exist in substantially the same functional form in the corresponding encoder, with the exception of parsing / entropy decoding. For this reason, the disclosed subject matter focuses on the operation of the decoder. Descriptions of the encoder techniques may be omitted, as they are the inverse of the decoder techniques.

[0027] As part of its operation, source coder 202 may perform motion-compensated predictive coding, which predictively codes an input frame with reference to one or more previously coded frames from the video sequence designated as reference frames. In this manner, coding engine 212 codes differences between pixel blocks of the input frame and pixel blocks of reference frames that may be selected as prediction references for the input frame. Controller 204 may manage the coding operations of source coder 202, including, for example, setting parameters and subgroup parameters used to encode the video data.

[0028] The decoder 210 decodes the coded video data of frames that may be designated as reference frames based on symbols generated by the source coder 202. The operation of the coding engine 212 may advantageously be a lossy process. When the coded video data is decoded by a video decoder (not shown in FIG. 2A ), the reconstructed video sequence is a copy of the source video sequence, with some errors. The decoder 210 may replicate the decoding process that may be performed by a remote video decoder on the reference frames, causing the reconstructed reference frames to be stored in the reference picture memory 208. In this way, the encoder component 106 locally stores copies of reconstructed reference frames that have content in common with the reconstructed reference frames that would be obtained by the remote video decoder (without transmission errors).

[0029] The predictor 206 may perform a predictive search for the coding engine 212. That is, for a new picture to be coded, the predictor 206 may search the reference picture memory 208 for specific metadata, such as reference picture motion vectors, block shapes, or sample data (as candidate reference pixel blocks) that can be suitable prediction references for the new picture. The predictor 206 may operate on a sample block-by-pixel block basis to find suitable prediction references. As determined by the search results obtained by the predictor 206, the input picture may have prediction references drawn from multiple reference pictures stored in the reference picture memory 208.

[0030] The output of all the above functional units may undergo entropy coding in entropy coder 214. Entropy coder 214 converts the symbols produced by the various functional units into a coded video sequence by losslessly compressing the symbols according to techniques known to those skilled in the art (e.g., Huffman coding, variable length coding, and / or arithmetic coding).

[0031] In some embodiments, the output of the entropy coder 214 is coupled to a transmitter. The transmitter may be configured to buffer coded video sequences generated by the entropy coder 214 and prepare them for transmission over a communication channel 218, which may be a hardware / software link to a storage device that stores the coded video data. The transmitter may be configured to merge the coded video data from the source coder 202 with other data to be transmitted, such as coded audio data and / or auxiliary data streams (sources not shown). In some embodiments, the transmitter may transmit additional data along with the coded video. The source coder 202 may include such data as part of the coded video sequence. The additional data may include other forms of redundant data, such as temporal / spatial / SNR enhancement layers, redundant pictures and slices, Supplementary Enhancement Information (SEI) messages, Visual Usability Information (VUI) parameter set fragments, etc.

[0032] The controller 204 may manage the operation of the encoder component 106. During coding, the controller 204 may assign a specific coding picture type to each coded picture, which may affect the coding technique applied to each picture. For example, a picture may be assigned as an intra picture (I picture), a predicted picture (P picture), or a bidirectionally predicted picture (B picture). An intra picture can be encoded and decoded without using any other picture in the sequence as a source of prediction. Some video codecs allow various types of intra pictures, including, for example, Independent Decoder Refresh (IDR) pictures. Those skilled in the art will be aware of such variations of I pictures and their respective applications and characteristics, so they will not be repeated here. A predictive picture can be encoded and decoded by intra prediction or inter prediction using at most one motion vector and reference index to predict the sample values ​​of each block. Bidirectionally predictive pictures can be coded and decoded using intra- or inter-prediction, which uses at most two motion vectors and reference indices to predict the sample values ​​of each block. Similarly, multiple-predictive pictures can use more than two reference pictures and associated metadata for the reconstruction of a single block.

[0033] A source picture may be spatially subdivided into multiple sample blocks (e.g., blocks of 4x4, 8x8, 4x8, or 16x16 samples, respectively) and coded block by block. Blocks may be predictively coded with reference to other (already coded) blocks as determined by the coding assignment applied to each picture of the block. For example, blocks of an I-picture may be coded non-predictively, or they may be predictively coded with reference to already coded blocks of the same picture (spatial prediction or intra-prediction). Pixel blocks of a P-picture may be coded non-predictively, or with spatial prediction or temporal prediction with reference to one previously coded reference picture. Blocks of a B-picture may be coded non-predictively, or with spatial prediction or temporal prediction with reference to one or two previously coded reference pictures.

[0034] Video may be captured as multiple source pictures (video pictures) in a time sequence. Intra-picture prediction (often abbreviated as intra-prediction) exploits spatial correlation within a given picture, while inter-picture prediction exploits correlation (temporal or otherwise) between pictures. As an example, a particular picture being encoded / decoded, called the current picture, is partitioned into blocks. When a block in the current picture resembles a reference block in a previously coded and still buffered reference picture in the video, that block in the current picture may be coded by a vector called a motion vector. The motion vector points to a reference block within the reference picture and may have a third dimension that identifies the reference picture if multiple reference pictures are used.

[0035] Encoder component 106 may perform coding operations in accordance with a given video coding technique or standard, such as any described herein. In doing so, encoder component 106 may perform various compression operations, including predictive coding operations that exploit temporal and spatial redundancies in the input video sequence. Thus, the coded video data may conform to a syntax specified by the video coding technique or standard being used.

[0036] 2B is a block diagram depicting exemplary elements of a decoder component 122 according to some embodiments. The decoder component 122 of FIG. 2B is coupled to a channel 218 and a display 124. In some embodiments, the decoder component 122 includes a transmitter coupled to a loop filter unit 256 and configured to transmit data to the display 124 (e.g., via a wired or wireless connection).

[0037] In some embodiments, decoder component 122 includes a receiver coupled to a channel and configured to receive data from the channel (e.g., via a wired or wireless connection). The receiver may be configured to receive one or more coded video sequences to be decoded by decoder component 122. In some embodiments, the decoding of each coded video sequence is independent of the other coded video sequences. Each coded video sequence may be received from channel 218, which may be a hardware / software link to a storage device storing the coded video data. The receiver may receive the coded video data along with other data, such as coded audio data and / or auxiliary data streams, which may be forwarded to their respective using entities (not shown). The receiver may separate the coded video sequence from the other data. In some embodiments, the receiver receives additional (redundant) data along with the coded video. The additional data may be included as part of the coded video sequence. The additional data may be used by decoder component 122 to decode the data and / or to more accurately reconstruct the original video data. The additional data can be in the form of, for example, temporal / spatial / SNR enhancement layers, redundant slices, redundant pictures, forward error correction codes, etc.

[0038] According to some embodiments, the decoder component 122 includes a buffer memory 252, a parser 254 (sometimes referred to as an entropy decoder), a scaler / inverse transform unit 258, an intra-picture prediction unit 262, a motion compensated prediction unit 260, an aggregator 268, a loop filter unit 256, a reference picture memory 266, and a current picture memory 264. In some embodiments, the decoder component 122 is implemented as one or more integrated circuits and / or other electronic circuits. In some embodiments, the decoder component 122 is implemented at least partially in software.

[0039] Buffer memory 252 is coupled between channel 218 and parser 254 (e.g., to combat network jitter). In some embodiments, buffer memory 252 is separate from decoder component 122. In some embodiments, a separate buffer memory is provided between the output of channel 218 and decoder component 122. In some embodiments, a separate buffer memory is provided outside decoder component 122 (e.g., to combat network jitter) in addition to buffer memory 252 within decoder component 122 (e.g., configured to handle playback timing). When receiving data from a storage / forwarding device with sufficient bandwidth and controllability or from an isosynchronous network, buffer memory 252 may not be required or may be small. For use with best-effort packet networks such as the Internet, buffer memory 252 may be required, but may be relatively large and advantageously adaptively sized, and may be implemented at least in part in an operating system or similar element (not shown) outside decoder component 122.

[0040] Parser 254 is configured to reconstruct symbols 270 from the coded video sequence. The symbols may include, for example, information used to manage the operation of decoder component 122 and / or information for controlling a rendering device such as display 124. Control information for the rendering device may take the form of an SEI message or a VUI parameter set fragment (not shown). Parser 254 parses (entropy decodes) the coded video sequence. The coding of the coded video sequence may follow a video coding technique or standard and may follow principles well known to those skilled in the art, including variable length coding, Huffman coding, context-sensitive or non-context-sensitive arithmetic coding, etc. Parser 254 may extract from the coded video sequence a set of subgroup parameters for at least one of the subgroups of pixels in the video decoder based on at least one parameter corresponding to the group. The subgroup may include a group of pictures (GOP), a picture, a tile, a slice, a macroblock, a coding unit (CU), a block, a transform unit (TU), a prediction unit (PU), etc. Parser 254 may also extract information from the coded video sequence, such as transform coefficients, quantization parameter values, motion vectors, and the like.

[0041] The reconstruction of symbols 270 can have many different units depending on the type of coded video picture or portion thereof (e.g., inter and intra pictures, inter and intra blocks) and other factors. Which units are included and how may be controlled by subgroup control information parsed by parser 254 from the coded video sequence. The flow of such subgroup control information between parser 254 and the following units is not shown for clarity.

[0042] The decoder component 122 may be conceptually subdivided into a number of functional units, and in some implementations many of these units may interact closely with and be at least partially integrated with one another, but for clarity, the conceptual subdivision of functional units is retained here.

[0043] The scaler / inverse transform unit 258 receives quantized transform coefficients as symbols 270 from the parser 254, along with control information (e.g., which transform to use, block size, quantization coefficients, and / or quantization scaling matrix). The scaler / inverse transform unit 258 may output blocks containing sample values ​​that can be input to the aggregator 268. In some cases, the output samples of the scaler / inverse transform unit 258 relate to intra-coded blocks, i.e., blocks that do not use prediction information from a previously reconstructed picture but can use prediction information from a previously reconstructed portion of the current picture. Such prediction information may be provided by the intra-picture prediction unit 262. The intra-picture prediction unit 262 may generate blocks of the same size and shape as the block being reconstructed using surrounding already reconstructed information fetched from the current (partially reconstructed) picture from the current picture memory 264. The aggregator 268 may add, on a sample-by-sample basis, the prediction information generated by the intra-picture prediction unit 262 to the output sample information provided by the scaler / inverse transform unit 258.

[0044] In other cases, the output samples of the scalar / inverse transform unit 258 relate to an inter-coded and potentially motion-compensated block. In such cases, the motion-compensated prediction unit 260 can access the reference picture memory 266 to fetch samples used for prediction. After motion-compensating the fetched samples according to symbols 270 related to the block, these samples can be added by an aggregator 268 to the output of the scalar / inverse transform unit 258 (in this case, referred to as residual samples or a residual signal) to generate output sample information. The addresses in the reference picture memory 266 from which the motion-compensated prediction unit 260 fetches the prediction samples can be controlled by motion vectors. The motion vectors can be available to the motion-compensated prediction unit 260 in the form of symbols 270, which can have, for example, X, Y, and reference picture components. Motion compensation can also include interpolation of sample values ​​fetched from the reference picture memory 266 when sub-sample accurate motion vectors are used, motion vector prediction mechanisms, and the like.

[0045] The output samples of aggregator 268 may be subjected to various loop filtering techniques in loop filter unit 256. Video compression techniques may include in-loop filter techniques that are controlled by parameters contained in the coded video bitstream and made available to loop filter unit 256 as symbols 270 from parser 254, but may also be responsive to meta-information obtained during decoding of previous portions (in decoding order) of the coded picture or coded video sequence, or even to previously reconstructed loop-filtered sample values.

[0046] The output of the loop filter unit 256 can be a sample stream that can be output to a render device such as the display 124 and further stored in the reference picture memory 266 for use in future inter-picture prediction.

[0047] A particular coded picture, once reconstructed, may be used as a reference picture for future prediction. Once a coded picture is reconstructed and the coded picture is identified as a reference picture (e.g., by parser 254), the current reference picture may become part of reference picture memory 266, and any unused current picture memory may be reallocated before beginning reconstruction of a subsequent coded picture.

[0048] Decoder component 122 may perform decoding operations according to a given video compression technology, which may be documented in a standard, such as any of the standards described herein. A coded video sequence may conform to the syntax prescribed by the video compression technology or standard in use, in the sense that it follows the syntax of the video compression technology or standard as specified in the video compression technology document or standard, specifically in a profile document therein. Also, for compliance with some video compression technologies or standards, the complexity of a coded video sequence may be within boundaries defined by a level of the video compression technology or standard. In some cases, the level limits the maximum picture size, maximum frame rate, maximum reconstruction sample rate (e.g., measured in megasamples per second), maximum reference picture size, etc. The limits set by the level may, in some cases, be further constrained through a Hypothetical Reference Decoder (HRD) specification and metadata for HRD buffer management signaled in the coded video sequence.

[0049] 3 is a block diagram illustrating a server system 112 according to some embodiments. The server system 112 includes a control circuit 302, one or more network interfaces 304, a memory 314, a user interface 306, and one or more communication buses 312 interconnecting these components. In some embodiments, the control circuit 302 includes one or more processors (e.g., a CPU, a GPU, and / or a DPU). In some embodiments, the control circuit 302 includes one or more field programmable gate arrays (FPGAs), hardware accelerators, and / or one or more integrated circuits (e.g., application specific integrated circuits).

[0050] The network interface 304 may be configured to interface with one or more communications networks (e.g., wireless, wired, and / or optical networks). Communications networks may be local, wide-area, metropolitan, vehicular, and industrial, real-time, delay-tolerant, and the like. Examples of communications networks include local area networks such as Ethernet and wireless LAN; cellular networks including GSM, 3G, 4G, 5G, LTE, and the like; TV wired or wireless wide-area digital networks including cable TV, satellite TV, and terrestrial TV; and vehicular and industrial networks including CANBus. Such communications may be one-way receive-only (e.g., broadcast TV), one-way transmit-only (e.g., CANBus to a specific CANBus device), or bidirectional (e.g., to another computer system using a local or wide-area digital network). Such communications may include communications to one or more cloud computing networks.

[0051] The user interface 306 includes one or more output devices 308 and / or one or more input devices 310. The input devices 310 may include one or more of a keyboard, a mouse, a trackpad, a touchscreen, a dataglove, a joystick, a microphone, a scanner, a camera, etc. The output devices 308 may include one or more of an audio output device (e.g., a speaker), a visual output device (e.g., a display or monitor), etc.

[0052] Memory 314 may include high-speed random-access memory (e.g., DRAM, SRAM, DDR RAM, and / or other random-access solid-state memory devices) and / or non-volatile memory (e.g., one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, and / or other non-volatile solid-state storage devices). Memory 314 optionally includes one or more storage devices that are remote from control circuitry 302. Memory 314, or alternatively, a non-volatile solid-state memory device within memory 314, comprises a non-transitory computer-readable storage medium. In some embodiments, memory 314, or the non-transitory computer-readable storage medium of memory 314, stores the following programs, modules, instructions, and data structures, or a subset or superset thereof: • an operating system 316 that contains procedures for handling various basic system services and for performing hardware-dependent tasks; • a network communications module 318 used to connect the server system 112 to other computing devices via one or more network interfaces 304 (e.g., via wired and / or wireless connections); A coding module 320 that performs various functions related to encoding and / or decoding data, such as video data. In some embodiments, the coding module 320 is an instance of the coder component 114. The coding module 320: a decoding module 322 that performs various functions related to decoding the encoded data, such as the functions described above with respect to the decoder component 122; and an encoding module 340 that performs various functions related to encoding data, such as the functions described above with respect to the encoder component 106; A picture memory 352 that stores pictures and picture data, e.g., for use by coding module 320. In some embodiments, picture memory 352 includes one or more of reference picture memory 208, buffer memory 252, current picture memory 264, and reference picture memory 266.

[0053] In some embodiments, the decoding module 322 includes a parsing module 324 (e.g., configured to perform various functions described above with respect to the parser 254), a transform module 326 (e.g., configured to perform various functions described above with respect to the scanner / inverse transform unit 258), a prediction module 328 (e.g., configured to perform various functions described above with respect to the motion compensated prediction unit 260 and / or the intra-picture prediction unit 262), and a filter module 330 (e.g., configured to perform various functions described above with respect to the loop filter 256).

[0054] In some embodiments, encoding module 340 includes a code module 342 (e.g., configured to perform various functions described above with respect to source coder 202 and / or coding engine 212) and a prediction module 344 (e.g., configured to perform various functions described above with respect to predictor 206). In some embodiments, decoding module 322 and / or encoding module 340 include a subset of the modules shown in Figure 3. For example, a shared prediction module is used by both decoding module 322 and encoding module 340.

[0055] Each of the above-described modules stored in memory 314 corresponds to a set of instructions for performing functions described herein. The above-described modules (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules; thus, various subsets of these modules may be combined or otherwise rearranged in various embodiments. For example, coding module 320 optionally does not include separate decoding and encoding modules, but rather uses the same set of modules that perform both sets of functions. In some embodiments, memory 314 stores a subset of the modules and data structures described above. In some embodiments, memory 314 stores additional modules and data structures not described above, such as an audio processing module.

[0056] While FIG. 3 illustrates a server system 112 according to some embodiments, FIG. 3 is intended as a functional illustration of various features that may be present in one or more server systems, rather than an architectural diagram of the embodiments described herein. Indeed, as will be recognized by those skilled in the art, items shown separately may be combined and some items may be separated. For example, some items shown separately in FIG. 3 may be implemented on a single server, and single items may be implemented by one or more servers. The actual number of servers used to implement server system 112 and how features are allocated among them may vary from implementation to implementation and, optionally, depend in part on the amount of data traffic the server system handles during peak and average usage periods.

[0057] [Example coding processes and techniques] The coding processes and techniques described below may be implemented in the devices and systems described above (e.g., source device 102, server system 112, and / or electronic device 120). FIGS. 4A-4D illustrate example coding tree structures according to some embodiments. As shown in the first coding tree structure (400) of FIG. 4A, some coding approaches (e.g., VP9) use four-way partition trees, from a 64x64 level down to a 4x4 level, with some additional restrictions for 8x8 blocks. In FIG. 4A, the partition designated as R is recursive in that the same partition tree is repeated at smaller scales until the lowest 4x4 level is reached.

[0058] As shown in the second coding tree structure (402) of Figure 4B, some coding approaches (e.g., AV1) extend the partition tree to a 10-way structure and increase the maximum size (called a superblock in VP9 / AV1) to start at 128x128. The second coding tree structure includes 4:1 / 1:4 rectangular partitions that are not included in the first coding tree structure. The partition type shown in the second row of Figure 4B, which includes three subpartitions, is called a T-type partition. In addition to the coding block size, a coding tree depth is defined to indicate the partition depth from the root node.

[0059] For example, a CTU may be divided into CUs by using a quadtree structure represented as a coding tree to adapt to various local characteristics, as seen in HEVC, etc. In some embodiments, a decision as to 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 a PU partition type. Within one PU, the same prediction process is applied, and related information is sent to the decoder on a PU-by-PU basis. After obtaining residual blocks by applying a prediction process based on the PU partition type, the CU may be partitioned into TUs according to another quadtree structure, such as the coding tree of the CU.

[0060] A quaternary tree, including nested multitype trees using binary and ternary segmentation structures, such as those found in VVC, can replace the concept of multiple partition unit types. For example, it eliminates the separation of the concepts of CU, PU, ​​and TU, except when necessary for CUs whose size is too large for the maximum transform length, increasing the flexibility of CU partition shapes. In the coding tree structure, CUs can have either square or rectangular shapes. CTUs are initially partitioned using a quaternary tree (or quad-tree) structure. The quaternary tree leaf nodes can be further partitioned using a multitype tree structure. As shown in the third coding tree structure (404) in FIG. 4C, the multitype tree structure includes four partition types. The multitype tree leaf nodes are called CUs, and unless the CUs are too large for the maximum transform length, this segmentation is used for prediction and transform processing without further partitioning. This means that in most cases, CUs, PUs, and TUs have the same block size in a quaternary tree with a nested multitype tree coding block structure. An example of block partitioning for one CTU (406) is shown in FIG. 4D, which depicts an example of a quadtree with a nested multi-type tree coding block structure.

[0061] Motion estimation involves determining motion vectors that describe the transformation from one image (picture) to another. Reference images (or blocks) can be from adjacent frames in a video sequence. Motion vectors can relate to the entire image (global motion estimation) or to specific blocks. Furthermore, motion vectors can correspond to translational or warping models that approximate motion (e.g., rotation and translation in three dimensions, and zoom). Motion estimation can be improved in some environments (e.g., involving more complex video objects) by further partitioning the blocks.

[0062] Geometric partitioning mode (GPM) can focus on inter-picture predicted blocks (e.g., CUs). When GPM is applied to a block, the block is divided into two parts by a linear partitioning boundary. Unlike regular inter prediction, which is performed on rectangular blocks, GPM divides the coding block into two regions by 64 predefined lines, generates inter-predicted samples for each region, and then blends them to obtain the final inter-predicted sample. The location of the partitioning boundary can be mathematically defined by an angle parameter φ and an offset parameter ρ. These parameters can be quantized and compiled into a GPM partitioning index lookup table. The GPM partitioning index of the current block can be coded into the bitstream. For example, for a CU with size w × h = 2k × 2l (in terms of luma samples), where k, l ∈ {3...6}, 64 partition modes are supported by GPM in VVC. GPM may be ineffective for CUs with aspect ratios greater than 4:1 or smaller than 1:4, for example, because narrow CUs rarely contain geometrically separated patterns.

[0063] After partitioning, two GPM sections (partitions) contain individual motion information that can be used to predict the corresponding section in the current block. In some embodiments, only unidirectional motion compensated prediction (MCP) is allowed for each section of the GPM, thereby making the required memory bandwidth for the GPM's MCP equal to that of a regular bidirectional MCP. To simplify the coding of motion information and reduce the possible combinations of the GPM, the motion information can be coded in merge mode. The GPM merge candidate list can be derived from a conventional merge candidate list to ensure that only unidirectional motion information is included.

[0064] 5A illustrates a prediction process of a GPM according to some embodiments. A current block 510 is partitioned into a right section and a left section by a partition 516. The right predicted portion of the current block 510 (e.g., a CU) of a current picture 502 (having a size of w×h) is predicted by MV0 from a reference block of a reference picture 504, while the left portion is predicted by MV1 from a reference block 514 of a reference picture 506.

[0065] In some embodiments, when a current block is divided into two partitions by a partition (e.g., partition 516), blending (e.g., corresponding to a "blending mode" or "masked blending") is applied to combine the two partitioned blocks. Figure 5B illustrates an example blending matrix for a partition (e.g., partition 516) according to some embodiments. In this example, the final GPM prediction (PG) is generated by performing a blending process using integer blending matrices W0 and W1, each of which includes weights in the value range of 0 to 8. This can be expressed as follows:

number

[0066] The generated GPM prediction (PG) can then be subtracted from the original signal to generate a residual. The residual can be transformed, quantized, and coded into a bitstream, for example, using a conventional VVC transform, quantization, and entropy coding engine. At the decoder side, the signal is reconstructed by adding the residual to the GPM prediction PG. For example, if the residual is negligible, skip mode can also be supported by the GPU. For example, the residual can be dropped at the encoder, and the GPM prediction PG can be directly used by the decoder as the reconstructed signal.

[0067] GPM can be further enhanced by, for example, GPM+TM (Bilateral Matching), GPM+MMVD (Merge mode with Motion Vector Difference), and Inter+Intra GPM. As shown in Figure 5C, the blending strength or blending area width θ can be fixed for all different content. In some embodiments, the weight values ​​of the blending mask are given by a ramp function:

number

number

[0068] Such a design may not always be optimal, because a fixed blending area width may not always provide the best blending quality for various types of video content. For example, video content usually contains strong textures and sharp edges, which requires a narrow blending area to preserve edge information. For content captured by a camera, blending is generally necessary, but the blending area width may depend on many factors, such as the actual boundaries of moving objects and the uniqueness of the movements of the two partitions.

[0069] To solve this problem, an adaptive blending scheme can be used in the GPM that dynamically adjusts the width of the blending area surrounding the GPM partition boundary. For example, the width of the blending area (θ) can be selected from a set of predefined values ​​{0, 1, 2, 4, 8}. The optimal blending area width can be determined for each GPM block at the encoder and signaled to the decoder based on syntax elements, such as merge_gpm_blending_width_idx. As an example, all predefined blending intensity values ​​can be shiftable, while all clipping and shifting operations within the GPM blending process can be kept without any changes.

[0070] Furthermore, the range of the weights can be expanded from [0,8] to [0,32] to accommodate the increased width of the GPM blending area. Specifically, the weights can be calculated as follows:

number

[0071] Wedge-based prediction is a hybrid prediction mode (e.g., in AV1) similar to GPM. Wedge-based prediction can be used for both inter-inter and inter-intra combinations. For example, a set of 16 coefficient arrays can be preset for each eligible block size. They effectively divide the coding block into two sections along various tilt angles. The boundaries of moving objects are often difficult to approximate by on-grid block partitions. A solution is to predefine a codebook of possible wedge partitions (e.g., 16) and signal a wedge index in the bitstream if a coding unit should be further partitioned in such a manner. In the current wedge design for AV1, 16 modes are supported because the multi-symbol adaptive context coding used in AV1 allows up to 16 symbols to be signaled with one syntax element. A 16-ary shape codebook, including horizontal, vertical, or diagonal (e.g., ±2 or ±0.5) partition directions, is designed for both square blocks 540 and rectangular blocks 542, as shown in FIG. 5D, corresponding to each partition mode. To mitigate unwanted high-frequency components often generated by directly juxtaposing two predictors, a soft-cliff-shaped 2D wedge mask can be used to smooth the edges around the desired partition (e.g., m(i,j) is close to 0.5 around the edges and gradually transforms to binary weights at both ends). Partition-based prediction is a prediction method that partitions the current block into sections and applies a different predictor to each section. GPM and wedge-based prediction (described above) are examples of partition-based prediction modes.

[0072] Inter-intra prediction modes are hybrid prediction modes that combine inter and intra predictors. The inter predictor for an inter-intra mode may be generated using a single predictor, as described elsewhere herein. In some embodiments, the intra predictor is limited to four intra prediction modes: DC, vertical, horizontal, and smooth. The inter and intra predictors may be combined in either smooth inter-intra mode or wedge inter-intra mode. In wedge inter-intra mode, the inter and intra predictors may be combined using a wedge mask. In smooth inter-intra mode, the mask used to combine the inter and intra predictors may depend on the intra mode. Exemplary normalized mask weights for vertical (vertical mask 552), horizontal (horizontal mask 554), smooth (smooth mask 556), and DC (DC mask 558) modes are shown in FIG. 5E.

[0073] Predictions can be combined in more advanced ways than simple averaging within a block, including smooth and sharp transition gradients in different directions (e.g., wedge-based prediction) and implicit masking based on the difference between two predictors. This allows a combination of two inter predictions or a combination of inter and intra predictions to be used in the same block. The AV1 wedge mode described above can be extended to allow wedge mode to be used with 64x64, 32x64, 64x32, 16x64, and 64x16 blocks. Furthermore, wedge mode (also called wedge partition mode) can be defined in Hessian norm form, where the angle indicates the direction of the partition boundary and the distance indicates the offset of the partition boundary from the center of the block. The angle can be quantized into values ​​(e.g., 20 values) using tangent values. The distance can be quantized based on the block size. For example, three distances can be used for angles greater than 180 degrees and angles of 0 or 90 degrees. Four distances can be used for other angles. In this way, 8×4+12×3=68 modes can be supported. Because more than 16 modes are supported, the wedge index can be signaled by three syntax elements: angular direction, angle, and distance. The angular direction indicates whether the angle is less than 180 degrees. Depending on the angular direction, the actual angle can be signaled. Depending on the signaled angle, the distance can be signaled.

[0074] The wedge blending mask can be quantized directly from the distance between the sample position and the split boundary. Using the Hessian norm form of the split boundary definition, the distance can be defined as:

number

number

[0075] The mixing weights at the corresponding positions can be derived using Equation 7:

number

[0076] The blending weights may be calculated on the fly (e.g., for low computational complexity) or may be pre-stored (e.g., similar to the AV1 wedge weight mode design).

[0077] In some systems, up to 68 wedge partition modes are supported. A wedge partition mode can consist of 20 angles and four offsets per angle (e.g., duplicate cases are removed). In the bitstream, the angle direction (whether the angle is greater or less than 180 degrees), the angle index, and the offset index can be signaled separately with three syntax elements. However, because the frequency of each wedge mode is different, a fixed order of mode signaling is not optimal. The methods and processes described below incorporate reordering the list of wedge partition modes (or other partition modes) to improve efficiency and / or reduce transmission bandwidth.

[0078] 6A is a flow diagram illustrating an encoding method 600 according to some embodiments. Method 600 may be performed in a computing system (e.g., server system 112, source device 102, or electronic device 120) including control circuitry and memory storing instructions executed by the control circuitry. In some embodiments, method 600 is performed by executing instructions stored in memory (e.g., memory 314) of the computing system.

[0079] The system receives (602) video data including a plurality of blocks, including a first block, where the first block is to be predicted using partition-based prediction. The system obtains (604) a set of partition modes, each uniquely associated with a partition line that partitions the first block into at least two partitions. The system generates (606) both a reference template using samples of the reference block and a reconstructed template using samples of the first block. For each partition mode in the set of partition modes, the system calculates (608) a cost between the reference template and the reconstructed template. The system reorders (610) the set of partition modes based on the calculated cost between the reference template and the reconstructed template for each partition mode. The system selects (612) a partition mode from the reordered set of partition modes. The system encodes (614) the first block using the selected partition mode. In some embodiments, the system transmits the encoded first block via a video bitstream. In some embodiments, the system transmits an index corresponding to the selected partition mode via the video bitstream.

[0080] 6B is a flow diagram illustrating a decoding method 650 according to some embodiments. Method 650 may be performed in a computing system (e.g., server system 112, source device 102, or electronic device 120) including control circuitry and memory storing instructions executed by the control circuitry. In some embodiments, method 650 is performed by executing instructions stored in memory (e.g., memory 314) of the computing system.

[0081] The system receives video data from a video bitstream (652), including a plurality of blocks, including a first block, where the first block includes at least two partitions and is to be predicted using partition-based prediction. The system obtains (654) a set of partition modes, each uniquely associated with a partition line that partitions the first block into at least two partitions. The system generates (656) both a reference template using samples of the reference block and a reconstructed template using samples of the first block. For each partition mode in the set of partition modes, the system calculates (658) a cost between the reference template and the reconstructed template. The system reorders (660) the set of partition modes based on the calculated cost between the reference template and the reconstructed template for each partition mode. The system selects (662) a partition mode from the reordered set of partition modes. The system reconstructs (664) the first block using the partition mode selected from the reordered set of partition modes.

[0082] 6A and 6B depict a number of logical steps in a particular order, some steps that are not order-dependent may be rearranged, and other steps may be combined or separated. The order and grouping presented herein is not exhaustive, as some rearrangements or other groupings not specifically mentioned will be apparent to those skilled in the art. Furthermore, it should be recognized that the steps may be implemented in hardware, firmware, software, or any combination thereof.

[0083] The systems described herein may be used for GPM or wedge-based partitioning. In some embodiments, at the decoder side, partitioning modes (e.g., wedge partition modes) are reordered according to available decoder-side information. A reordered wedge partition mode list is generated, and an index with a maximum value N (where N is less than or equal to the maximum number of partition modes) may be parsed to indicate the position of the best partition mode within the reordered partition mode list. The index may be coded using multi-symbol entropy coding, and the index maximum value may be predefined or signaled in a high-level syntax.

[0084] In some embodiments, the reordering depends on the cost of the templates. For example, a reference template is generated using the top M rows and left M columns of integer-positioned samples of the reference block based on the integer values ​​of the motion vectors (MVs) of each partition, and is further blended using the partition modes. A reconstructed template is generated using the top M rows and left M columns of samples of the current block in the current frame. The cost between the reference template and the reconstructed template is calculated for all partition modes, and the modes are reordered accordingly. By using only integer-positioned samples in the reference frame, the interpolation process is avoided and the decoder-side complexity is reduced. Specifically, the disclosed method (e.g., B1 described below) can obtain a set of partition modes, where each partition mode is uniquely associated with a partition line that partitions the first block into at least two partitions. The disclosed method can then generate a reference template using samples of the reference block and a reconstructed template using samples of the current block. Furthermore, the disclosed method can calculate a cost between the reference template and the reconstructed template for each partition mode in the set of partition modes, and reorder the set of partition modes based on the calculated cost. The disclosed method can then select a partition mode from the set of reordered partition modes and reconstruct the current block using the selected partition mode.

[0085] In some embodiments, the reference template is generated using the top M rows and left M columns of fractionally positioned samples of the reference block (interpolated using the parsed MVs) and blended using one partition mode. The use of fractionally positioned samples of the reference frame improves the accuracy of the template generation and therefore the accuracy of the reordering.

[0086] In some embodiments, the partition modes and partition codes indicating which portions are predictor 1 and which portions are predictor 2 are listed together and reordered, and the top N best modes (e.g., the 48 best modes) are used. The partition modes and partition codes can be signaled together or separately as indices into the reordered mode / code list.

[0087] In some embodiments, the partition code is signaled and, depending on the partition code, the partition modes are reordered. The top N best modes may be used and an index indicating the position of the best mode in the reordered list may be signaled.

[0088] In some embodiments, the signaling of partition mode is separated as a partition angle and a partition offset, where the angles are reordered (as described above) and the index indicates the position in the reordered angle list. In some embodiments, the signaling of partition mode is separated as a partition angle and a partition offset, where the offset for each angle is reordered (as described above) and the index indicates the position in the reordered offset list.

[0089] In some embodiments, when signaling the top N best modes, the indices are further grouped into different groups, and the group index (e.g., wedge_group_idx) is signaled first, and then the relative index of the selected partition mode within the selected group (e.g., wedge_group_mode_idx) is further signaled. In some embodiments, which wedge division modes are included in a particular wedge group is determined by the associated reordered index. For example, the number of wedge division modes in a group is 16 or less. In some embodiments, the group index (wedge_group_idx) and / or the selected wedge division mode (wedge_group_mode_idx) are signaled using multi-symbol arithmetic coding.

[0090] (A1) In one aspect, some embodiments include a method of video encoding (e.g., method 600). In some embodiments, the method is performed in a computing system (e.g., server system 112) having memory and control circuitry. In some embodiments, the method is performed in a coding module (e.g., coding module 320). In some embodiments, the method is performed in a source coding component (e.g., source coder 202), a coding engine (e.g., coding engine 212), and / or an entropy coder (e.g., entropy coder 214). The method includes: (i) receiving video data including a plurality of blocks, including a first block and a reference block associated with the first block, where the first block is to be predicted by partition-based prediction; (ii) obtaining a set of partition modes, where each partition mode is uniquely associated with a partition line that partitions the first block into at least two partitions; (iii) generating both a reference template using samples of the reference block and a reconstructed template using samples of the first block; (iv) calculating, for each partition mode in the set of partition modes, a cost between the reference template and the reconstructed template; (v) reordering the set of partition modes based on the calculated cost between the reference template and the reconstructed template for each partition mode; (vi) selecting a partition mode from the reordered set of partition modes; and (vii) encoding the first block using the partition mode selected from the reordered set of partition modes. In some embodiments, each partition mode in the set of partition modes corresponds to a respective partition code in a set of partition codes, and reordering the set of partition modes based on the reference template includes reordering the set of partition codes.In some embodiments, each partition mode in the set of partition modes corresponds to a respective partition code in a set of partition codes, a first partition code in the set of partition codes being signaled in the video bitstream, and the set of partition modes being reordered based on the first partition code. In some embodiments, each partition mode in the set of partition modes corresponds to a respective partition angle in the set of partition angles and a respective partition offset in the set of partition offsets, and reordering the set of partition modes includes reordering the set of partition angles. In some embodiments, each partition mode in the set of partition modes corresponds to a respective partition angle in the set of partition angles and a respective partition offset in the set of partition offsets, and reordering the set of partition modes includes reordering the set of partition offsets. In some embodiments, the reordered set of partition modes is grouped into a plurality of groups, and the method further includes signaling an index of a selected partition mode and signaling a group index of a selected group among the plurality of groups, the index being a relative index of a first partition mode in the selected group.

[0091] (A2) In some embodiments of A1, the method further includes transmitting an index corresponding to the selected partition mode via the video bitstream.

[0092] (A3) In some embodiments of A1 or A2, the reference template is generated using the top row and left column of integer-position samples of the reference block, and the reconstruction template is generated using the top row and left column of samples of the first block.

[0093] (A4) In some embodiments of any of A1-A3, the reference template is further generated using additional fractional samples of the reference block. In some embodiments, the reference template is generated using integer samples of the reference block and blended with the additional fractional samples of the reference block.

[0094] (A5) In some embodiments of any of A1-A4, the reordered set of partition modes is a subset of the set of partition modes. For example, the reordered set of partition modes corresponds to the top M modes based on template cost. In some embodiments, the reordered set of partition modes is a subset of the set of partition modes, and indices of the reordered set of partition modes are obtained from a video bitstream.

[0095] (A6) In some embodiments of any of A1-A5, the index of the selected partition mode is coded using multi-symbol entropy coding. In some embodiments, the maximum value of the index is predefined or signaled in a high-level syntax. For example, the high-level syntax corresponds to the sequence level, frame level, slice level, or tile level. In some embodiments, the high-level syntax is higher than the block level. By way of example, the high-level syntax may include a video parameter set (VPS), a sequence parameter set (SPS), a picture parameter set (PPS), an adaptation parameter set (APS), a slice header, a picture header, a tile header, and / or a CTU header.

[0096] (B1) In another aspect, some embodiments include a method of video decoding (e.g., method 650). In some embodiments, the method is performed in a computing system (e.g., server system 112) having memory and control circuitry. In some embodiments, the method is performed in a coding module (e.g., coding module 320). In some embodiments, the method is performed in a parser (e.g., parser 254), a motion prediction component (e.g., motion compensated prediction unit 260), and / or an intra-prediction component (e.g., intra-picture prediction unit 262). The method includes: (i) receiving video data (e.g., a coded video sequence) from a video bitstream, the video data including a plurality of blocks including a first block and a reference block associated with the first block, the first block to be predicted by partition-based prediction; (ii) obtaining a set of partition modes (e.g., the wedge modes of FIG. 5D ), each partition mode being uniquely associated with a partition line that partitions the first block into at least two partitions; (iii) generating both a reference template using samples of the reference block and a reconstructed template using samples of the first block; (iv) calculating, for each partition mode in the set of partition modes, a cost between the reference template and the reconstructed template; (v) reordering the set of partition modes based on the calculated cost between the reference template and the reconstructed template for each partition mode; (vi) selecting a partition mode from the reordered set of partition modes; and (vii) reconstructing the first block using the partition mode selected from the reordered set of partition modes. For example, the set of partition modes is a set of wedge partition modes. As another example, the set of partition modes is a set of geometric partition modes. As another example, at the decoder side, the wedge division modes are reordered according to available decoder side information to generate a reordered wedge division mode list.In some embodiments, the reference template is generated using only samples of the reference block that correspond to integer values, for example, the reference template is generated using the top M rows and left M columns of integer-position samples of the reference block based on the integer values ​​of the motion vectors (MVs) of each wedge partition, and then blended using one wedge partition mode.

[0097] (B2) In some embodiments, the reference template is generated using the top row and left column of integer-positioned samples of the reference block, and the reconstructed template is generated using the top row and left column of samples of the first block. In this example, the reconstructed template is generated using the top M rows and left M columns of samples of the current block in the current frame. The cost between the reference template and the reconstructed template is calculated for all wedge division modes, and all of these modes are reordered accordingly. By using only integer-positioned samples in the reference frame, the interpolation process is avoided and the complexity on the decoder side is reduced.

[0098] (B3) In some embodiments of B1 or B2, the reference template is further generated using additional fractional samples of the reference block. For example, the reference template is generated using the top M rows and left M columns of fractionally positioned samples of the reference block (interpolated using the parsed MVs) and blended using a wedge division mode. In this example, the reconstructed template is generated using the top M rows and left M columns of samples of the current block in the current frame. The cost between the reference template and the reconstructed template is calculated for all wedge division modes, and all of these modes are reordered accordingly. Using fractionally positioned samples of the reference frame improves the accuracy of the template generation, and therefore the accuracy of the reordering. In some embodiments, the reference template is generated using integer samples of the reference block and blended using additional fractional samples of the reference block.

[0099] (B4) In some embodiments of any of B1-B3, the reordered set of partition modes is a subset of the set of partition modes. For example, the top N best modes (top 48 modes out of a total of 80 modes) are included in the reordered set. In some embodiments, the index of the reordered set of partition modes is obtained from the video bitstream.

[0100] (B5) In some embodiments of any of B1 to B4, each partition mode in the set of partition modes corresponds to a respective partition code in the set of partition codes, and reordering the set of partition modes based on the reference template includes reordering the set of partition codes. For example, the wedge partition modes and the wedge codes indicating which portions are predictor 1 and which portions are predictor 2 are listed together and reordered, and optionally, the top N best modes are used. In some embodiments, the set of partition modes and the set of partition codes are signaled separately. For example, the wedge partition modes and the wedge codes may be signaled together or separately as indices of the reordered mode / code list.

[0101] (B6) In some embodiments of any of B1 to B4, each partition mode in the set of partition modes corresponds to a respective partition code in a set of partition codes, a first partition code in the set of partition codes is signaled in the video bitstream, and reordering the set of partition modes includes reordering the set of partition modes based on the first partition code. For example, a wedge code is signaled first, and the wedge partition modes are reordered according to the wedge code. The top N best modes are used, and an index indicating the position of the best mode in the reordered list is signaled.

[0102] (B7) In some embodiments of any of B1 to B4, each partition mode in the set of partition modes corresponds to a respective partition angle in the set of partition angles and a respective partition offset in the set of partition offsets, and reordering the set of partition modes includes reordering the set of partition angles. For example, signaling of a wedge partition mode is separated into a wedge angle and a wedge offset. In this example, the angles are reordered, and the index indicates a position in the reordered angle list.

[0103] (B8) In some embodiments of any of B1 to B4, each partition mode in the set of partition modes corresponds to a respective partition angle in the set of partition angles and a respective partition offset in the set of partition offsets, and reordering the set of partition modes includes reordering the set of partition offsets. For example, signaling of a wedge partition mode is separated into a wedge angle and a wedge offset. In this example, the offsets for each angle are reordered, and an index indicates a position in the reordered offset list.

[0104] (B9) In some embodiments of any of B1 to B8, the reordered set of partition modes is grouped into multiple groups, and the method further includes signaling a group index of a selected group of the multiple groups, where the index is a relative index of a first partition mode in the selected group. For example, the indexes are grouped into different groups, and a group index (wedge_group_idx) is first signaled, and then a relative index (wedge_group_mode_idx) of a selected wedge partition mode within the selected group is further signaled. In some embodiments, the multiple groups correspond to the top N best modes. In some embodiments, a particular partition mode in the reordered set of partition modes is assigned to a particular group of the multiple groups based on an associated reordered index. For example, which wedge partition modes are included in a particular wedge group are determined by their associated reordered index. By way of example, the number of wedge partition modes in a group is 16 or less.

[0105] (B10) In some embodiments of any of B1-B9, the index is coded using multi-symbol entropy coding. For example, the group index (wedge_group_idx) and / or the selected wedge division mode (wedge_group_mode_idx) are signaled using multi-symbol arithmetic coding.

[0106] (B11) In some embodiments of any of B1-B10, the maximum value of the index is predefined or signaled in high-level syntax. By way of example, an index with a maximum value N (where N is less than or equal to the maximum number of wedge division modes) is parsed to indicate the position of the best wedge division mode within the reordered wedge mode list. For example, the maximum index value N is predefined or signaled in high-level syntax.

[0107] In another aspect, some embodiments include a computing system including a control circuit (e.g., control circuit 302) and a memory (e.g., memory 314) coupled to the control circuit, the memory storing one or more instructions configured to be executed by the control circuit, the one or more instructions including instructions for performing any of the methods described herein (e.g., A1-A6 and B1-B11 above).

[0108] In yet another aspect, some embodiments include a non-transitory computer-readable storage medium that stores one or more instructions for execution by control circuitry of a computing system, the one or more instructions including instructions for performing any of the methods described herein (e.g., A1-A6 and B1-B11 above).

[0109] Although terms such as "first," "second," and the like may be used herein to describe various elements, it will be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. The terminology used herein is intended to describe particular embodiments only and is not intended to be limiting on the scope of the claims. As used in the description of embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or," as used herein, will also be understood to refer to and encompass any and all possible combinations of one or more of the associated listed items. Furthermore, the terms "comprises" and / or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0110] As used herein, the term "if" can be interpreted to mean "when" or "upon" or "in response to determining" or "in accordance with a determination" or "in response to detecting" the preceding condition is true, depending on the context. Similarly, "if it is determined that [the preceding condition is true]" or "if [the preceding condition is true]" or "when [the preceding condition is true]" can be interpreted to mean "upon determining" or "in response to determining" or "in accordance with a determination" or "detecting" or "in response to detecting" the preceding condition is true, depending on the context.

[0111] The above description has been set forth with reference to specific embodiments for purposes of explanation. However, the above illustrative discussion is not intended to be exhaustive or to limit the scope of the claims to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described to best explain and thereby enable those skilled in the art the principles of operation and practical applications.

[0112] [Related Applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 443,360, filed February 3, 2023, entitled "Improvement of Wedge-Based Prediction Modes Reordering," and is a continuation of and claims priority to U.S. Patent Application No. 18 / 244,837, filed September 11, 2023, entitled "Systems and Methods for Partition-Based Prediction Mode Reordering."

Claims

1. 1. A method of video decoding executed on a computing system having a memory and one or more processors, comprising: receiving video data from a video bitstream, the video data including a plurality of blocks including a first block and a reference block associated with the first block, the first block including at least two partitions and predicted using partition-based prediction; obtaining a set of partition modes, each partition mode being uniquely associated with a partition line that partitions the first block into the at least two partitions; generating both a reference template using samples of the reference block and a reconstruction template using samples of the first block; For each partition mode in the set of partition modes, calculating a cost between the reference template and the reconstructed template; reordering the set of partition modes based on the calculated cost between the reference template and the reconstruction template for each partition mode; selecting a partition mode from the reordered set of partition modes; reconstructing the first block using the partition mode selected from the reordered set of partition modes; A method having the following.

2. the reference template is generated using the top row and left column of integer-position samples of the reference block, and the reconstruction template is generated using the top row and left column of samples of the first block. The method of claim 1.

3. the reference template is generated using integer samples of the reference block and blended with additional fractional samples of the reference block; The method of claim 1.

4. the reordered set of partition modes is a subset of the set of partition modes, and indices of the reordered set of partition modes are obtained from the video bitstream. The method of claim 1.

5. each partition mode in the set of partition modes corresponds to a respective partition code in a set of partition codes, and reordering the set of partition modes includes reordering the set of partition codes. The method of claim 1.

6. each partition mode in the set of partition modes corresponds to a respective partition code in a set of partition codes, a first partition code in the set of partition codes is signaled in the video bitstream, and the set of partition modes is reordered based on the first partition code; The method of claim 1.

7. each partition mode in the set of partition modes corresponds to a respective partition angle in a set of partition angles and a respective partition offset in a set of partition offsets, and reordering the set of partition modes includes reordering the set of partition angles; The method of claim 1.

8. each partition mode in the set of partition modes corresponds to a respective partition angle in a set of partition angles and a respective partition offset in a set of partition offsets, and reordering the set of partition modes includes reordering the set of partition offsets; The method of claim 1.

9. the set of reordered partition modes is grouped into a plurality of groups; The method further comprises signaling an index of the selected partition mode and a group index of a selected group from the plurality of groups; the index is a relative index of the selected partition mode of the selected group; The method of claim 1.

10. The index of the selected partition mode is coded using multi-symbol entropy coding. The method of claim 1.

11. The maximum value of the index of the selected partition mode is predefined or signaled in a high-level syntax. The method of claim 1.

12. a control circuit; Memory and and one or more instructions stored in the memory and configured for execution by the control circuitry, the one or more instructions, when executed by the control circuitry, causing the control circuitry to perform the method of any one of claims 1 to 11. Computing system.

13. A computer program which, when executed by a computing device, causes the computing device to perform the method of any one of claims 1 to 11.

14. 1. A method of video encoding executed on a computing system having a memory and one or more processors, comprising: receiving video data including a plurality of blocks including a first block and a reference block associated with the first block, the first block being predicted using partition-based prediction; obtaining a set of partition modes, each partition mode being uniquely associated with a partition line that partitions the first block into at least two partitions; generating both a reference template using samples of the reference block and a reconstruction template using samples of the first block; For each partition mode in the set of partition modes, calculating a cost between the reference template and the reconstructed template; reordering the set of partition modes based on the calculated cost between the reference template and the reconstruction template for each partition mode; selecting a partition mode from the reordered set of partition modes; encoding the first block using the partition mode selected from the reordered set of partition modes; A method having the following.

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