System and Method for Building an Intramode List

Abstract

Various embodiments described herein include methods and systems for encoding and decoding video. In one embodiment, a video decoding method includes receiving video data from a video bitstream, the first block being encoded in inter-intra prediction mode. The method also includes generating a list of intra-prediction modes for the first block and identifying an intra-prediction mode from the list of intra-prediction modes for the intra-prediction of the first block. The method further includes decoding the first block using intra-prediction and inter-prediction.

Description

Technical Field

[0001] Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 443,361, filed February 3, 2023, entitled "Improvement of Wedge-Based Interintra Prediction with Mode List," and is a continuation application of U.S. Patent Application No. 18 / 244,835, filed September 11, 2023, entitled "Systems and Methods for Constructing Intra Mode Lists," and claims priority.

[0002] The disclosed embodiments generally relate to video coding, which includes, but is not limited to, systems and methods for constructing intra mode lists for inter-intra prediction.

Background Art

[0003] Digital video is supported by various 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. Since the bandwidth capacity of communication networks is limited and the memory resources of recording devices are limited, video coding can be used to compress video data according to one or more video coding standards before the video data is communicated or recorded.

[0004] Multiple video codec standards have been developed. For example, video coding standards include AOMedia Video 1 (AV1), Multipurpose Video Coding (VVC), Joint Exploration Test Model (JEM), High Efficiency Video Codec (HEVC / H.265), Advanced Video Coding (AVC / H.264), and Moving Picture Expert Group (MPEG) coding. Video coding generally utilizes prediction methods (e.g., interpretation, intrapretation) that take advantage of 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 a decrease in video quality.

[0005] HEVC, also known as H.265, is a video compression standard designed as part of the MPEG-H project. The ITU-T and ISO / IEC published the HEVC / H.265 standard in 2013 (version 1), 2014 (version 2), 2015 (version 3), and 2016 (version 4). Multipurpose Video Coding (VVC), also known as H.266, is a video compression standard intended as a successor to HEVC. The 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 an alternative to HEVC. A valid version 1.0.0, including errata 1 of this specification, was released on January 8, 2019. [Overview of the Initiative]

[0006] As will be explained in more detail below, in some current systems, wedge inter-intramodes and smooth inter-intramodes share the same hardcoded intramodes. These hardcoded intramodes may be DC, vertical, horizontal, and smooth. However, adaptive intramode lists for wedge inter-intramodes and / or smooth inter-intramodes can improve coding efficiency (e.g., by excluding unsuitable modes and promoting high-probability modes). Furthermore, some partition boundary angles may be unsuitable for intramodes. These angles may be excluded from wedge inter-intra predictions to improve coding efficiency.

[0007] According to several embodiments, a method for video decoding is provided. The method includes (i) receiving video data from a video bitstream, the first block comprising a plurality of blocks comprising a first block, the first block being encoded with inter-intra prediction, (ii) generating a list of intra-prediction modes for the first block, the list having size N, (iii) identifying the intra-prediction modes of the list of intra-prediction modes for intra-prediction of the first block, and (iv) decoding the first block using intra-mode prediction and inter-mode prediction.

[0008] According to several embodiments, a method for video coding is provided. The method includes (i) receiving video data comprising a plurality of blocks including a first block, the first block being coded by inter-intra prediction, (ii) generating a list of intra-modes for the first block, the list having size N, (iii) identifying the intra-modes of the list of intra-prediction modes for intra-coding of the first block, and (iv) coding the first block using intra-mode coding and inter-mode coding.

[0009] According to some embodiments, computing systems such as streaming systems, server systems, personal computer systems, or other electronic devices are provided. The computing system includes a control circuit and a memory for recording one or more instruction sets. One or more instruction sets include instructions for performing any of the methods described herein. In some embodiments, the computing system includes encoder components and decoder components (e.g., transcoder components).

[0010] According to some embodiments, a non-temporary computer-readable recording medium is provided. The non-temporary computer-readable recording medium records one or more instruction sets for execution by a computing system. One or more instruction sets include instructions for executing any of the methods described herein.

[0011] Accordingly, devices and systems are disclosed using methods for encoding and decoding video. Such methods, devices, and systems can complement or replace conventional methods, devices, and systems for video encoding / decoding.

[0012] The features and advantages described herein are not necessarily exhaustive, and in particular, several additional features and advantages will be apparent to those skilled in the art in consideration of the drawings, specification and claims provided herein. Furthermore, it should be noted that the language used herein has been chosen primarily for readability and explanatory purposes and not necessarily to describe or limit the subject matter described herein. [Brief explanation of the drawing]

[0013] To enable a more detailed understanding of this disclosure, a more detailed description can be provided by referring to the features of various embodiments, some of which are shown in the accompanying drawings. However, the accompanying drawings are merely illustrative of the relevant features of this disclosure and should not necessarily be considered limiting, as other effective features can be recognized by those skilled in the art as they will understand by reading this disclosure.

[0014] [Figure 1] This block diagram shows an exemplary communication system in several embodiments. [Figure 2A] This is a diagram showing exemplary elements of encoder components according to several embodiments. [Figure 2B] This is a block diagram illustrating exemplary elements of decoder components according to several embodiments. [Figure 3] This is a diagram illustrating exemplary server systems in several embodiments. [Figure 4A] This shows exemplary coding tree structures in several embodiments. [Figure 4B] This shows exemplary coding tree structures in several embodiments. [Figure 4C] This shows exemplary coding tree structures in several embodiments. [Figure 4D] This shows exemplary coding tree structures in several embodiments. [Figure 5A] Examples of partition-based prediction modes in several embodiments are shown. [Figure 5B] This shows exemplary blending of split modes in several embodiments. [Figure 5C] This shows exemplary blending of split modes in several embodiments. [Figure 5D] Examples of wedge-based partitioning according to several embodiments are shown. [Figure 5E] The following are exemplary inter-intramask weights according to several embodiments. [Figure 6A] A flowchart showing an exemplary method of encoding video according to some embodiments. [Figure 6B] A flowchart showing an exemplary method of decoding video according to some embodiments.

[0015] According to a general implementation, the various features shown in the drawings are not necessarily drawn to scale, and like reference numerals can be used throughout the specification and drawings to indicate like features.

Best Mode for Carrying Out the Invention

[0016] The present disclosure describes, among other things, using various splitting techniques for splitting video blocks for better motion prediction and higher quality encoding. The present disclosure also describes constructing the intra mode list of the current block for use in an intra mode prediction unit of wedge inter-intra or smooth inter-intra prediction. The size of the intra mode list is shown as N and may be predefined or signaled in high-level syntax. N may be a positive integer such as 4 or 6. By adaptively constructing the intra mode list in this way, coding efficiency can be improved by excluding inappropriate modes and / or promoting high probability modes.

[0017] Exemplary Systems and Devices FIG. 1 is a block diagram showing a communication system 100 according to some embodiments. The communication system 100 includes a source device 102 and a plurality of electronic devices 120 (e.g., electronic devices 120-1 to electronic devices 120-m) communicatively connected to each other via one or more networks. In some embodiments, the communication system 100 is a streaming system for use in video-enabled applications such as, for example, video conferencing applications, digital TV applications, and media storage and / or distribution applications.

[0018] The source device 102 includes a video source 104 (e.g., a camera component or media recording) and an encoder component 106. In some embodiments, the video source 104 is a digital camera (e.g., configured to generate an uncompressed video sample stream). The encoder component 106 generates one or more encoded video bitstreams from the video stream. The video stream from the video source 104 can be a large amount of data compared to the encoded video bitstream 108 generated by the encoder component 106. The encoded video bitstream 108 has a smaller amount of data (less data) compared to the video stream from the video source, so the encoded video bitstream 108 requires less bandwidth for transmission and less recording space for recording compared to the video stream from the video source 104. In some embodiments, the source device 102 does not include the encoder component 106 (e.g., is configured to transmit uncompressed video data to the network 110).

[0019] One or more networks 110 represent any number of networks that transmit information between the source device 102, the server system 112, and / or the electronic device 120, including, for example, wired and / or wireless communication networks. One or more networks 110 may exchange data over circuit-switched channels and / or packet-switched channels. Typical networks include telecommunications networks, local area networks, wide area networks, and / or the Internet.

[0020] One or more networks 110 include a server system 112 (e.g., a distributed / cloud computing system). In some embodiments, the server system 112 is or includes a streaming server (e.g., configured to record and / or distribute video content such as an encoded video stream from a source device 102). The server system 112 includes a coder component 114 (e.g., configured to encode and / or decode video data). In some embodiments, the coder component 114 includes an encoder component and / or a decoder component. In various embodiments, the coder component 114 is instantiated as hardware, software, or a combination thereof. In some embodiments, the coder component 114 is configured to decode an encoded video bitstream 108 and re-encode the video data using different encoding standards and / or methodologies to produce encoded video data 116. In some embodiments, the server system 112 is configured to generate multiple video formats and / or encodings from the encoded video bitstream 108.

[0021] In some embodiments, the server system 112 functions as a Media-Aware Network Element (MANE). For example, the server system 112 may be configured to prune an encoded video bitstream 108 to adapt a potentially different bitstream to one or more of the electronic devices 120. In some embodiments, a MANE is provided separately from the server system 112.

[0022] Electronic device 120-1 includes a decoder component 122 and a display 124. In some embodiments, the decoder component 122 is configured to decode encoded video data 116 to produce an output video stream that can be rendered on a display or other type of rendering device. In some embodiments, one or more of the electronic devices 120 do not include a display component (e.g., are communicatively coupled to an external display device and / or include media recording). In some embodiments, the electronic device 120 is a streaming client. In some embodiments, the electronic device 120 is configured to access a server system 112 to retrieve encoded video data 116.

[0023] The source device and / or multiple electronic devices 120 may also be referred to as “terminal devices” or “user devices.” In some embodiments, one or more of the source device 102 and / or 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 video conferencing device, and / or other types of electronic devices.

[0024] In an exemplary operation of the communication system 100, source device 102 transmits an encoded video bitstream 108 to server system 112. For example, source device 102 may encode a stream of pictures captured by the source device. Server system 112 receives the encoded video bitstream 108 and may decode and / or encode the encoded video bitstream 108 using coder components 114. For example, server system 112 may apply encoding to the video data that is best suited for network transmission and / or recording. Server system 112 may transmit the encoded video data 116 (e.g., one or more encoded video bitstreams) to one or more of the electronic devices 120. Each electronic device 120 may decode the encoded video data 116 to restore the video picture and optionally display it.

[0025] Figure 2A is a block diagram showing exemplary elements of an encoder component 106 according to several embodiments. The encoder component 106 receives a source video sequence from a video source 104. In some embodiments, the encoder component includes a receiver (e.g., a transceiver) component configured to receive the source video sequence. In some embodiments, the encoder component 106 receives a video sequence from a remote video source (e.g., a video source that is a component of a device different from the encoder component 106). The video source 104 can provide the source video sequence in the form of a digital video sample stream, which may be of any suitable bit depth (e.g., 8-bit, 10-bit, or 12-bit), any color space (e.g., BT.601 Y CrCB, or RGB), and any suitable sampling structure (e.g., Y CrCb 4:2:0 or Y CrCb 4:4:4). In some embodiments, the video source 104 is a recording device that records previously captured / prepared video. In some embodiments, the video source 104 is a camera that captures local image information as a video sequence. Video data may be provided as a series of individual pictures that, when viewed sequentially, give the impression of motion. Each picture itself can be organized as a spatial array of pixels, and each pixel 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 explanation will focus on samples.

[0026] The encoder component 106 is configured to obtain a coded video sequence 216 by coding and / or compressing pictures of a source video sequence in real time or under other time constraints required by the application. Adhering to an appropriate coding speed is one function of the controller 204. In some embodiments, the controller 204 controls and is functionally coupled to other functional units, as 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, picture group (GOP) layout, maximum motion vector search range, etc. Those skilled in the art will readily be able to identify other functions of the controller 204 that may be related to the encoder component 106 optimized for a particular system design.

[0027] 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 (responsible for generating symbols, such as a symbol stream, based on, for example, the input picture and / or reference picture(s) to be coded) and a (local) decoder 210. The decoder 210, like a (remote) decoder (if the compression between the symbols and the coded video bitstream is reversible), reconstructs the symbols to generate sample data. The reconstructed sample stream (sample data) is input to the reference picture memory 208. Since decoding the symbol stream yields bit-exact results regardless of the decoder location (local or remote), the contents in the reference picture memory 208 are also bit-exact between the local encoder and the remote encoder. In this way, the predictive unit of the encoder interprets the same sample values ​​as the decoder interprets when using predictions during decoding, as reference picture samples. The principle of reference picture synchronization (and the resulting drift when synchronization cannot be maintained, for example, due to channel errors) is known to those skilled in the art.

[0028] The operation of decoder 210 may be the same as that of a remote decoder, such as decoder component 122, which will be described in detail below in relation to Figure 2B. However, referring briefly to Figure 2B, since symbols are available and the encoding / decoding of symbols to the coded video sequence by the entropy coder 214 and parser 254 may be reversible, the entropy decoding portion of decoder component 122, including buffer memory 252 and parser 254, does not need to be fully implemented in local decoder 210.

[0029] The decoder techniques described herein may exist in substantially the same functional form as the corresponding encoders, except for syntactic parsing / entropy decoding. Therefore, the disclosed subject matter focuses on decoder operation. Descriptions of encoder techniques can be omitted as they may be the reverse of decoder techniques. More detailed explanations are required only in specific areas and are provided below.

[0030] As part of its operation, the source coder 202 can perform motion-compensated predictive coding, predictively coding the input frame by referencing one or more previously coded frames from a video sequence designated as a reference frame. In this way, the coding engine 212 codes the difference between the pixel blocks of the input frame and the pixel blocks of the reference frame(s) that may be selected as predictive references for the input frame. The controller 204 can manage the coding operation of the source coder 202, including, for example, setting parameters and subgroup parameters used to encode the video data.

[0031] The decoder 210 decodes the coded video data of a frame that may be designated as a reference frame, based on the symbols generated by the source coder 202. The operation of the coding engine 212 may be advantageously a lossy process. When the coded video data is decoded by a video decoder (not shown in Figure 2A), the reconstructed video sequence may be a copy of the source video sequence with some errors. The decoder 210 can replicate the decoding process that may be performed by a remote video decoder on the reference frame, and have the reconstructed reference frame recorded in the reference picture memory 208. In this way, the encoder component 106 locally records a copy of the reconstructed reference frame that has content common to the reconstructed reference frame that will be obtained (without transmission errors) by the remote video decoder.

[0032] The predictor 206 can perform predictive searches on the coding engine 212. That is, for a new frame to be coded, the predictor 206 can search the reference picture memory 208 to find sample data (as candidate reference pixel blocks) or specific metadata such as motion vectors and block shapes of reference pictures that can serve as appropriate predictive references for the new picture. The predictor 206 can operate sample block by sample block to find appropriate predictive references. In some cases, the input picture may have predictive references drawn from multiple reference pictures recorded in the reference picture memory 208, as determined by the search results obtained by the predictor 206.

[0033] The outputs of all the aforementioned functional units may undergo entropy coding in the entropy coder 214. The entropy coder 214 converts the symbols generated by the various functional units into coded video sequences by reversibly compressing the symbols according to techniques known to those skilled in the art (e.g., Huffman coding, variable-length coding, and / or arithmetic coding).

[0034] In some embodiments, the output of the entropy coder 214 is coupled to the transmitter. The transmitter may be configured to buffer the coded video sequence(s) generated by the entropy coder 214 in preparation for transmission over a communication channel 218, which may be a hardware / software link to a recording device that records coded video data. The transmitter may be configured to merge the coded video data from the source coder 202 with other data being transmitted, such as coded audio data and / or auxiliary data streams (source 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 time / space / SNR enhancement layers, other forms of redundant data such as redundant pictures and slices, Supplementary Enhancement Information (SEI) messages, Visual Usability Information (VUI) parameter set fragments, and the like.

[0035] The controller 204 can manage the operation of the encoder components 106. During coding, the controller 204 can assign a specific coded picture type to each coded picture, which can influence the coding technique applied to each picture. For example, a picture may be assigned as an intra-picture (I-picture), a predictive picture (P-picture), or a bidirectional picture (B-picture). An intra-picture can be coded and decoded without using other frames in the sequence as a source for prediction. Some video codecs consider different types of intra-pictures, including, for example, Independent Decoder Refresh (IDR) pictures. Those skilled in the art will recognize their variations of I-pictures, as well as their respective uses and characteristics, and therefore will not repeat them here. A predictive picture may be coded and decoded using intra-prediction, or inter-prediction using up to one motion vector and reference index, to predict the sample values ​​of each block. A bidirectional predictive picture may be coded and decoded using intra-prediction or inter-prediction, which uses up to two motion vectors and reference indices, to predict the sample values ​​for each block. Similarly, a multi-predictive picture may use three or more reference pictures and associated metadata for the reconstruction of a single block.

[0036] A source picture may generally be spatially subdivided into multiple sample blocks (e.g., blocks of 4x4, 8x8, 4x8, or 16x16 samples each), and each block may be coded. Blocks may be coded predictively by referencing other (already coded) blocks, as determined by the coding assignment applied to each picture in the block. For example, a block of I pictures may be coded unpredictably or predictively by referencing already coded blocks of the same picture (spatial prediction or intra-prediction). Pixel blocks of a P picture may be coded unpredictably via spatial prediction or temporal prediction by referencing one previously coded reference picture. Blocks of a B picture may be coded unpredictably via spatial prediction or temporal prediction by referencing one or two previously coded reference pictures.

[0037] Video may be captured chronologically as multiple source pictures (video pictures). Intra-picture prediction (often abbreviated as intra-prediction) utilizes spatial correlations within a given picture, while inter-picture prediction utilizes (temporal or other) correlations between pictures. In one example, a particular picture being encoded / decoded, called the current picture, is divided into multiple blocks. When a block in the current picture is analogous to 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 in the reference picture and may have a third dimension to identify the reference picture if multiple reference pictures are used.

[0038] The encoder component 106 may perform coding operations in accordance with a predetermined video coding technique or standard, such as any of those described herein. In these operations, the encoder component 106 may perform various compression operations, including predictive coding operations that utilize temporal and spatial redundancy in the input video sequence. Thus, the coded video data may conform to the syntax specified by the video coding technique or standard being used.

[0039] Figure 2B is a block diagram showing exemplary elements of a decoder component 122 according to some embodiments. The decoder component 122 in Figure 2B is coupled to channel 218 and display 124. In some embodiments, the decoder component 122 includes a transmitter coupled to a loop filter 256 and configured to transmit data to the display 124 (e.g., via a wired or wireless connection).

[0040] In some embodiments, the decoder component 122 includes a receiver coupled to channel 218 and configured to receive data from channel 218 (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 the decoder component 122. In some embodiments, the decoding of each coded video sequence is independent of 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 that records coded video data. The receiver may receive coded video data having other data, e.g., coded audio data and / or auxiliary data streams, each of which may be transferred using entities (not shown). The receiver can isolate the coded video sequence from the other data. In some embodiments, the receiver receives additional (redundant) data having coded video. The additional data may be included as part of a coded video sequence(s). The additional data may be used by the decoder component 122 to decode the data and / or to more accurately reconstruct the original video data. The additional data may take the form of, for example, time, space, or SNR enhancement layers, redundant slices, redundant pictures, or forward error correction codes.

[0041] According to some embodiments, the decoder component 122 includes a buffer memory 252, a parser 254 (sometimes called an entropy decoder), a scaler / inverse unit 258, an intra-picture prediction unit 262, a motion compensation 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 an integrated circuit, a series of integrated circuits, and / or other electronic circuits. In some embodiments, the decoder component 122 is implemented at least partially in software.

[0042] Buffer memory 252 is coupled between channel 218 and parser 254 (for example, to counter 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, in addition to buffer memory 252 within decoder component 122 (for example, this is configured to handle playout timing), a separate buffer memory is provided outside decoder component 122 (for example, this is configured to handle playout timing). When receiving data from a recording / transferring device with sufficient bandwidth and controllability, or from an asynchronous network, buffer memory 252 may not be required or may be small. For use in best-effort packet networks such as the Internet, buffer memory 252 may be required, may be relatively large, may be advantageously adaptive in size, and may be at least partially implemented in an operating system or similar element (not shown) outside decoder component 122.

[0043] The 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 rendering devices such as the display 124. The control information for rendering devices may take the form of, for example, auxiliary enhancement information (SEI) messages or video usability information (VUI) parameter set fragments (not shown). The parser 254 parses (entropy decodes) the coded video sequence. The coding of the coded video sequence may follow video coding techniques or standards and may follow principles well known to those skilled in the art, including variable-length coding, Huffman coding, and arithmetic coding with or without context sensitivity. The parser 254 may extract from the coded video sequence a set of at least one subgroup parameters of subgroups of pixels in the video decoder, based on at least one parameter corresponding to a group. Subgroups may include groups of pictures (GOP), pictures, tiles, slices, macroblocks, coding units (CU), blocks, transform units (TU), and predictive units (PU). Parser 254 may also extract information from the coded video sequence, such as transform coefficients, quantizer parameter values, and motion vectors.

[0044] The reconstruction of symbol 270 may involve multiple different units, depending on the type of coded video picture or part thereof (e.g., interpicture and intrapicture, interblock and intrablock), as well as other factors. Which units are involved and how they are involved can be controlled by subgroup control information parsed from the video sequence coded by parser 254. For clarity, the flow of such subgroup control information between parser 254 and the following multiple units is not shown.

[0045] The decoder component 122 can be conceptually subdivided into several functional units, and in some implementations, these units can interact closely with each other and integrate with each other at least partially. However, for clarity, the conceptual subdivision of functional units is maintained herein.

[0046] The scaler / inverse unit 258 receives quantized transformation coefficients, as well as control information as symbols 270 (e.g., which transformation to use, block size, quantization coefficients, and / or quantization scaling matrix) from the parser 254. The scaler / inverse unit 258 can output a block containing sample values ​​that can be input to the aggregator 268.

[0047] In some cases, the output samples from the scaler / inverse unit 258 relate to an intracoded block that does 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 can be provided by the intrapicture prediction unit 262. The intrapicture prediction unit 262 may generate a block of the same size and shape as the block to be reconstructed using the surrounding reconstructed information extracted from the current (partially reconstructed) picture fetched from the picture memory 264. The aggregator 268 may add the prediction information generated by the intrapicture prediction unit 262 to the output sample information from the scaler / inverse unit 258 on a sample-by-sample basis.

[0048] In other cases, the output samples of the scaler / inverse unit 258 relate to an intercoded and potentially motion-compensated block. In such cases, the motion-compensated prediction unit 260 can access the reference picture memory 266 to fetch samples to be used for prediction. After motion-compensating the fetched samples according to the symbols 270 related to the block, these samples may be added by the aggregator 268 to the output of the scaler / inverse unit 258 (in this case, called residual samples or residual signal) to generate output sample information. The address in the reference picture memory 266 from which the motion-compensated prediction unit 260 fetches the predicted samples may be controlled by a motion vector. The motion vector may be available to the motion-compensated prediction unit 260 in the form of a symbol 270 which may have, for example, X, Y, and reference picture components. Motion compensation may also include interpolation of sample values ​​fetched from the reference picture memory 266 when the exact motion vector of a subsample is used, and a motion vector prediction mechanism, etc.

[0049] The output samples of the aggregator 268 can undergo various loop filtering techniques in the loop filter unit 256. The video compression technique may include in-loop filtering techniques controlled by parameters contained in the coded video bitstream and made available to the loop filter unit 256 as symbols 270 from the parser 254, but can respond to previously reconstructed and loop-filtered sample values, as well as metadata obtained during decoding of previous (decoded-order) portions of the coded picture or coded video sequence.

[0050] The output of the loop filter unit 256 can be a sample stream that can be output to a rendering device such as the display 124, or it can be recorded in the reference picture memory 266 for use in future interpicture prediction.

[0051] Once fully reconstructed, a particular coded picture can be used as a reference picture for future predictions. Once a coded picture is fully reconstructed and identified as a reference picture (for example, by parser 254), the current reference picture can become part of the reference picture memory 266 and can be reallocated to a new current picture memory before initiating the reconstruction of subsequent coded pictures.

[0052] The decoder component 122 may perform decoding operations according to a predetermined video compression technique that may be documented in a standard, such as one of the standards described herein. The coded video sequence may conform to the syntax specified in the video compression technique or standard being used, in the sense that it conforms to the syntax of the video compression technique or standard, as specified in the video compression technique documentation or standard, particularly the profile documentation therein. In addition, in order to conform to certain video compression techniques or standards, the complexity of the coded video sequence may be within a range defined by the level of the video compression technique 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 limited by metadata for HRD buffer management and a Hypothetical Reference Decoder (HRD) specification signaled in the coded video sequence.

[0053] Figure 3 is a block diagram showing a server system 112 according to several embodiments. The server system 112 includes a control circuit 302, one or more network interfaces 304, memory 314, a user interface 306, and one or more communication buses 312 for interconnecting these components. In some embodiments, the control circuit 302 includes one or more processors (e.g., CPU, GPU, and / or DPU). In some embodiments, the control circuit includes one or more field-programmable gate arrays (FPGAs), hardware accelerators, and / or one or more integrated circuits (e.g., application-specific integrated circuits).

[0054] The network interface(s) 304 may be configured to interface with one or more communication networks (e.g., wireless, wired, and / or optical networks). These communication networks may be local, wide-area, urban, vehicle, and industrial, real-time, or latency-tolerant. Examples of communication networks include local area networks such as Ethernet and Wi-Fi; cellular networks such as GSM, 3G, 4G, 5G, and LTE; wired or wireless wide-area digital television networks such as cable TV, satellite TV, and terrestrial broadcast TV; and vehicle and industrial networks such as CANBus. Such communications may be one-way, receive-only (e.g., broadcast TV), transmit-only (e.g., CANbus to a specific CANbus device), or bidirectional (e.g., to other computer systems using local or wide-area digital networks). Such communications may include communications to one or more cloud computing networks.

[0055] The user interface 306 includes one or more output devices 308 and / or one or more input devices 310. The input device(s) 310 may include one or more of the following: a keyboard, mouse, trackpad, touchscreen, data glove, joystick, microphone, scanner, camera, etc. The output device(s) 308 may include one or more of the following: an audio output device (e.g., a speaker), a visual output device (e.g., a display or monitor), etc.

[0056] Memory 314 may include high-speed random-access memory (such as DRAM, SRAM, DDR RAM, and / or other random-access solid-state memory devices), and / or non-volatile memory (such as one or more magnetic disk recording devices, optical disk recording devices, flash memory devices, and / or other non-volatile solid-state recording devices). Memory 314 optionally includes one or more recording devices located remotely from the control circuit 302. Memory 314, or the non-volatile solid-state memory devices within Memory 314, includes non-temporary computer-readable recording media. In some embodiments, Memory 314, or the non-temporary computer-readable recording media of Memory 314, may record the following programs, modules, instructions, and data structures, or subsets or supersets thereof: ● Operating System 316, which handles various basic system services and includes procedures for performing hardware-dependent tasks. ● A network communication module 318 used to connect the server system 112 to other computing devices via one or more network interfaces 304 (for example, via wired and / or wireless connections). ● A coding module 320 for performing various functions related to the encoding and / or decoding of data such as video data. In some embodiments, the coding module 320 is an instance of the coder component 114. The coding module 320 includes, but is not limited to, one or more of the following: ● Decoding module 322 for performing various functions related to decoding encoded data, as described above, with respect to decoder component 122. ● Encoding module 340 for performing various functions related to encoded data as described above, with respect to encoder component 106 ● A picture memory 352 for recording pictures and picture data, for use with, for example, a coding module 320. In some embodiments, the picture memory 352 includes one or more of the following: a reference picture memory 208, a buffer memory 252, a current picture memory 264, and a reference picture memory 266.

[0057] In some embodiments, the decoding module 322 includes an analysis module 324 (for example, configured to perform the various functions described above with respect to the parser 254), a transformation module 326 (for example, configured to perform the various functions described above with respect to the scaler / inverse transformation unit 258), a prediction module 328 (for example, configured to perform the various functions described above with respect to the motion compensation prediction unit 260 and / or intrapicture prediction unit 262), and a filter module 330 (for example, configured to perform the various functions described above with respect to the loop filter 256).

[0058] In some embodiments, the coding module 340 includes a code module 342 (for example, configured to perform the various functions described above with respect to the source coder 202 and / or coding engine 212) and a prediction module 344 (for example, configured to perform the various functions described above with respect to the predictor 206). In some embodiments, the decoding module 322 and / or coding module 340 include a subset of the modules shown in Figure 3. For example, a shared prediction module is used by both the decoding module 322 and the coding module 340.

[0059] Each of the identified modules recorded in memory 314 corresponds to a set of instructions for performing the functions described herein. The modules identified above (e.g., sets of instructions) do not need to be implemented as separate software programs, procedures, or modules, and therefore various subsets of these modules may be combined or otherwise rearranged in various embodiments. For example, the coding module 320 uses the same set of modules to perform both sets of functions, rather than optionally including separate decoding and coding modules. In some embodiments, memory 314 records a subset of the modules and data structures identified above. In some embodiments, memory 314 records additional modules and data structures not described above, such as an audio processing module.

[0060] Figure 3 shows server systems 112 according to several embodiments, but Figure 3 is not a schematic diagram of the structure of the embodiments described herein, but is intended to be a functional description of various features that may be present in one or more server systems. In practice, as will also be recognized by those skilled in the art, items shown separately can be combined, and some items can be separated. For example, some items shown separately in Figure 3 can be implemented on a single server, and a single item can be implemented by one or more servers. The actual number of servers used to implement server system 112, and how functions are allocated among them, will vary from implementation to implementation and will optionally depend in part on the amount of data traffic the server system will handle during peak and average usage periods.

[0061] Examples of coding processes and techniques The coding processes and techniques described below may be performed on the devices and systems described above (e.g., source device 102, server system 112, and / or electronic device 120). Figures 4A to 4D show exemplary coding tree structures according to several embodiments. As shown in the first coding tree structure (400) in Figure 4A, some coding techniques (e.g., VP9) use a four-way partition tree starting at the 64x64 level and going down to the 4x4 level, with some additional constraints for the 8x8 block. In Figure 4A, the partition designated as R can be called recursive in that the same partition tree is repeated at lower scales until the lowest 4x4 level is reached.

[0062] As shown in the second coding tree structure (402) in Figure 4B, some coding techniques (e.g., AV1) extend the partition tree to a 10-way structure, increasing the maximum size (e.g., called a superblock in industry jargon for VP9 / AV1) from 128x128. The second coding tree structure includes 4:1 / 1:4 rectangular partitions not present in the first coding tree structure. The partition type with three subpartitions in the second row of Figure 4B is called a T-partition. In addition to the coding block size, the coding tree depth can be defined to indicate the partition depth from the root node.

[0063] As an example, a CTU may be divided into CUs by using a quadtree structure, represented as a coding tree, to adapt to various local characteristics such as HEVC. In some embodiments, the decision of whether to code a picture area using interpicture (time) prediction or intrapicture (spatial) prediction is made at the CU level. Each CU can be further divided into one, two, or four PUs according to the PU division type. Within a single PU, the same prediction process is applied, and relevant information is sent to the decoder on a PU-by-PU basis. After obtaining residual blocks by applying the prediction process based on the PU division type, the CU may be divided into TUs according to another quadtree structure, such as a coding tree for the CU.

[0064] A quadtree with nested multi-type trees using binary and ternary partitioning segments, such as in VVC, can replace the concept of multiple partition unit types, eliminating the separation of the concepts of CU, PU, ​​and TU, except when necessary for CUs that are too large for the maximum transformation length, and supporting greater flexibility in CU partition shapes. In a coding tree structure, a CU can have a square or rectangular shape. A CTU is initially partitioned by a four-element tree (also called a quadtree) structure. The leaf nodes of the four-element tree can be further partitioned by a multi-type tree structure. As shown in the third coding tree structure (404) in Figure 4C, the multi-type tree structure contains four partition types. The leaf nodes of the multi-type tree are called CUs, and this segmentation is used for prediction and transformation processing without further partitioning, as long as the CU is not too large for the maximum transformation length. This means that in most cases, CUs, PUs, and TUs have the same block size in a quadtree with a nested multi-type tree coding block structure. An example of a block partition for one CTU(406) is shown in Figure 4D, which illustrates an exemplary quadtree with a nested multi-type tree coding block structure.

[0065] Motion estimation involves determining a motion vector that describes the transformation from one image (picture) to another. The reference image (or block) can be from neighboring frames in a video sequence. The motion vector may be related to the entire image (global motion estimation) or to a specific block. Furthermore, the motion vector can correspond to a translational model or a warped model that approximates the motion (e.g., rotation and translation in three dimensions, and zoom). The estimated motion can be improved in some situations (e.g., more complex video objects) by further subdividing the block.

[0066] Geometric partitioning modes (GPMs) may focus on interpicture prediction blocks (e.g., CUs). When GPMs are applied to a block, the block is divided into two parts via a straight partition boundary. The position of the partition boundary may be mathematically defined by an angular parameter φ and an offset parameter ρ. These parameters may be quantized and coupled to a lookup table of GPM partitioning indices. Currently, the GPM partitioning indices for a block may be coded into a bitstream. For example, for a CU with size w×h=2k×2l (with respect to luminance samples) where k,l∈{3...6}, the GPMs for VVCs support 64 partitioning modes. For example, since narrow CUs contain few geometrically separated patterns, GPMs may be disabled for CUs with aspect ratios greater than 4:1 or less than 1:4.

[0067] After splitting, the two GPM sections (partitions) now contain individual motion information that can be used to predict the corresponding sections within the block. In some embodiments, only unidirectional motion-compensated predictions (MCPs) are permitted for each section of the GPM, so the memory bandwidth required for MCPs in the GPM is equal to the memory bandwidth required for normal bidirectional MCPs. To simplify motion information coding and reduce the number of possible GPM combinations, the motion information may be coded in merge mode. A GPM merge candidate list can be derived from a conventional merge candidate list to ensure that it contains only unidirectional motion information.

[0068] Figure 5A shows a GPM prediction process according to several embodiments. The current block 510 is divided into a right section and a left section via a partition 516. The right-hand prediction portion of the current block 510 (e.g., size w x h) of the current picture 502 (e.g., CU) is predicted by MV0 from reference block 512 of reference picture 504, and the left-hand portion is predicted by MV1 from reference block 514 of reference picture 506.

[0069] Figure 5B shows exemplary blend matrices for partitions (e.g., partition 516) according to several embodiments. In this example, the final GPM prediction (PG) is generated by performing a blending process using integer blend matrices W0 and W1 containing weights in the range of values ​​from 0 to 8, for example. This can be expressed as follows:

[0070]

number

[0071] In Equation 1, J is a matrix of size w × h. The weights of the blend matrix may depend on the displacement between the sample position and the partition boundary. Since the computational complexity of deriving the blend matrix can be reduced, these matrices can be generated on the decoder side, on the fly.

[0072] Next, the generated GPM prediction (PG) can be subtracted from the original signal to produce the residual. The residual may be converted to a bitstream, quantized, and coded using, for example, a standard VVC transform, quantization, and entropy coding engine. On the decoder side, the signal is reconstructed by adding the residual to the GPM prediction PG. A skip mode can also be supported by the GPM, for example, when the residual is negligible. For example, the residual is dropped by the encoder, and the GPM prediction PG is used directly by the decoder as the reconstructed signal.

[0073] GPM can be further enhanced by, for example, GPM+TM (bidirectional matching), GPM+MMVD (merge mode with motion vector difference), and inter+intraGPM. As shown in Figure 5C, the blend intensity or blend region width θ may be fixed for all different contents. In some embodiments, the metric values ​​in the blend mask are given by a ramp function.

[0074]

number

[0075] For example, consider a fixed θ=2 pixel. This ramp function can be quantized as follows:

[0076]

number

[0077] Such a design may not always be optimal, as a fixed blend area width does not always provide the best blend quality for various types of video content. For example, video content typically contains strong textures and sharp edges, requiring a narrow blend area to preserve edge information. Camera-captured content generally requires blending, but the blend area width can depend on several factors, such as the actual boundaries of moving objects and the distinguishability of the movement of two partitions.

[0078] To address this issue, an adaptive blending scheme can be used in the GPM that dynamically adjusts the width of the blend region surrounding the GPM partition boundary. For example, the blend region width (θ) can be selected from a set of predetermined values ​​{0, 1, 2, 4, 8}. The optimal blend region width can be determined for each GPM block in the encoder and signaled to the decoder based on a syntax element, such as merge_gpm_blending_width_idx. As an example, all clipping and shifting operations in the GPM blending process may be maintained unchanged, while all predefined blend intensity values ​​may be shiftable.

[0079] Furthermore, to accommodate the increased width of the GPM blend region, the weight range may be increased from [0,8] to [0,32]. Specifically, the weights can be calculated as follows:

[0080]

number

[0081] Wedge-based prediction is a composite prediction mode (e.g., in AV1) that is similar to GPM. Wedge-based prediction can be used in both inter-inter and inter-intra combinations. The boundaries of moving objects are often difficult to approximate by block partitions on a grid. The solution is to predefine a codebook of possible wedge partitions (e.g., 16) and signal wedge indices in the bitstream when coding units are further divided in that manner. The current wedge design in AV1 supports 16 modes because up to 16 symbols can be signaled in a single syntax element using the multi-symbol adaptive context coding used in AV1. The 16-element shape codebook, including any of the partition directions of horizontal, vertical, and diagonal (e.g., tilt ±2 or ±0.5), is designed for both square blocks 540 and rectangular blocks 542, as shown in Figure 5D. To mitigate spurious 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 intended partition (e.g., m(i,j) is close to 0.5 around the edge and gradually transforms to binary weights at both ends).

[0082] The inter-intra prediction mode is a composite prediction mode that combines an inter-predictor and an intra-predictor. The inter-predictor in the inter-intra mode may be generated using a single predictor, as described elsewhere in this specification. 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 together in either a smooth inter-intra mode or a wedge inter-intra mode. In the case of a wedge inter-intra mode, the inter-predictor and intra-predictor may be combined together using a wedge mask. In the case of a smooth inter-intra mode, the mask used to combine the inter-predictor and intra-predictor may depend on the intra-mode. Examples of normalized mask weights for the vertical (vertical mask 552), horizontal (horizontal mask 554), smooth (smooth mask 556), and DC (DC mask 558) modes are shown in Figure 5E.

[0083] The wedge modes in AV1 described above may be extended to accommodate wedge modes used for 64x64, 32x64, 64x32, 16x64, and 64x16 blocks. Furthermore, the wedge modes may be defined in Hessian standard 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 may be quantized to a value (e.g., 20 values) using the tangent value. The distance may be quantized based on the block size. For example, three distances may be used for angles greater than 180 degrees, and for angles of 0 or 90 degrees. For other angles, four distances may be used. In this way, 8 × 4 + 12 × 3 = 68 modes can be supported. Since more than 16 modes are supported, the wedge index may be signaled with three syntactic elements, for example, 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 may be signaled. The distance may be signaled according to the signaled angle.

[0084] The wedge blend mask may be quantized directly from the distance between the sample position and the partition boundary. Using a partition boundary definition in Hessian standard form, the distance can be defined as follows:

[0085]

number

[0086] Here, ρ is the distance from the center and φ is the partition angle. The angle and distance may be quantized using the tangent value and block size. Thus, only a lookup table and shift operation may be required to compute the quantized d(m, n) as shown in Equation 6 below.

[0087]

number

[0088] The blend weights at the corresponding locations can be derived using Equation 7.

[0089]

number

[0090] Blend weights may be calculated on the fly (for example, due to their low computational complexity) or they may be pre-recorded (for example, as in AV1 wedge mode design).

[0091] In some systems, wedge inter-intra mode and smooth inter-intra mode (SIIP) share the same hardcoded intra-modes, such as DC intra-mode, vertical intra-mode, horizontal intra-mode, and smooth inter-intra mode. However, using a fixed set of intra-modes can reduce coding efficiency and / or may include modes unsuitable for certain blocks. The methods and processes described below incorporate an adaptive intra-mode list (e.g., wedge inter-intra mode and / or smooth inter-intra mode) to improve coding efficiency and / or reduce transmission bandwidth.

[0092] Figure 6A is a flowchart illustrating a method 600 for encoding video according to several embodiments. The method 600 can be performed in a computing system (e.g., a server system 112, a source device 102, or an electronic device 120) having a control circuit and a memory for recording instructions for execution by the control circuit. In some embodiments, the method 600 is performed by executing instructions recorded in the memory of the computing system (e.g., memory 314).

[0093] The system receives video data containing multiple blocks, including a first block containing a first partition and a second partition (602), the first block to be encoded with inter-intra prediction, the first partition to be predicted with intra prediction, and the second partition to be predicted with inter-prediction mode. The system generates a list of candidate intra-modes for the first partition (604). The system selects an intra-prediction mode from the list of candidate intra-prediction modes to predict the first partition (606). The system encodes the first block using the intra-prediction corresponding to the intra-prediction mode selected for the first partition and the inter-prediction for the second partition (608). For example, an intra-mode list is constructed for the first block, and this intra-mode list is used in the intra-mode prediction section of an inter-intra mode (e.g., wedge inter-intra mode or smooth inter-intra mode).

[0094] Figure 6B is a flowchart illustrating a method 650 for decoding video according to several embodiments. The method 650 can be performed in a computing system (e.g., a server system 112, a source device 102, or an electronic device 120) having a control circuit and a memory for recording instructions for execution by the control circuit. In some embodiments, the method 650 is performed by executing instructions recorded in the memory of the computing system (e.g., memory 314).

[0095] The system receives video data from a video bitstream, which includes a first block containing a first partition and a second partition (652), the first block being encoded with inter-intra prediction, the first partition being predicted in intra-prediction mode, and the second partition being predicted in inter-prediction mode. The system generates a list of candidate intra-prediction modes for the first partition (654). The system selects an intra-prediction mode from the list of candidate intra-prediction modes to predict the first partition (656). The system decodes the first block using the intra-prediction corresponding to the selected intra-prediction mode for the first partition and the inter-prediction for the second partition (658).

[0096] Figures 6A and 6B show several logical stages in a specific order, but the order-independent stages may be rearranged, and the other stages may be combined or separated. Several rearrangements or other groupings not specifically mentioned will be obvious to those skilled in the art, and therefore the rearrangements and groupings presented herein are not exhaustive. Furthermore, it should be noted that the stages can be implemented in hardware, firmware, software, or any combination thereof.

[0097] The systems described herein can be used for GPM or wedge-based partitioning. In some embodiments, an intra-mode list is constructed for the current block encoded with inter-intra prediction. The intra-mode list is used for intra-mode prediction of wedge inter-intra prediction or smooth inter-intra prediction. The size of this intra-mode list may be represented as N and may be predefined or signaled with high-level syntax. For example, N may be a positive integer such as 4 or 6. In some embodiments, multiple predefined values ​​of N are supported, and the selection of a predefined value is signaled at the sequence, frame, slice, or tile level. Specifically, the current block may include a first partition and a second partition. The first partition is predicted in intra-prediction mode, and the second partition is predicted in inter-prediction mode. The disclosed method can generate a list of candidate intra-prediction modes for the first partition, the list having size N, where N is a positive integer. Furthermore, the disclosed method can select an intra-prediction mode from a list of candidate intra-prediction modes for predicting the first partition, and decode the first block using the intra-prediction for the first partition and the inter-prediction for the second partition.

[0098] In some embodiments, the intra-mode list for wedge inter-intra prediction or smooth inter-intra prediction is adaptively generated using predefined modes and intra-modes of adjacent blocks. In some embodiments, the index of the best intra-mode is signaled within the bitstream.

[0099] In some embodiments, the intra-mode list contains up to N=6 candidates. The intra-mode list may contain one or more of the following intra-modes: smooth mode, vertical mode, intra-mode from the left neighboring block, intra-mode from the upper neighboring block, horizontal mode, DC mode, smooth horizontal mode, and smooth vertical mode. In some embodiments, the value of N depends on how many neighboring blocks (or pixels) are coded by the intra (or inter) prediction mode. In some embodiments, the order for inserting predefined intra-prediction modes and neighboring block intra-prediction modes depends on the block size and / or shape of the current block. In some embodiments, the order of intra-prediction modes in the list is adaptively determined based on the accuracy of the intra-prediction modes on neighboring reconstructed samples (determined, for example, by template matching).

[0100] As an example, intra-mode candidates are pruned and inserted into the list until the list is full. In some embodiments, smooth mode and vertical mode are inserted into the list. Then, adjacent block intra-modes up to M=4 are pruned and inserted into the list. In some embodiments, the adjacent block scan order is predefined. In various embodiments, the value of M is predefined or signaled by high-level syntax. Then, horizontal mode, DC mode, smooth horizontal mode, and smooth vertical mode are pruned and inserted until the list is full.

[0101] As another example, smooth mode and vertical mode are inserted into the list. Then, adjacent block intra modes with a maximum M=1 are pruned and inserted into the list. In this example, if an adjacent block uses an angle mode, the two angle modes closest to the adjacent block's angle mode are also inserted. Then, horizontal mode, DC mode, smooth horizontal mode, and smooth vertical mode are pruned and inserted until the list is full.

[0102] In some embodiments, more distant neighboring reconstruction samples are used to predict closer neighboring reconstruction samples for the current block based on the intra-prediction mode in the list. For example, the intra-prediction mode that produces the smallest sum of absolute differences (SAD) and / or sum of absolute transformed differences (SATD) is selected as the best intra-prediction mode.

[0103] In some embodiments, the smooth inter-intra uses a fixed set of modes, while the intra-mode list is generated for the wedge inter-intra modes. For example, the wedge inter-intra list is generated adaptively using the intra-modes and / or wedge modes (e.g., wedge angles) of adjacent blocks. As an example, the intra-mode list may contain up to N=4 candidates. In this example, the smooth mode and vertical mode are inserted into the list. Then, the angle mode parallel and perpendicular to the wedge partition boundary is inserted into the list.

[0104] As another example, the intra-mode list contains up to N=4 candidates. In this example, the smooth mode and vertical mode are inserted into the list. Then, the angle mode parallel to the wedge partition boundary is inserted into the list. Next, the angle mode closest to the previously inserted angle mode is inserted into the list.

[0105] As another example, the intra-mode list may contain up to N=6 candidates. In this example, the smooth mode and vertical mode are inserted into the list. Then, the intra-modes of the left- and top-neighboring blocks are pruned and inserted into the list. Next, the angle mode, which is parallel and perpendicular to the wedge partition boundary, is inserted into the list.

[0106] In some embodiments, if the partition boundary of a wedge mode forms an intra-prediction portion that does not overlap with a predefined block boundary (such as the top and left block boundaries), that wedge mode is not permitted for wedge-inter-intra-prediction. For example, in some current systems, angles greater than 270 degrees generate intra-predictors that do not overlap with the left and top boundaries of the current block. In this example, these angles are excluded from the intra-mode list (e.g., not used for wedge-inter-intra-prediction).

[0107] (A1) In one embodiment, several embodiments include a method for video encoding (e.g., method 600). In some embodiments, the method is performed on a computing system having memory and control circuits (e.g., server system 112). In some embodiments, the method is performed on a coding module (e.g., coding module 320). In some embodiments, the method is performed on a source coder 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 comprising a plurality of blocks, including a first block comprising a first partition and a second partition, wherein the first block is encoded in inter-intra prediction mode, the first partition is predicted in intra prediction mode, and the second partition is predicted in inter prediction mode; (ii) generating a list of candidate intra prediction modes for the first partition, the list having size N, where N is a positive integer; (iii) selecting an intra prediction mode from the list of candidate intra prediction modes to predict the first partition; and (iv) decoding the first block using the intra prediction corresponding to the selected intra prediction mode for the first partition and the inter prediction for the second partition. In some embodiments, the size of the list of candidate intra prediction modes is predefined. In some embodiments, the candidate list of intra prediction modes for the first block is generated based on an insertion order, the insertion order based on the block shape of the first block, the size of the first block, and / or the accuracy of each intra prediction mode on adjacent reconstructed samples. In some embodiments, the first block is encoded with partition-based inter-intra prediction, and the list of intra-prediction modes is generated based on one or more partition modes.

[0108] (A2) In some embodiments of A1, the method further includes transmitting an encoded first block over a video bitstream. In some embodiments, the method further includes signaling an index of a selected intra-prediction mode in the video bitstream. In some embodiments, the method further includes signaling the size of a list of candidate intra-prediction modes via a syntax element in the video bitstream.

[0109] (A3) In some embodiments of A1 or A2, the list of candidate intra-prediction modes is generated based on the intra-modes of one or more adjacent blocks of the first block.

[0110] (A4) In some embodiments of A1 to A3, one or more intra-prediction modes in the list of candidate intra-prediction modes are selected from the group consisting of smooth intra-mode, vertical intra-mode, intra-mode used for the left adjacent block, intra-mode used for the upper adjacent block, horizontal intra-mode, DC intra-mode, smooth horizontal intra-mode, and smooth vertical intra-mode.

[0111] (A5) In some embodiments of A1 to A4, generating a list of candidate intra-prediction modes includes (i) inserting smooth intra-prediction modes into the list of candidate intra-prediction modes, (ii) inserting vertical intra-modes into the list of candidate intra-prediction modes, and (iii) inserting a set of adjacent block intra-prediction modes into the list of candidate intra-prediction modes.

[0112] (A6) In some embodiments of A5, the set of intra-modes for adjacent blocks includes adjacent block angle modes, and generating a list of candidate intra-prediction modes further includes inserting an additional set of angle modes based on the adjacent block angle modes.

[0113] (A7) In some embodiments of A1 to A6, the method further includes determining the size of a list of candidate intra-prediction modes based on the number of adjacent blocks coded in the intra-prediction mode.

[0114] (B1) In other embodiments, some embodiments include a method for video decoding (e.g., method 650). In some embodiments, the method is performed in a computing system having memory and control circuits (e.g., server system 112). 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 compensation 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, which includes a first block containing a first partition and a second partition, and the first block being coded with inter-intra prediction, the first partition being predicted in intra-prediction mode, and the second partition being predicted in inter-prediction mode; (ii) generating a list of candidate intra-prediction modes for the first partition, the list having size N, where N is a positive integer; (iii) selecting an intra-prediction mode from the list of candidate intra-prediction modes to predict the first partition; and (iv) decoding the first block using the intra-prediction corresponding to the selected intra-prediction mode for the first partition and the inter-prediction for the second partition. For example, the intra-mode list is reconstructed for the first block, which is used for intra-mode prediction of wedge inter-intra mode or smooth inter-intra mode.

[0115] (B2) In some embodiments of B1, the list of candidate intra-prediction modes is generated based on the intra-modes of one or more adjacent blocks of the first block. For example, the list of intra-modes for wedge intra-mode or smooth intra-prediction is adaptively generated using a predetermined mode and / or intra-mode from one of the adjacent blocks.

[0116] (B3) In some embodiments of B1 or B2, one or more intra-prediction modes in the list of candidate intra-prediction modes are selected from the group consisting of smooth intra-mode, vertical intra-mode, intra-mode used for the left adjacent block, intra-mode used for the upper adjacent block, horizontal intra-mode, DC intra-mode, smooth horizontal intra-mode, and smooth vertical intra-mode. For example, up to N=6 candidates are supported for the intra-prediction mode list. The list may include one or more of the following intra-modes: smooth mode, vertical mode, intra-mode from the left adjacent block, intra-mode from the upper adjacent block, horizontal mode, DC mode, smooth horizontal mode, and smooth vertical mode. Candidate intra-modes may be pruned and inserted into the list until the list is full.

[0117] (B4) In some embodiments of B1 to B3, generating a list of candidate intra-prediction modes includes (i) inserting smooth intra-prediction modes into the list of candidate intra-prediction modes, (ii) inserting vertical intra-modes into the list of candidate intra-prediction modes, and (iii) inserting a set of adjacent block intra-prediction modes into the list of candidate intra-prediction modes. For example, if the list is of size N=6, smooth modes and vertical modes are inserted into the list, and up to M=4 adjacent block intra-modes are pruned and inserted into the list. In some embodiments, the adjacent block scan order is predefined. In various embodiments, the value of M is predefined or signaled by high-level syntax. In some embodiments, after inserting the set of adjacent block intra-modes, horizontal modes, DC modes, smooth horizontal modes, and / or smooth vertical modes are inserted until the list is full.

[0118] In some embodiments of (B5)B4, the set of intra-modes for adjacent blocks includes adjacent block angle modes, and generating a list of candidate intra-predicted modes further includes inserting an additional set of angle modes based on the adjacent block angle modes. For example, if an adjacent block uses an angle mode, the two closest angle modes of this adjacent block's intra-modes are also inserted into the list. In some embodiments, after inserting the additional set of angle modes, horizontal, DC, smooth horizontal, and / or smooth vertical modes are inserted until the list is full.

[0119] (B6) In some embodiments of B1 to B5, the index of the selected intra-prediction mode is signaled in the video bitstream. For example, the index of the best intra-mode is signaled in the bitstream.

[0120] (B7) In some embodiments of B1 to B6, the method further includes identifying the size of a list of candidate intra-predictive modes based on syntax elements in the video bitstream. For example, multiple predefined values ​​of N are supported, and the selection of a predefined value is signaled at the sequence, frame, slice, or tile level. As an example, the size of the intra-mode list is N, which is predefined or signaled by 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. The high-level syntax may include a video parameter set (VPS), a sequence parameter set (SPS), a picture parameter set (PPS), an adaptive parameter set (APS), a slice header, a picture header, a tile header, and / or a CTU header.

[0121] (B8) In some embodiments of B1 to B7, the method further includes determining the size of a list of candidate intra-prediction modes based on the number of adjacent blocks coded in the intra-prediction mode. For example, the value of N depends on how many adjacent blocks (or pixels) are coded by the intra (or inter) prediction mode.

[0122] (B9) In some embodiments of B1 to B8, the size of the list of candidate intra-prediction modes is predefined. For example, high-level syntax corresponds to sequence level, frame level, slice level, or tile level. As another example, N is a positive integer such as 4 or 6.

[0123] (B10) In some embodiments of B1 to B9, the list of candidate intra-prediction modes for the first block is generated based on the insertion order, which is based on the block shape and / or size of the first block. For example, the order in which predefined intra-prediction modes and adjacent block intra-prediction modes are inserted depends on the block size / shape of the current block.

[0124] (B11) In some embodiments of B1 to B9, the list of candidate intra-prediction modes for the first block is generated based on an insertion order, which is based on the accuracy of each intra-prediction mode in the set of intra-prediction modes on adjacent reconstructed samples. For example, the order of the intra-prediction modes in the list is determined adaptively based on the accuracy of the intra-prediction modes on adjacent reconstructed samples. In some embodiments, the accuracy of each intra-prediction mode is based on the sum of absolute differences (SAD) or the sum of absolute transformation differences (SATD). For example, the intra-prediction mode with the smallest SAD / SATD value is selected as the best intra-prediction mode. In some embodiments, further-distant adjacent reconstructed samples are used to predict closer adjacent reconstructed samples of the current block based on the intra-prediction modes in the list.

[0125] (B12) In some embodiments of B1 to B11, the first block is encoded with partition-based inter-intra prediction, and a list of candidate intra-prediction modes is generated based on one or more partition modes. For example, smooth intra uses a fixed mode or a predefined list, while wedge inter-intra generates an intra-mode list. In some embodiments, the wedge inter-intra list is generated adaptively using the intra-modes and / or wedge modes (e.g., wedge angles) of adjacent blocks.

[0126] (B13) In some embodiments of B12, the method further includes identifying partition boundaries of a first block based on partition-based inter-intra prediction, and generating a list of intra candidate prediction modes includes at least one of (i) inserting a first angular mode parallel to the partition boundary of the first block, and (ii) inserting a second angular mode perpendicular to the partition boundary of the first block. For example, a smooth mode and a perpendicular mode are inserted, and then angular modes parallel and perpendicular to the wedge partition boundary are inserted into the list. Another example is that an angular mode parallel to the wedge partition boundary is inserted into the list, and then the angular mode closest to a previously inserted angular mode is inserted into the list. Another example is that a smooth mode and a perpendicular mode are inserted, and then the left- and top-next-block intra modes are pruned and inserted into the list, and then angular modes parallel and perpendicular to the wedge partition boundary are inserted into the list.

[0127] (B14) In some embodiments of B12 or B13, the method further includes excluding each partition mode in a set of partition modes from being inserted into a list of candidate intra-prediction modes, based on the determination that the corresponding partition boundary results in an intra-prediction that does not overlap with one or more predefined block boundaries. For example, if the partition boundary of a wedge mode forms an intra-prediction portion that does not overlap with predefined block boundaries (such as the top and left block boundaries), then this wedge mode cannot be used for wedge-inter-intra-prediction. As an example, angles greater than 270 degrees can generate intra-predictors that do not overlap with the left and top boundaries of the current block, and therefore these angles are not used for wedge-inter-intra-prediction.

[0128] In another embodiment, some embodiments include a computing system (e.g., server system 112) which includes a control circuit (e.g., control circuit 302) and a memory coupled to the control circuit (e.g., memory 314), the memory which stores one or more instruction sets configured to be executed by the control circuit, the one or more instruction sets which include instructions for executing any of the methods described herein (e.g., A1 to A7 and B1 to B14 above).

[0129] In yet another embodiment, some embodiments include a non-temporary computer-readable recording medium for recording one or more instruction sets for execution by a control circuit of a computing system, the one or more instruction sets including instructions for executing any of the methods described herein (e.g., A1-A7 and B1-B14 above).

[0130] In this specification, various elements may be described using terms such as "first" and "second," but it should be understood that these elements should not be limited by these terms. These terms are used solely to distinguish one element from another.

[0131] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the claims. As used in the descriptions of embodiments and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural form unless the context clearly indicates otherwise. The terms “and / or” as used herein will be understood to refer to and encompass one or any possible combination of the related enumerated items. The terms “comprises” and / or “comprising,” as used herein, specify the presence of the described features, integers, steps, actions, elements, and / or components, but will not preclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.

[0132] As used herein, the term “if” may, depending on the context, be interpreted as “when” or “upon” or “in response to determining” or “in accordance with a determination” or “in response to detecting” that the stated condition is true. Similarly, the phrases "[if it is determined that the stated condition is true]" or "[if the stated condition is true]" or "[if the stated condition is true]" may, depending on the context, be interpreted as “when it is determined” or “in response to having determined” or “in accordance with a determination” or “when it is detected” or “in response to having detected” that the stated condition is true.

[0133] The above description is provided with reference to specific embodiments for illustrative purposes. However, the above exemplary description is not intended to be exhaustive or to limit the claims to the exact form disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments have been selected and described to best illustrate the operating principle and practical applications, thereby enabling others skilled in the art.

Claims

1. A video decoding method performed on a computing system having memory and one or more processors, Receiving video data from a video bitstream, which includes a plurality of blocks, including a first block containing a first partition and a second partition, wherein the first block is encoded in inter-intra prediction mode, the first partition is predicted in intra prediction mode, and the second partition is predicted in inter prediction mode. To generate a list of candidate intra-prediction modes for the first partition, the list having size N, where N is a positive integer, Selecting an intra prediction mode from the list of candidate intra prediction modes in order to predict the first partition, Decoding the first block using the intra-prediction corresponding to the selected intra-prediction mode for the first partition and the inter-prediction for the second partition, including, How to decrypt video.

2. The list of candidate intra-prediction modes is generated based on the intra-modes of one or more adjacent blocks of the first block. The method according to claim 1.

3. One or more intra-prediction modes from the list of candidate intra-prediction modes are selected from the group consisting of smooth intra-mode, vertical intra-mode, intra-mode used for the left adjacent block, intra-mode used for the upper adjacent block, horizontal intra-mode, DC intra-mode, smooth horizontal intra-mode, and smooth vertical intra-mode. The method according to claim 1.

4. Generating the list of candidate intra-prediction modes is: Insert the smooth intra mode into the list of candidate intra prediction modes, Insert the vertical intra mode into the list of candidate intra prediction modes, Inserting a set of adjacent block intra modes into the list of candidate intra-prediction modes, including, The method according to claim 1.

5. The set of adjacent block intra modes includes adjacent block angular modes, Generating the list of candidate intra-prediction modes further includes inserting an additional set of angle modes based on the adjacent block angle modes. The method according to claim 4.

6. The index of the selected intra prediction mode is signaled within the video bitstream. The method according to claim 1.

7. The further includes identifying the size of the list of candidate intra-prediction modes based on syntax elements within the video bitstream, The method according to claim 1.

8. The further includes determining the size of the list of candidate intra-prediction modes based on the number of adjacent blocks coded in the intra-prediction mode, The method according to claim 1.

9. The size of the list of candidate intra prediction modes is predefined. The method according to claim 1.

10. A list of intra-prediction modes for the first block is generated based on the insertion order, and the insertion order is based on the block shape and / or size of the first block. The method according to claim 1.

11. A list of intra-prediction modes for the first block is generated based on the insertion order, the insertion order being based on the respective accuracy of each intra-prediction mode in the set of intra-prediction modes on adjacent reconstructed samples. The method according to claim 1.

12. The first block described above is encoded with partition-based inter-intra prediction, The list of candidate intra-prediction modes is generated based on one or more partition modes. The method according to claim 1.

13. The method further includes identifying the partition boundaries of the first block based on the partition-based inter-intra prediction mode, Generating the list of candidate intra-prediction modes includes at least one of (i) inserting a first angular mode parallel to the partition boundary of the first block, and (ii) inserting a second angular mode perpendicular to the partition boundary of the first block. The method according to claim 12.

14. For each partition mode in the set of partition modes, the partition mode is further excluded from being inserted into the list of candidate intra-prediction modes based on the determination that the corresponding partition boundary results in an intra-prediction that does not overlap with one or more predefined block boundaries. The method according to claim 12.

15. Control circuit and Memory and The system comprises one or more instruction sets, which are recorded in the memory and configured for execution by the control circuit, and the one or more instruction sets are Receiving video data from a video bitstream, which includes a plurality of blocks, including a first block containing a first partition and a second partition, wherein the first block is encoded in inter-intra prediction mode, the first partition is predicted in intra prediction mode, and the second partition is predicted in inter prediction mode. To generate a list of candidate intra-prediction modes for the first partition, the list having size N, where N is a positive integer, Selecting an intra-prediction mode from a list of candidate intra-prediction modes in order to predict the first partition, Decoding the first block using the intra-prediction corresponding to the selected intra-prediction mode for the first partition and the inter-prediction for the second partition. Includes instructions for, Computing system.

16. The list of candidate intra-prediction modes is generated based on the intra-modes of one or more adjacent blocks of the first block. The computing system according to claim 15.

17. One or more intra-prediction modes from the list of candidate intra-prediction modes are selected from the group consisting of smooth intra-mode, vertical intra-mode, intra-mode used for the left adjacent block, intra-mode used for the upper adjacent block, horizontal intra-mode, DC intra-mode, smooth horizontal intra-mode, and smooth vertical intra-mode. The computing system according to claim 15.

18. Generating the list of candidate intra-prediction modes is: Insert the smooth intra mode into the list of candidate intra prediction modes, Insert the vertical intra mode into the list of candidate intra prediction modes, Inserting a set of adjacent block intra modes into the list of candidate intra-prediction modes, including, The computing system according to claim 15.

19. A non-temporary computer-readable recording medium for recording one or more instruction sets configured to be executed by a computing device having a control circuit and memory, wherein the one or more instruction sets are Receiving video data from a video bitstream, which includes a plurality of blocks, including a first block containing a first partition and a second partition, wherein the first block is encoded in inter-intra prediction mode, the first partition is predicted in intra prediction mode, and the second partition is predicted in inter prediction mode. To generate a list of candidate intra-prediction modes for the first partition, the list having size N, where N is a positive integer, Selecting an intra-prediction mode from a list of candidate intra-prediction modes in order to predict the first partition, Decoding the first block using the intra-prediction corresponding to the selected intra-prediction mode for the first partition and the inter-prediction for the second partition. Includes instructions for, Non-temporary computer-readable recording medium.

20. The list of candidate intra-prediction modes is generated based on the intra-modes of one or more adjacent blocks of the first block. The non-temporary computer-readable recording medium according to claim 19.

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