KR20230162614A - Adaptive coding of motion information for multi-hypothesis prediction for video coding. - Google Patents

Abstract

An example device for decoding video data includes one or more processors, the one or more processors configured to: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block indicating an additional prediction hypothesis, wherein the merge mode syntax element indicates whether motion information for the second prediction block is coded using merge mode. Code the elements; Coding motion information for a second prediction block according to a merge mode syntax element, wherein to code the motion information, the one or more processors generate a merge candidate list comprising merge candidates representing respective sets of one-way prediction motion information. coding the motion information, configured to form; generate a second prediction block for the current block of video data using the motion information; form a multi-hypothesis prediction block from the first and second prediction blocks; and is configured to decode the current block using the multi-hypothesis prediction block.

Description

Adaptive coding of motion information for multi-hypothesis prediction for video coding.

This application claims priority to U.S. Patent Application No. 17/655,919, filed March 22, 2022, and U.S. Provisional Application No. 63/167,480, filed March 29, 2021, the entire contents of each of which are incorporated herein by reference. Incorporated by reference. U.S. Patent Application No. 17/655,919, filed March 22, 2022, claims the benefit of U.S. Provisional Application No. 63/167,480, filed March 29, 2021.

technology field

This disclosure relates to video coding, including video encoding and video decoding.

Digital video capabilities include digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, A wide range of devices including digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite wireless phones, so-called “smart phones,” video teleconferencing devices, video streaming devices, etc. can be integrated into Digital video devices support MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4, Part 10, Advanced Video Coding (AVC), and ITU-T H.265/High Efficiency Video Coding. (HEVC), the standards defined by ITU-T H.266/Versatile Video Coding (VVC), and extensions of these standards, as well as AOMedia Video 1 developed by the Alliance for Open Media. Implements video coding techniques such as those described in proprietary video codecs/formats such as (AV1). Video devices may transmit, receive, encode, decode, and/or store digital video information more efficiently by implementing such video coding techniques.

Video coding techniques include spatial (intra-picture) prediction and/or temporal (inter-picture) prediction to reduce or eliminate redundancy inherent in video sequences. For block-based video coding, a video slice (e.g., a video picture or a portion of a video picture) is a video block, which may also be referred to as coding tree units (CTUs), coding units (CUs), and/or coding nodes. It can also be partitioned into fields. Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction with respect to reference samples of neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction relative to reference samples of neighboring blocks in the same picture or temporal prediction relative to reference samples in other reference pictures. Pictures may be referred to as frames, and reference pictures may be referred to as reference frames.

In general, this disclosure describes techniques for multiple hypothesis inter-prediction during video coding. Video coding generally involves partitioning pictures in a series of pictures into individual blocks, and then coding (encoding or decoding) each of the blocks. Coding a block generally involves predicting the block and coding the residuals for the block, i.e. the set of differences between the predicted block and the actual block. Prediction can be intra-picture (i.e., predicting the current block using data from a picture containing the block) or inter-picture (i.e., predicting the current block using data from one or more previously coded pictures). there is. Multi-hypothesis inter prediction refers to using multiple reference blocks from one or more previously coded pictures to predict the current block. For example, a video coder may generate two or more prediction blocks and then combine the values of the prediction blocks using averaging, weighted prediction, etc.

Inter prediction may be signaled using various coding modes, such as merge mode or advanced motion vector prediction (AMVP) mode. Generally, in merge mode, the motion information of the signaled neighboring block is used as the motion information of the current block, while in AMVP mode, the motion information of the signaled neighboring block is used to predict the motion vector of the current block, and the motion information of the current block is used to predict the motion vector of the current block. Other motion information (eg, motion vector difference values and reference picture identification information) is coded to form information. This disclosure describes, among other things, various examples of techniques related to signaling multi-hypothesis inter prediction information using merge mode.

In one example, a method of decoding video data includes generating a first prediction block for a current block of video data using a base inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. coding the merge mode syntax element, indicating whether it is coded; Coding motion information for a second prediction block according to a merge mode syntax element, wherein the motion information for the second prediction block is encoded in a merge mode syntax element. When indicating that it is coded using , forming a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of uni-prediction motion information. Coding motion information for a prediction block; generating a second prediction block for the current block of video data using motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

In another example, a device for decoding video data includes a memory configured to store video data; and one or more processors implemented in circuitry, wherein the one or more processors: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element is such that motion information for the second prediction block is coded using merge mode. code the merge mode syntax element to indicate whether to do so; coding motion information for a second prediction block according to a merge mode syntax element, wherein, to code the motion information, the one or more processors are configured to configure the merge mode syntax element to cause the motion information for the second prediction block to use merge mode. coding the motion information, when indicating that it is coded, configured to form a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information; generate a second prediction block for the current block of video data using the motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and is configured to decode the current block using the multi-hypothesis prediction block.

In another example, instructions are stored on a computer-readable storage medium that, when executed, cause a processor to: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. code the merge mode syntax element, indicating whether to code; By coding the motion information for the second prediction block according to the merge mode syntax element, coding the motion information for the second prediction block means that the merge mode syntax element causes the motion information for the second prediction block to be in merge mode. When indicating that it is coded using, forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information, motion information for the second prediction block. Let them code; generate a second prediction block for the current block of video data using the motion information; form a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; Then, the current block is decoded using a multi-hypothesis prediction block.

In another example, a device for decoding video data includes means for generating a first prediction block for a current block of video data using a basic inter prediction mode; As a means for coding a merge mode syntax element for a second prediction block, the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. means for coding the merge mode syntax element, indicating whether the merge mode syntax element is coded; Means for coding motion information for a second prediction block according to a merge mode syntax element, wherein the merge mode syntax element includes motion information for the second prediction block. When indicating that it is coded using a merge mode, means for forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. means for coding motion information for; means for generating a second prediction block for a current block of video data using motion information; means for forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and means for decoding the current block using the multi-hypothesis prediction block.

Details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects and advantages will become apparent from the description, drawings, and claims.

1 is a block diagram illustrating an example video encoding and decoding system that may perform the techniques of this disclosure.
2 is a conceptual diagram illustrating a table representing an example scheme for one-way predictive motion vector selection for geometric partitioning mode (GPM).
3 is a block diagram illustrating an example video encoder that may perform the techniques of this disclosure.
4 is a block diagram illustrating an example video decoder that may perform the techniques of this disclosure.
5 is a flowchart illustrating an example method for encoding a current block in accordance with the techniques of this disclosure.
6 is a flow chart illustrating an example method for decoding a current block in accordance with the techniques of this disclosure.
7 is a flow chart illustrating an example method of decoding video data according to the techniques of this disclosure.

Video coding generally involves partitioning the pictures in a series of pictures into individual blocks, and then coding (encoding or decoding) each of the blocks. Coding a block generally involves predicting the block and coding the residuals for the block, i.e. the set of differences between the predicted block and the actual block. Prediction can be intra-picture (i.e., predicting the current block using data from a picture containing the block) or inter-picture (i.e., predicting the current block using data from one or more previously coded pictures). there is. Multi-hypothesis inter prediction refers to using multiple reference blocks from one or more previously coded pictures to predict the current block. For example, a video coder may generate two or more prediction blocks and then combine the values of the prediction blocks using averaging, weighted prediction, etc.

Inter prediction may be signaled using various coding modes, such as merge mode or advanced motion vector prediction (AMVP) mode. Generally, in merge mode, the motion information of the signaled neighboring block is used as the motion information of the current block, while in AMVP mode, the motion information of the signaled neighboring block is used to predict the motion vector of the current block, and the motion information of the current block is used to predict the motion vector of the current block. Other motion information (eg, motion vector difference values and reference picture identification information) is coded to form information.

This disclosure describes various example techniques that may be used to apply merge mode signaling to multi-hypothesis inter prediction. Rather than always signaling one or more of the reference picture index, motion vector predictor index, and/or motion vector difference for multi-hypothesis inter prediction, techniques of this disclosure determine whether motion information for additional hypotheses is coded using merge mode. Alternatively, it may include coding a merge flag indicating whether it is coded using AMVP mode. In particular, signaling motion information for each motion vector may result in signaling excess data, which may excessively increase signaling overhead for the video bitstream, and require excessive encoding, decoding, and other processing operations. It may be possible. By using merge mode to code motion information for multi-hypothesis inter prediction, signaling overhead and encoding, decoding, and other processing operations may be reduced without degrading video quality.

In some examples, a video coder (encoder or decoder) creates a merge candidate list for additional hypotheses such that when motion information for additional hypotheses is coded using merge mode, all merge candidates in the merge candidate list are one-way predictive motion information candidates. You can also configure . For example, if a neighboring block to be used as a merge candidate is coded using bi-prediction including first motion information and second motion information, the video coder determines which of the first motion information or the second motion information You can also construct merge candidates from neighboring blocks using only one. In some examples, a video coder may construct two merge candidates from a neighboring block that is coded using bidirectional prediction: a first merge candidate using the first motion information and a second merge candidate using the second motion information. .

In some examples, the video coder may apply local illumination compensation (LIC) to an additional hypothesis once LIC has been applied to the base hypothesis. A video coder may perform LIC in this manner in addition to, or as an alternative to, the techniques discussed above.

In some examples, a video coder may determine an interpolation filter to apply when calculating values for half sample (half-pixel or half-pel) positions for luminance data. For example, if motion information for additional hypotheses is coded using merge mode, the interpolation filter may be determined according to the interpolation filter of the merge candidate instead of the default mode. As another example, when motion information for additional hypotheses is coded using AMVP, the interpolation filter may be determined according to the default mode. A video coder may perform interpolation filter inheritance in any of these ways, in addition to, or as an alternative to, the techniques discussed above.

1 is a block diagram illustrating an example video encoding and decoding system 100 that may perform the techniques of this disclosure. Techniques of this disclosure generally relate to coding (encoding and/or decoding) video data. Generally, video data includes arbitrary data for processing video. Accordingly, video data may include raw, unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

As shown in FIG. 1 , system 100 includes a source device 102 that provides encoded video data to be decoded and displayed by a destination device 116 in this example. In particular, source device 102 provides video data to destination device 116 via computer-readable medium 110. Source device 102 and destination device 116 include desktop computers, notebook (i.e., laptop) computers, mobile devices, tablet computers, set-top boxes, telephone handsets such as smartphones, televisions, It may include any of a wide range of devices including cameras, display devices, digital media players, video gaming consoles, video streaming devices, broadcast receiver devices, etc. In some cases, source device 102 and destination device 116 may be equipped for wireless communication and thus may be referred to as wireless communication devices.

In the example of FIG. 1 , source device 102 includes video source 104 , memory 106 , video encoder 200 , and output interface 108 . Destination device 116 includes input interface 122, video decoder 300, memory 120, and display device 118. According to this disclosure, video encoder 200 of source device 102 and video decoder 300 of destination device 116 may be configured to apply techniques for coding motion information for multi-hypothesis inter prediction. Accordingly, source device 102 represents an example of a video encoding device, while destination device 116 represents an example of a video decoding device. In other examples, the source device and destination device may include other components or arrangements. For example, source device 102 may receive video data from an external video source, such as an external camera. Likewise, destination device 116 may interface with an external display device, rather than including an integrated display device.

System 100 as shown in Figure 1 is merely an example. In general, any digital video encoding and/or decoding device may perform techniques for coding motion information for multi-hypothesis inter prediction. Source device 102 and destination device 116 are merely examples of such coding devices, where source device 102 generates coded video data for transmission to destination device 116. This disclosure refers to a “coding” device as a device that performs coding (encoding and/or decoding) of data. Accordingly, video encoder 200 and video decoder 300 represent coding devices, particularly video encoder and video decoder examples, respectively. In some examples, source device 102 and destination device 116 may operate in a substantially symmetrical manner such that source device 102 and destination device 116 each include video encoding and decoding components. Therefore, system 100 may support one-way or two-way video transmission between source device 102 and destination device 116, for example, for video streaming, video playback, video broadcasting, or video telephony. there is.

In general, video source 104 represents a source of video data (i.e., raw, unencoded video data) and transmits a sequential series of pictures of the video data to video encoder 200, which encodes the data for the pictures. Frames (also referred to as “frames”) are provided. Video source 104 of source device 102 may include a video capture device, such as a video camera, a video archive containing previously captured raw video, and/or a video feed interface for receiving video from a video content provider. It may be possible. As a further alternative, video source 104 may generate a combination of live video, archived video, and computer-generated video, or computer graphics-based data as the source video. In each case, video encoder 200 encodes captured, pre-captured, or computer-generated video data. Video encoder 200 may reorder the pictures from the received order (sometimes referred to as “display order”) into the coding order for coding. Video encoder 200 may generate a bitstream containing encoded video data. Source device 102 then provides output interface 108 to computer-readable medium 110 for reception and/or retrieval, e.g., by input interface 122 of destination device 116. You can also output encoded video data through.

Memory 106 of source device 102 and memory 120 of destination device 116 represent general-purpose memories. In some examples, memories 106, 120 may store raw video data, such as raw video from video source 104 and raw, decoded video data from video decoder 300. Additionally or alternatively, memories 106, 120 may store software instructions executable, for example, by video encoder 200 and video decoder 300, respectively. Although memory 106 and memory 120 are shown separately from video encoder 200 and video decoder 300 in this example, video encoder 200 and video decoder 300 are functionally similar or serve equivalent purposes. It should be understood that it may also include internal memories. Moreover, memories 106, 120 may store encoded video data, for example, output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106, 120 may be allocated as one or more video buffers, such as to store raw, decoded, and/or encoded video data.

Computer-readable medium 110 may represent any type of medium or device capable of transmitting encoded video data from source device 102 to destination device 116. In one example, computer-readable medium 110 may cause source device 102 to transmit encoded video data directly to destination device 116 in real time, for example, via a radio frequency network or a computer-based network. It represents a communication medium to enable communication. Depending on the communication standard, such as a wireless communication protocol, output interface 108 may modulate a transmitted signal containing encoded video data and input interface 122 may demodulate a received transmitted signal. Communication media may include any wireless or wired communication medium, such as the radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may form part of a packet-based network, such as a local area network, a wide area network, or a global network such as the Internet. Communication media may include routers, switches, base stations, or any other equipment that may be useful to facilitate communication from source device 102 to destination device 116.

In some examples, source device 102 may output encoded data from output interface 108 to storage device 112. Similarly, destination device 116 may access encoded data from storage device 112 via input interface 122. Storage device 112 may be a hard drive, Blu-ray disks, DVDs, CD-ROMs, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data. It may include any of a variety of distributed or locally accessed data storage media, such as:

In some examples, source device 102 may output encoded video data to file server 114 or another intermediate storage device that may store encoded video data generated by source device 102. Destination device 116 may access stored video data from file server 114 via streaming or downloading.

File server 114 may be any type of server device that may store encoded video data and transmit the encoded video data to destination device 116. File server 114 may be a web server (e.g., for a website), a server configured to provide file transfer protocol services (such as the File Transfer Protocol (FTP) or the File Delivery over Unidirectional Transport (FLUTE) protocol), and content delivery. It may represent a network (CDN) device, a hypertext transfer protocol (HTTP) server, a multimedia broadcast multicast service (MBMS) or enhanced MBMS (eMBMS) server, and/or a network attached storage (NAS) device. File server 114 may additionally or alternatively implement one or more HTTP streaming protocols, such as Dynamic Adaptive Streaming over HTTP (DASH), HTTP Live Streaming (HLS), Real-Time Streaming Protocol (RTSP), HTTP Dynamic Streaming, etc.

Destination device 116 may access encoded video data from file server 114 via any standard data connection, including an Internet connection. This may be a wireless channel (e.g., Wi-Fi connection), a wired connection (e.g., Digital Subscriber Line (DSL), cable modem, etc.), or any of these, suitable for accessing encoded video data stored on file server 114. It may also include a combination of both. Input interface 122 may be configured to operate in accordance with any one or more of the various protocols discussed above for retrieving or receiving media data from file server 114, or other such protocols for retrieving media data. there is.

Output interface 108 and input interface 122 may include wireless transmitters/receivers, modems, wired networking components (e.g., Ethernet cards), wireless communication components operating in accordance with any of the various IEEE 802.11 standards. , or may represent other physical components. In examples where output interface 108 and input interface 122 include wireless components, output interface 108 and input interface 122 can support cellular wireless components such as 4G, 4G-Long Term Evolution (LTE), LTE Advanced, 5G, etc. Depending on the communication standard, it may be configured to transmit data such as encoded video data. In some examples where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 may be configured to support other wireless signals, such as the IEEE 802.11 standard, IEEE 802.15 standard (e.g., ZigBee™), Bluetooth™ standard, etc. Depending on standards, it may be configured to transmit data such as encoded video data. In some examples, source device 102 and/or destination device 116 may include respective system-on-a-chip (SoC) devices. For example, source device 102 may include a SoC device to perform functionality due to video encoder 200 and/or output interface 108, and destination device 116 may include video decoder 300. and/or a SoC device to perform functionality due to input interface 122.

Over-the-air television broadcasts, cable television transmissions, satellite television transmissions, Internet streaming video transmissions such as dynamic adaptive streaming over HTTP (DASH), digital video encoded onto a data storage medium. The techniques of this disclosure may be applied to video coding to support any of a variety of multimedia applications, such as decoding of digital video stored on a data storage medium, or other applications.

Input interface 122 of destination device 116 receives the encoded video bitstream from computer-readable medium 110 (e.g., communication medium, storage device 112, file server 114, etc.). An encoded video bitstream consists of syntax elements with values that describe the processing and/or characteristics of video blocks or other coded units (e.g., slices, pictures, groups of pictures, sequences, etc.) , may also include signaling information defined by video encoder 200, which is also used by video decoder 300. Display device 118 displays decoded pictures of the decoded video data to the user. Display device 118 may represent any of a variety of display devices, such as a liquid crystal display (LCD), plasma display, organic light emitting diode (OLED) display, or other type of display device.

Although not shown in Figure 1, in some examples, video encoder 200 and video decoder 300 may be integrated with an audio encoder and/or an audio decoder, respectively, appropriate MUX-DEMUX units, or other hardware and/or Or it may include software to handle multiplexed streams containing both audio and video in a common data stream.

Video encoder 200 and video decoder 300 each include a variety of suitable encoder and/or decoder circuitry, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), and field programming. It may be implemented as any of possible gate arrays (FPGAs), discrete logic, software, hardware, firmware, or any combinations thereof. If the techniques are implemented in part in software, the device may store instructions for the software in a suitable, non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to perform the techniques of the present disclosure. . Each of the video encoder 200 and video decoder 300 may be included in one or more encoders or decoders, any of which may be integrated as part of a combined encoder/decoder (CODEC) in each device. A device containing video encoder 200 and/or video decoder 300 may include an integrated circuit, a microprocessor, and/or a wireless communication device, such as a cellular telephone.

Video encoder 200 and video decoder 300 support video coding standards, such as ITU-T H.265, also referred to as High Efficiency Video Coding (HEVC), or extensions thereof, such as multi-view and/or scalable. It may also operate according to video coding extensions. Alternatively, video encoder 200 and video decoder 300 may operate according to other proprietary or industry standards, such as ITU-T H.266, also referred to as Versatile Video Coding (VVC). In other examples, video encoder 200 and video decoder 300 may support a proprietary video codec/format, such as AOMedia Video 1 (AV1), extensions of AVI, and/or successors to AV1 (e.g., AV2). It may operate depending on . In other examples, video encoder 200 and video decoder 300 may operate according to other proprietary formats or industry standards. However, the techniques of this disclosure are not limited to any particular coding standard or format. In general, video encoder 200 and video decoder 300 may be configured to perform the techniques of this disclosure along with any video coding techniques that code motion information for multi-hypothesis inter prediction.

In general, video encoder 200 and video decoder 300 may perform block-based coding of pictures. The term “block” generally refers to a structure containing data to be processed (eg, to be encoded, decoded, or otherwise used in an encoding and/or decoding process). For example, a block may include a two-dimensional matrix of samples of luminance and/or chrominance data. In general, video encoder 200 and video decoder 300 may code video data expressed in YUV (eg, Y, Cb, Cr) format. That is, rather than coding red, green, and blue (RGB) data for samples of a picture, video encoder 200 and video decoder 300 may code luminance and chrominance components, where the chrominance components are red It may include both hue and blue hue chrominance components. In some examples, video encoder 200 converts received RGB formatted data to a YUV representation before encoding, and video decoder 300 converts the YUV representation to RGB format. Alternatively, pre- and post-processing units (not shown) may perform these conversions.

This disclosure may generally refer to coding (e.g., encoding and decoding) of pictures to include the process of encoding or decoding data of a picture. Similarly, this disclosure may refer to the process of encoding or decoding data for blocks, such as coding blocks of a picture to include prediction and/or residual coding. An encoded video bitstream typically includes a set of values for syntax elements that indicate partitioning of pictures into blocks and coding decisions (e.g., coding modes). Accordingly, references to coding a picture or block should generally be understood as coding values for syntax elements that form the picture or block.

HEVC defines various blocks including coding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video coder (such as video encoder 200) partitions a coding tree unit (CTU) into CUs according to a quadtree structure. That is, the video coder partitions the CTUs and CUs into four equal, non-overlapping squares, and each node of the quadtree has 0 or 4 child nodes. Nodes without child nodes may be referred to as “leaf nodes,” and the CUs of these leaf nodes may include one or more PUs and/or one or more TUs. The video coder may further partition PUs and TUs. For example, in HEVC, the residual quadtree (RQT) represents the partitioning of TUs. In HEVC, PUs represent inter prediction data, while TUs represent residual data. CUs that are intra predicted include intra prediction information such as intra mode indication.

As another example, video encoder 200 and video decoder 300 may be configured to operate according to VVC. According to VVC, a video coder (e.g., video encoder 200) partitions a picture into a plurality of coding tree units (CTUs). The video encoder 200 may partition CTUs according to a tree structure, such as a quadtree-binary tree (QTBT) structure or a multitype tree (MTT) structure. The QTBT structure eliminates the concept of multiple partition types, such as the distinction between CUs, PUs, and TUs in HEVC. The QTBT structure includes two levels: a first level partitioned according to quadtree partitioning, and a second level partitioned according to binary tree partitioning. The root node of the QTBT structure corresponds to the CTU. Leaf nodes of binary trees correspond to coding units (CUs).

In the MTT partitioning structure, blocks may be partitioned using quadtree (QT) partitions, binary tree (BT) partitions, and one or more types of triple tree (TT) (also called ternary tree (TT)) partitions. A triple or ternary tree partition is a partition in which a block is split into three subblocks. In some examples, a triple or ternary tree partition splits a block into three subblocks without splitting the original block through the center. Partitioning types in MTT (e.g., QT, BT, and TT) may be symmetric or asymmetric.

When operating according to the AV1 codec, video encoder 200 and video decoder 300 may be configured to code video data in blocks. In AV1, the largest coding block that can be processed is referred to as a superblock. In AV1, a superblock can be either 128x128 luma samples or 64x64 luma samples. However, in subsequent video coding formats (eg, AV2), a superblock may be defined by different (eg, larger) luma sample sizes. In some examples, a superblock is the top level of a block quadtree. Video encoder 200 may further partition the superblock into smaller coding blocks. Video encoder 200 may partition superblocks and other coding blocks into smaller blocks using square or non-square partitioning. Non-square blocks may include N/2xN, NxN/2, N/4xN, and NxN/4 blocks. Video encoder 200 and video decoder 300 may perform separate prediction and transformation processes for each of the coding blocks.

AV1 also defines tiles of video data. A tile is a rectangular array of superblocks that may be coded independently from other tiles. That is, the video encoder 200 and the video decoder 300 may respectively encode and decode coding blocks within a tile without using video data from other tiles. However, video encoder 200 and video decoder 300 may also perform filtering across tile boundaries. Tiles may or may not be uniform in size. Tile-based coding may enable parallel processing and/or multi-threading for encoder and decoder implementations.

In some examples, video encoder 200 and video decoder 300 may use a single QTBT or MTT structure to represent the luminance and chrominance components, respectively, while in other examples video encoder 200 and video decoder 300 is two or more QTBT or MTT structures, such as one QTBT/MTT structure for the luminance component and another QTBT/MTT structure for both chrominance components (or two QTBT/MTT structures for each chrominance component) You can also use structures.

Video encoder 200 and video decoder 300 may be configured to use quadtree partitioning, QTBT partitioning, MTT partitioning, superblock partitioning, or other partitioning structures.

In some examples, a CTU is a coding tree block (CTB) of luma samples, two corresponding CTBs of chroma samples of a picture with three sample arrays, or three separate color planes and syntax used to code the samples. Contains the CTB of samples of a picture or monochrome picture coded using the structures. A CTB may be an NxN block of samples for some value of N such that the division of a component into CTBs is a partitioning. A component can be an array or a single sample from one of three arrays (luma and two chroma) for a picture in 4:2:0, 4:2:2, or 4:4:4 color format, or a single sample in monochrome format. It may be an array for a picture or a single sample of an array. In some examples, the coding block is an MxN block of samples for some values of M and N such that the division of the CTB into coding blocks is a partitioning.

Blocks (eg, CTUs or CUs) may be grouped in various ways in a picture. As an example, a brick may refer to a rectangular area of CTU rows within a specific tile in a picture. A tile may be a rectangular area of CTUs within a specific tile row and a specific tile row in a picture. A tile row refers to a rectangular region of CTUs with a height equal to the height of the picture and a width specified by syntax elements (e.g., as in a picture parameter set). A tile row refers to a rectangular region of CTUs with a height specified by syntax elements (e.g., as in a picture parameter set) and a width equal to the width of the picture.

In some examples, a tile may be partitioned into multiple bricks, each of which may contain one or more CTU rows within the tile. A tile that is not partitioned into multiple bricks may also be referred to as a brick. However, bricks that are a true subset of tiles may not be referred to as tiles. Bricks in a picture may also be arranged into slices. A slice may be an integer number of bricks of a picture that may be contained exclusively in a single network abstraction layer (NAL) unit. In some examples, a slice includes multiple complete tiles or only a contiguous sequence of complete bricks of one tile.

This disclosure uses "NxN" and "N by N" interchangeably to refer to the sample dimensions of a block (such as a CU or other video block) with respect to the vertical and horizontal dimensions, e.g., 16x16 samples. Alternatively, 16 by 16 samples may be used. Typically, a 16x16 CU will have 16 samples in the vertical direction (y = 16) and 16 samples in the horizontal direction (x = 16). Likewise, an NxN CU typically has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non-negative integer value. Samples in a CU may be arranged into rows and columns. Additionally, CUs do not necessarily need to have the same number of samples in the horizontal direction as in the vertical direction. For example, CUs may contain NxM samples, where M is not necessarily equal to N.

Video encoder 200 encodes video data for CUs representing prediction and/or residual information, and other information. Prediction information indicates how a CU should be predicted to form a prediction block for the CU. Residual information generally represents sample-by-sample differences between samples of the CU before encoding and the prediction block.

To predict a CU, the video encoder 200 may generally form a prediction block for the CU through inter-prediction or intra-prediction. Inter prediction generally refers to predicting a CU from data in a previously coded picture, while intra prediction generally refers to predicting a CU from previously coded data in the same picture. To perform inter prediction, the video encoder 200 may generate a prediction block using one or more motion vectors. Video encoder 200 may generally perform motion search to identify a reference block that closely matches a CU, for example, with respect to differences between the CU and the reference block. The video encoder 200 calculates the sum of absolute difference (SAD), sum of squared differences (SSD), mean absolute difference (MAD), and mean squared differences (MSD) to determine whether the reference block closely matches the current CU. , or other such difference calculations may be used to calculate the difference metric. In some examples, video encoder 200 may predict the current CU using unidirectional prediction or bidirectional prediction.

In HEVC, as an example, a bidirectional prediction (also referred to as bidirectional prediction) signal is generated by averaging two prediction signals obtained from two different reference pictures and/or using two different motion vectors. In VVC, as another example, the bidirectional prediction mode is extended beyond simple averaging to allow weighted averaging of two prediction signals. The following equation represents an example of prediction block generation using bidirectional prediction:

(One)

In Equation 1 above, P _bi-pred represents the prediction block formed using bidirectional prediction, P ₀ represents the first prediction block formed from the first set of motion information and the first reference picture, and P ₁ represents the second represents the second prediction block formed from the set of motion information and the second reference picture, w represents the weight value, and ">>" represents the bitwise right shift operator. In VVC, five weight values for w are allowed in weighted averaging two-way prediction, w ∈ {-2,3,4,5,10}. For each bidirectional predicted CU, the weight w is determined in one of two ways: 1) For non-merged CUs, the weight index is signaled after the motion vector difference; 2) For merge CU, the weight index is inferred from neighboring blocks based on the merge candidate index. In VVC, bi-prediction with CU level weights (BCW) applies only to CUs with luma samples greater than or equal to 256 (i.e., CU width times CU height is greater than or equal to 256). For low-latency pictures, all five weights are used. For non-low-latency pictures, only three weights (w∈{3,4,5}) are used.

In HEVC, video coders use quarter luma samples (quarter- luma samples) if use_integer_mv_flag (i.e., a syntax element indicating whether integer level or sub-integer level precision is used) is equal to 0 (indicating sub-integer precision) in the slice header. In units of luma-sample, motion vector differences (MVDs) may be coded, representing the differences between the CU's predicted motion vector and the motion vector. VVC introduced the CU-level adaptive motion vector resolution (AMVR) method. AMVR allows the MVD of a CU to be coded with different precisions. Depending on the mode for the current CU in the VVC (e.g., normal AMVP mode or affine AVMP mode), the MVDs of the current CU may be adaptively selected as follows:

ㆍNormal AMVP mode: quarter luma sample, half-luma-sample, integer luma sample or 4 luma sample.

ㆍAffine AMVP mode: quarter luma sample, integer luma sample or 1/16 luma sample.

A video coder may conditionally code CU level MVD resolution if the current CU has at least one non-zero MVD component, per VVC. If all MVD components (i.e., both horizontal and vertical MVDs for reference list L0 and reference list L1) are 0, then the video coder can encode the quarter luma sample MVD without coding additional data to express the precision (resolution). It can also be inferred that resolution is used.

Per VVC, for a CU with at least one non-zero MVD component, a first flag is signaled to indicate whether quarter luma sample MVD precision is used for the CU. If the first flag is 0, no further signaling is needed and quarter luma sample MVD precision is used for the current CU. Otherwise, the video coder codes a second flag indicating that half luma sample or other MVD precisions (integer or 4 luma samples) are used for the normal AMVP CU. In the case of half luma samples, per VVC, a 6-tap interpolation filter is used for the half luma sample position instead of the default 8-tap interpolation filter. Otherwise, per VVC, a third flag is signaled to indicate whether integer luma sample MVD precision or 4 luma sample MVD precision is used for normal AMVP CUs. In the case of an affine AMVP CU, a second flag is used to indicate whether integer luma sample MVD precision or 1/16 luma sample MVD precision is used. To ensure that the restored MV has the intended precision (quarter luma samples, half luma samples, integer luma samples, or 4 luma samples), the video coder sets the motion vector predictors for the CU to the same precision as the MVD: Before adding the predictors with MVD, you can also round them. The video coder may round the motion vector predictors toward 0 (i.e., a negative motion vector predictor is rounded toward positive infinity and a positive motion vector predictor is rounded toward negative infinity).

2 is a conceptual diagram illustrating a table representing an example scheme for one-way predictive motion vector selection for geometric partitioning mode (GPM). VVC includes GPM for inter prediction. In VVC, geometric partitioning mode is one of the merge modes, along with other merge modes including regular merge mode, merge mode with MVD (MMVD), cross-component intra prediction (CIIP) mode, and subblock merge mode. As a type, it is signaled using the CU level flag. A total of 64 partitions are supported by the geometric partitioning mode for each possible CU size w × h = 2 ^m × 2 ⁿ (m, n ∈ {3…6}) excluding 8x64 and 64x8.

Per VVC, when this mode is used, the CU is split into two parts by a geometrically located straight line. Each part of the geometric partition in CU is inter-predicted using its unique motion; Only one-way prediction is allowed for each partition, i.e. each part has 1 motion vector and 1 reference index. One-way prediction motion constraints are applied to ensure that only two motion-compensated predictions are needed for each CU, identical to conventional two-way prediction. The one-way predicted motion for each partition is derived using a process described as follows:

The one-way prediction candidate list is directly derived from the merge candidate list constructed according to the extended merge prediction process in VVC. We denote n as the index of a single prediction motion in the geometric unidirectional prediction candidate list. The LX motion vector of the nth extended merge candidate (X is equal to the parity of n) is used as the nth unidirectional prediction motion vector for the geometric partitioning mode. These motion vectors are marked with “x” in Figure 2. In case the corresponding LX motion vectors of the n extended merge candidates do not exist, the L(1 -

Per VVC, if geometric partitioning mode is used for the current CU, the video coder adds a geometric partition index indicating the partition mode of the geometric partition (angle and offset), and two merge indices (one for each partition) It can also be coded as . According to VVC, the number of maximum GPM candidate sizes is explicitly coded in the Sequence Parameter Set (SPS) and specifies the syntax binarization for GPM merge indices. After predicting each part of the geometric partition, the video coder may adjust sample values along the geometric partition edge using blending processing with adaptive weights.

In almost all previous and current video coding standards, video coders may employ either one-way or two-way methods to temporally predict blocks of video data, which is the single prediction hypothesis. Multi-hypothesis prediction (MHP) is a method used by Winken et al., “Multi-hypothesis inter-prediction”, 10th JVET Conference on ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11, April 10, 2018. -20 days, document number JVET-J0041; Winken et al., “CE10: Multi-Hypothesis Inter Prediction (Tests 1.5 - 1.8)”, 11th JVET Conference on ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11, July 10, 2018. -18 days, document JVET-K0269; Winken et al., "CE10: Multi-Hypothesis Inter Prediction (Tests 1.2.a - 1.2.c)" 12th JVET Conference on ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11, 2018. 3-12 October, document JVET-L0148 (v3); and Winken et al., “CE10: Multi-hypothesis inter prediction (Test 10.1.2)” 13th JVET conference on ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11, 9 January 2019. -18, described in document number JVET-M0425. In MHP per VVC, the inter prediction method allows weighted superposition of more than two motion compensated prediction signals. The resulting overall prediction signal is obtained by sample-wise weighted superposition. With the one-way/two-way prediction signal p _{uni / bi} and the first additional inter prediction signal/hypothesis h ₃ , the resulting prediction signal p ₃ is obtained, per VVC, as follows:

(2)

In equation (2), p ₃ represents the resulting prediction signal, p _uni/bi represents the first prediction block from the first prediction hypothesis, h3 represents the second prediction block from the second prediction hypothesis, and α represents the weight value. In VVC, the weighting factor α is specified by the syntax element add_hyp_weight_idx according to the following mapping:

Similar to above, more than one additional prediction signal may be used. For each VVC, the resulting overall prediction signal is iteratively accumulated with each additional prediction signal as follows:

(3)

The resulting overall prediction signal is obtained as the last p _n (i.e. p _n with the largest index n ).

For inter prediction blocks using MERGE mode (rather than SKIP mode), additional inter prediction signals may also be specified. For additional prediction signals, per VVC, one of the two AMVP candidate lists is used:

ㆍIf the picture order count (POC) of the reference picture of the additional prediction signal is the same as the POC of the used list1 reference picture, the list1 AMVP candidate list is used.

ㆍOtherwise, the list0 candidate list is used.

Chang et al., "Compression efficiency methods beyond VVC" 21st JVET Conference of ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29, 6-15 January 2021, Paper No. JVET-U0100 for local lighting Explain compensation (LIC). LIC is an inter-prediction technique that models the local illumination change between the current block and its prediction block as a function of that between the current block template and the reference block template. The parameters of the function can be denoted by scale α and offset β , which forms a linear equation to compensate for illumination changes, i.e. α *p[x]+ β , where p[x] is the position x on the reference picture. is the reference sample pointed by the MV. Since α and β can be derived based on the current block template and the reference block template, no signaling overhead is required for them, except that the LIC flag is signaled for AMVP mode to indicate the use of LIC. .

Local illumination compensation for unidirectional prediction inter-CUs can also be found in Seregin et al., “CE4-3.1a and CE4-3.1b: Unidirectional local illumination compensation with affine prediction,” July 3-12, 2019, document number JVET-O0066. , described with the following variations:

ㆍIntra neighborhood samples can be used in LIC parameter derivation;

· LIC is disabled for blocks with less than 32 luma samples;

• For both non-subblock and affine modes, LIC parameter derivation is performed based on template block samples corresponding to the current CU, instead of partial template block samples corresponding to the first upper left 16x16 unit;

ㆍSamples of the reference block are generated using blocks MV and MC without rounding with integer-pel precision.

Referring back to FIG. 1, according to various techniques of this disclosure, video encoder 200 and video decoder 300 may be configured to perform merge mode for multi-hypothesis inter prediction. For example, for the merge mode for additional hypotheses, rather than always coding the reference picture index, motion vector predictor index, and motion vector difference (as in AMVP mode) for the additional hypothesis, the video encoder 200 and Video decoder 300 may code a merge flag to indicate whether the motion information for the additional hypothesis is coded using merge mode or AMVP mode. If the merge flag is true, video encoder 200 and video decoder 300 may code the merge index to indicate merge candidates for additional hypotheses. If the merge flag is false, video encoder 200 and video decoder 300 may code the reference picture index, motion vector predictor index, and motion vector difference for additional hypotheses.

In some examples, for one or more additional hypotheses, video encoder 200 and video decoder 300 may configure merge candidates for the merge mode for the additional hypotheses such that each merge candidate represents a unidirectional predictive motion. there is. In some examples, video encoder 200 and video decoder 300 may use a one-way prediction candidate list, such as in a geometric partitioning mode, such as in VVC. Accordingly, the merge mode for additional hypotheses may share the same merge candidate list as the geometric partitioning mode.

In other words, to construct a merge candidate list, if a neighboring block is predicted using bidirectional prediction, the video encoder 200 and video decoder 300 may construct one or two merge candidates from the neighboring block. . If the neighboring block is predicted using bi-directional prediction, the neighboring block will contain both first motion information for the first motion vector and second motion information for the second motion vector. The video encoder 200 and the video decoder 300 may configure a merge candidate from either or both first motion information and/or second motion information. Accordingly, video encoder 200 and video decoder 300 may form a unidirectional prediction merge candidate from neighboring blocks, including using either first motion information or second motion information. Additionally, the video encoder 200 and the video decoder 300 may use the second motion information to form a second unidirectional prediction merge candidate from the neighboring block.

In some examples, video encoder 200 and video decoder 300 may code the merge flag for the additional hypothesis as the merge flag for the basic mode (where “basic mode” refers to the mode to which the additional hypothesis is applied on top). , for example, refers to one-way prediction or two-way prediction). In some examples, video encoder 200 and video decoder 300 may use the same CABAC context to code this merge flag. In other examples, video encoder 200 and video decoder may code the merge flag for an additional hypothesis using a new CABAC context that is different from the CABAC context that was used for the merge flag signaled in the default mode.

In some examples, video encoder 200 and video decoder 300 may code the merge index for the additional hypothesis using the same CABAC context(s) used to signal the merge index for the MERGE mode. In other examples, video encoder 200 and video decoder 300 code merge indices for additional hypotheses using CABAC context(s) different from the CABAC context(s) used to code merge indices in MERGE mode. You may.

By allowing merge mode to be used to code motion information for additional hypotheses according to the techniques of this disclosure, coded motion information in the bitstream may be reduced. That is, rather than coding each of the candidate index, motion vector difference, reference picture list indicator, and reference index as motion information for additional hypotheses, the video encoder 200 and video decoder 300 provide motion information for additional hypotheses. We may code a merge index that indicates whether a merge mode is used for coding, and if so, we may simply code a candidate index per merge mode. In this way, a more accurate prediction block can be formed for the current block, and the bitrate associated with the coding data used to form the prediction block can be reduced.

In some examples, when merge modes are used for multiple additional hypotheses, video encoder 200 and video decoder 300 select the merge candidate that was used in the previous additional hypothesis from the merge candidate list for the current additional hypothesis. (s) can also be removed. Therefore, the number of merge candidates in the current additional hypothesis may be reduced. Therefore, the signaling of the merge index can be modified correspondingly to save bits. For example, if merge candidate i is used in the first additional hypothesis and the total number of candidates is N, video encoder 200 and video decoder 300 may remove merge candidate i from the merge candidate list for the second additional hypothesis. there is. Then the total number of merge candidates for the second additional hypothesis will be N-1. Accordingly, the merge index in the second additional hypothesis may be coded with a truncated binarized code, for example, a truncated unary code with a maximum codeword length of N-1 instead of N.

In some examples, video encoder 200 and video decoder 300 may apply local lighting compensation (LIC) to additional hypotheses in merge and/or AMVP modes when LIC is applied in base mode. there is. In other examples, video encoder 200 and video decoder 300 may infer that if the additional hypothesis uses AMVP mode and LIC was applied to the basic mode, then LIC will be applied to the additional hypotheses. If the additional hypothesis uses merge mode and LIC was applied to the base mode, video encoder 200 and video decoder 300 may code the LIC flag of the merge candidate indicating whether LIC should be applied to the additional hypothesis.

In VVC, in the case of half luma sample MVD resolution, a 6-tap interpolation filter is used instead of the default 8-tap interpolation filter for the half luma sample position. Merge candidates may also inherit these filter switching. According to the techniques of this disclosure, if motion information for an additional hypothesis is coded using a merge mode, whether to apply an alternative switching filter to interpolate the half luma sample position or other sample positions instead of the default mode's merge candidate , one may rely on merging candidates for additional hypotheses. Alternatively, if the additional hypothesis is AMVP mode, whether to apply an alternative switching filter to interpolate the half luma sample position or other positions may depend on whether the interpolation filter switching is performed in default mode.

Some examples of VVC also provide an affine motion compensation mode, which may be considered an inter prediction mode. In an affine motion compensation mode, video encoder 200 may determine two or more motion vectors representing non-translational motion, such as zooming in or out, rotation, perspective motion, or other irregular motion types.

To perform intra prediction, video encoder 200 may select an intra prediction mode to generate a prediction block. Some examples of VVC provide 67 intra prediction modes, including planar mode and DC mode, as well as various directional modes. In general, video encoder 200 selects an intra prediction mode that describes neighboring samples for the current block (e.g., a block of a CU) for which samples of the current block will be predicted. Such samples are generally the current block in the same picture as the current block, assuming that video encoder 200 codes the CTUs and CUs in raster scan order (left to right, top to bottom). It may be above, above and to the left of, or to the left of the block.

The video encoder 200 encodes data indicating the prediction mode for the current block. For example, for an inter prediction mode, video encoder 200 may encode motion information for the corresponding mode, as well as data indicating which of the various available inter prediction modes is used. For unidirectional or bidirectional inter prediction, for example, video encoder 200 may encode motion vectors using advanced motion vector prediction (AMVP) or merge mode. Video encoder 200 may encode motion vectors for an affine motion compensation mode using similar modes.

AV1 includes two general techniques for encoding and decoding coding blocks of video data. Two common techniques are intra prediction (eg, intra frame prediction or spatial prediction) and inter prediction (eg, inter frame prediction or temporal prediction). In the context of AV1, when predicting blocks of the current frame of video data using intra prediction mode, video encoder 200 and video decoder 300 do not use video data from other frames of video data. For most intra prediction modes, video encoder 200 encodes blocks of the current frame based on the difference between sample values in the current block and predicted values generated from reference samples in the same frame. The video encoder 200 determines predicted values generated from reference samples based on the intra prediction mode.

Following prediction, such as intra-prediction or inter-prediction of a block, video encoder 200 may calculate residual data for the block. Residual data, such as a residual block, represents sample-by-sample differences between a block and a prediction block for that block, formed using a corresponding prediction mode. The video encoder 200 may apply one or more transforms to the residual block to generate transformed data in the transform domain instead of the sample domain. For example, video encoder 200 may apply a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform to the residual video data. Additionally, the video encoder 200 may apply a secondary transform following the primary transform, such as mode-dependent non-separable secondary transform (MDNSST), signal dependent transform, Karhunen-Loeve transform (KLT), etc. Video encoder 200 generates transform coefficients following application of one or more transforms.

As mentioned above, following any transforms to generate transform coefficients, video encoder 200 may perform quantization of the transform coefficients. Quantization generally refers to a process in which transform coefficients are quantized to reduce as much as possible the amount of data used to represent the transform coefficients, thereby providing additional compression. By performing a quantization process, video encoder 200 may reduce the bit depth associated with some or all of the transform coefficients. For example, video encoder 200 may round down n-bit values to m-bit values during quantization, where n is greater than m. In some examples, to perform quantization, video encoder 200 may perform a bitwise right shift of the value to be quantized.

Following quantization, video encoder 200 may scan the transform coefficients to generate a one-dimensional vector from a two-dimensional matrix containing the quantized transform coefficients. The scan may be designed to place higher energy (and therefore lower frequency) transform coefficients in front of the vector and place lower energy (and therefore higher frequency) transform coefficients behind the vector. In some examples, video encoder 200 may scan quantized transform coefficients utilizing a predefined scan order to generate a serialized vector and then entropy encode the quantized transform coefficients of the vector. In other examples, video encoder 200 may perform adaptive scan. After scanning the quantized transform coefficients to form a one-dimensional vector, video encoder 200 may entropy encode the one-dimensional vector, for example, according to context adaptive binary arithmetic coding (CABAC). Video encoder 200 may also entropy encode values for syntax elements that describe metadata associated with the encoded video data for use by video decoder 300 in decoding the video data.

To perform CABAC, the video encoder 200 may assign a context within a context model to a symbol to be transmitted. Context may relate to, for example, whether a symbol's neighboring values are zero or not. The probability determination may be based on the context given to the symbol.

Video encoder 200 encodes video, e.g., in a picture header, block header, slice header, or other syntax data, such as a sequence parameter set (SPS), picture parameter set (PPS), or video parameter set (VPS). Syntax data such as block-based syntax data, picture-based syntax data, and sequence-based syntax data may be additionally generated for the decoder 300. Video decoder 300 may likewise decode such syntax data to determine how to decode the corresponding video data.

In this way, video encoder 200 encodes encoded video data, such as syntax elements that describe the partitioning of a picture into blocks (e.g., CUs) and prediction and/or residual information for the blocks. You can also create a bitstream. Finally, video decoder 300 may receive the bitstream and decode the encoded video data.

In general, video decoder 300 performs a process reciprocal to that performed by video encoder 200 to decode encoded video data in a bitstream. For example, video decoder 300 may decode values for syntax elements of a bitstream using CABAC in a manner that is interactive, but substantially similar, to the CABAC encoding process of video encoder 200. Syntax elements may define partitioning information for partitioning of a picture into CTUs and partitioning of each CTU according to a corresponding partition structure, such as a QTBT structure, thereby defining CUs of the CTU. Syntax elements may further define prediction and residual information for blocks (eg, CUs) of video data.

Residual information may be expressed, for example, by quantized transform coefficients. The video decoder 300 may dequantize and inverse transform the quantized transform coefficients of a block to reproduce a residual block for the block. Video decoder 300 uses the signaled prediction mode (intra or inter prediction) and associated prediction information (e.g., motion information for inter prediction) to form a prediction block for the block. Thereafter, the video decoder 300 may combine the prediction block and the residual block (on a sample-by-sample basis) to reproduce the original block. Video decoder 300 may perform additional processing, such as performing a deblocking process to reduce visual artifacts along the boundaries of a block.

This disclosure may generally refer to “signaling” certain information, such as syntax elements. The term “signaling” may generally refer to the communication of values for syntax elements and/or other data used to decode encoded video data. That is, the video encoder 200 may signal values for syntax elements in the bitstream. In general, signaling refers to generating value in a bitstream. As mentioned above, source device 102 may store syntax elements in storage device 112 for later retrieval by destination device 116, as may occur in non-real-time or substantially real-time bitstream. may be transmitted to the destination device 116.

In this way, video encoder 200 and video decoder 300 represent examples of devices for decoding (and/or encoding) video data, including: a memory configured to store video data; and one or more processors implemented in circuitry, wherein the one or more processors: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element is such that motion information for the second prediction block is coded using merge mode. code the merge mode syntax element to indicate whether to do so; coding motion information for a second prediction block according to a merge mode syntax element, wherein, to code the motion information, the one or more processors are configured to configure the merge mode syntax element to cause the motion information for the second prediction block to use merge mode. coding the motion information, when indicating that it is coded, configured to form a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information; generate a second prediction block for the current block of video data using the motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and is configured to decode the current block using the multi-hypothesis prediction block.

3 is a block diagram illustrating an example video encoder 200 that may perform the techniques of this disclosure. 3 is provided for illustrative purposes and should not be considered limiting of the techniques as broadly illustrated and described in this disclosure. For purposes of explanation, this disclosure describes video encoder 200 according to the techniques of VVC (ITU-T H.266, under development), and HEVC (ITU-T H.265). However, the techniques of this disclosure may be performed by video encoding devices configured with other video coding standards and video coding formats, such as AV1 and successors to the AV1 video coding format.

In the example of Figure 3, the video encoder 200 includes a video data memory 230, a mode selection unit 202, a residual generation unit 204, a transform processing unit 206, a quantization unit 208, and a dequantization unit ( 210), an inverse transform processing unit 212, a restoration unit 214, a filter unit 216, a decoded picture buffer (DPB) 218, and an entropy encoding unit 220. Video data memory 230, mode selection unit 202, residual generation unit 204, transform processing unit 206, quantization unit 208, inverse quantization unit 210, inverse transform processing unit 212, restoration unit. Any or all of 214, filter unit 216, DPB 218, and entropy encoding unit 220 may be implemented in one or more processors or in processing circuitry. For example, units of video encoder 200 may be implemented as one or more circuits or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Moreover, video encoder 200 may include additional or alternative processors or processing circuitry to perform these and other functions.

Video data memory 230 may store video data to be encoded by components of video encoder 200. Video encoder 200 may receive video data stored in video data memory 230, for example, from video source 104 (Figure 1). DPB 218 may serve as a reference picture memory to store reference video data for use in prediction of subsequent video data by video encoder 200. Video data memory 230 and DPB 218 may be memory devices such as DRAM, including synchronous dynamic random access memory (DRAM) (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. It may be formed by any of a variety of memory devices. Video data memory 230 and DPB 218 may be provided by the same memory device or separate memory devices. In various examples, video data memory 230 may be on-chip with other components of video encoder 200, as illustrated, or off-chip relative to those components. .

In this disclosure, references to video data memory 230 are limited to memory internal to video encoder 200, unless specifically stated otherwise, or to memory external to video encoder 200, unless specifically stated otherwise. It should not be interpreted as being Rather, references to video data memory 230 should be understood as a reference memory that stores video data that video encoder 200 receives for encoding (e.g., video data for the current block to be encoded). Memory 106 of FIG. 1 may also provide temporary storage of outputs from various units of video encoder 200.

Various units in FIG. 3 are illustrated to aid understanding of operations performed by video encoder 200. Units may be implemented as fixed function circuits, programmable circuits, or a combination thereof. Fixed function circuits refer to circuits that provide specific functionality and are preset for the operations that can be performed. Programmable circuits refer to circuits that may be programmed to perform various tasks, providing flexible functionality in the operations that may be performed. For example, programmable circuits may execute software or firmware that causes the programmable circuits to operate in a manner defined by instructions of the software or firmware. Fixed function circuits may execute software instructions (eg, to receive parameters or output parameters), but the types of operations they perform are generally invariant. In some examples, one or more of the units may be separate circuit blocks (fixed function or programmable), and in some examples, one or more of the units may be integrated circuits.

Video encoder 200 may include arithmetic logic units (ALUs), elementary function units (EFUs), digital circuits, analog circuits, and/or programmable cores formed from programmable circuits. . In examples where the operations of video encoder 200 are performed using software executed by programmable circuits, memory 106 (FIG. 1) stores instructions in the software that video encoder 200 receives and executes (e.g. , object code), or another memory (not shown) within the video encoder 200 may store such instructions.

Video data memory 230 is configured to store received video data. Video encoder 200 may retrieve a picture of video data from video data memory 230 and provide the video data to residual generation unit 204 and mode selection unit 202. The video data in video data memory 230 may be raw video data to be encoded.

The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra prediction unit 226. Mode selection unit 202 may include additional functional units for performing video prediction according to different prediction modes. As examples, mode selection unit 202 may include a palette unit, an intra block copy unit (which may be part of motion estimation unit 222 and/or motion compensation unit 224), an affine unit, a linear model (LM) unit, etc. It may also be included.

Mode selection unit 202 typically coordinates multiple encoding passes to test combinations of encoding parameters and resulting rate-distortion values for those combinations. Encoding parameters may include partitioning of CTUs into CUs, prediction modes for CUs, transformation types for residual data of CUs, quantization parameters for residual data of CUs, etc. Mode selection unit 202 may finally select a combination of encoding parameters that has better rate-distortion values than other tested combinations.

Video encoder 200 may partition a picture retrieved from video data memory 230 into a series of CTUs and encapsulate one or more CTUs within a slice. The mode selection unit 202 may partition the CTU of the picture according to a tree structure, such as the MTT structure, QTBT structure, superblock structure, or quadtree structure described above. As described above, video encoder 200 may form one or more CUs from partitioning a CTU according to a tree structure. Such CUs may also be generally referred to as “video blocks” or “blocks.”

In general, mode selection unit 202 also controls its components (e.g., motion estimation unit 222, motion compensation unit 224, and intra prediction unit 226) to select the current block (e.g., current CU, Or in HEVC, generate a prediction block for the overlapping part of PU and TU). For inter prediction of the current block, motion estimation unit 222 selects one or more closely matching reference blocks within one or more reference pictures (e.g., one or more previously coded pictures stored in DPB 218). Motion search can also be performed to identify. In particular, the motion estimation unit 222 determines whether potential reference blocks are currently You can also calculate a value indicating how similar it is to a block. Motion estimation unit 222 may generally perform these calculations using sample-by-sample differences between the reference block under consideration and the current block. Motion estimation unit 222 may identify the reference block with the lowest value resulting from these calculations, which represents the reference block that most closely matches the current block.

Motion estimation unit 222 may form one or more motion vectors (MVs) that define positions of reference blocks in reference pictures relative to the position of the current block in the current picture. Motion estimation unit 222 may then provide motion vectors to motion compensation unit 224. For example, for unidirectional inter prediction, motion estimation unit 222 may provide a single motion vector, while for bidirectional inter prediction, motion estimation unit 222 may provide two motion vectors. Motion compensation unit 224 may then use the motion vectors to generate a prediction block. For example, motion compensation unit 224 may use the motion vector to retrieve data in a reference block. As another example, if the motion vector has fractional sample precision, motion compensation unit 224 may interpolate values for the prediction block according to one or more interpolation filters. Additionally, for bidirectional inter prediction, motion compensation unit 224 retrieves data for the two reference blocks identified by the respective motion vectors and, for example, through sample-by-sample averaging or weighted averaging, Data can also be combined.

When performing multi-hypothesis inter prediction, motion estimation unit 222 and motion compensation unit 224 may use data in DPB 218 to generate one or more additional prediction blocks as additional hypotheses for the current block. Additionally, video encoder 200 may be configured to apply any of the various techniques of this disclosure to encode motion information for one or more additional prediction hypotheses.

For example, motion compensation unit 224 may generate both a fundamental mode hypothesis and an additional hypothesis. Motion compensation unit 224 may use unidirectional or bidirectional inter prediction to generate fundamental mode hypotheses. Motion compensation unit 224 may also generate additional hypotheses using unidirectional or bidirectional inter prediction. In some examples, additional hypotheses may be limited to only one-way predictions. According to the techniques of this disclosure, mode selection unit 202 may determine whether to encode motion information for an additional hypothesis using Merge mode or AMVP mode. In response to determining to encode the motion information for the additional hypothesis using merge mode, mode selection unit 202 may include a value in the merge mode syntax element indicating that the motion information for the additional hypothesis is to be encoded using merge mode. You can also allocate and encode motion information using merge mode.

In particular, to encode motion information for additional hypotheses using merge modes, mode selection unit 202 may construct a merge candidate list. That is, the mode selection unit 202 may determine motion information from neighboring blocks for the current block being encoded and add motion information for specific neighboring blocks to the merge candidate list. Mode selection unit 202 may be configured to limit merge candidates to only those that are unidirectional prediction candidates (also referred to as “unidirectional prediction candidates”). If the neighboring block is predicted using bidirectional prediction, mode select unit 202 may generate one or two merge candidates from the neighboring block as discussed above with respect to FIG. 2. For example, mode select unit 202 may construct a first merge candidate from a first set of motion information (e.g., L0 motion information) for a neighboring block and, in some examples, a second set of motion information for a neighboring block. A second merge candidate may be configured from motion information (eg, L1 motion information).

Mode selection unit 202 may also form a merge index with a value indicating which of the merge candidates will be used to encode motion information for the additional hypothesis. In particular, the mode selection unit 202 may determine whether any of the merge candidates in the merge candidate list have motion information that matches the motion information formed by the motion estimation unit 222 for the additional hypothesis. Mode selection unit 202 may select one of the merge candidates in the merge candidate list with matching motion information as a merge candidate to be used to encode motion information for the additional hypothesis.

The motion compensation unit 224 may further combine the base hypothesis with additional hypotheses, for example as an average or weighted combination of each sample on a sample-by-sample basis. After combining the base hypothesis with additional hypotheses, motion compensation unit 224 may provide the resulting prediction block to residual generation unit 204 and reconstruction unit 214.

Additionally or alternatively, mode selection unit 202 may determine whether to apply local illumination compensation (LIC) to additional hypotheses depending on whether LIC was applied to the primary hypothesis. For example, the mode selection unit 202 may determine that LIC will be applied to the additional hypothesis if LIC was applied to the basic hypothesis, otherwise, not to apply LIC. As another example, if LIC was applied to the basic hypothesis and motion information for the additional hypothesis was encoded using AMVP, mode selection unit 202 may determine to perform LIC for the additional hypothesis. Alternatively, if LIC has been applied to the base hypothesis and the motion information for the additional hypothesis has been encoded using merge mode, mode selection unit 202 determines whether to perform LIC on the additional hypothesis and A LIC syntax element (e.g., LIC flag) indicating whether to perform LIC may be encoded.

Additionally or alternatively, mode select unit 202 may determine which of various interpolation filters to use to interpolate the value for the half sample position. In particular, if the motion vector for the basic hypothesis of the previous block is encoded using AMVP with half-sample precision, and if the previous block is selected as a candidate for encoding the motion information of the additional hypothesis, the mode selection unit ( 202) may decide to use a 6-tap interpolation filter to interpolate the values for the half sample positions.

When operating according to the AV1 video coding format, motion estimation unit 222 and motion compensation unit 224 may perform translational motion compensation, affine motion compensation, overlapped block motion compensation (OBMC), and/or complex inter-compensation. may be configured to encode coding blocks (e.g., both luma and chroma coding blocks) of video data using intra prediction.

As another example, for intra prediction or intra prediction coding, intra prediction unit 226 may generate a prediction block from samples neighboring the current block. For example, for directional modes, intra prediction unit 226 may typically generate a prediction block by mathematically combining the values of neighboring samples and populating these calculated values in a defined direction over the current block. It may be possible. As another example, for DC mode, intra prediction unit 226 may calculate the average of neighboring samples for the current block and generate a prediction block to include this resulting average for each sample of the prediction block. .

When operating according to the AV1 video coding format, intra prediction unit 226 may perform directed intra prediction, undirected intra prediction, recursive filter intra prediction, chroma-from-luma (CFL) prediction, intra block copy (IBC), and /or may be configured to encode coding blocks (e.g., both luma and chroma coding blocks) of video data using a color palette mode. Mode selection unit 202 may include additional functional units for performing video prediction according to different prediction modes.

Mode selection unit 202 provides prediction blocks to residual generation unit 204. Residual generation unit 204 receives a raw, unencoded version of the current block from video data memory 230 and a prediction block from mode selection unit 202. The residual generation unit 204 calculates sample-by-sample differences between the current block and the prediction block. The resulting sample-by-sample differences define the residual block for the current block. In some examples, residual generation unit 204 may also determine differences between sample values in a residual block to generate the residual block using residual differential pulse code modulation (RDPCM). In some examples, residual generation unit 204 may be formed using one or more subtractor circuits that perform binary subtraction.

In examples where mode select unit 202 partitions CUs into PUs, each PU may be associated with a luma prediction unit and corresponding chroma prediction units. Video encoder 200 and video decoder 300 may support PUs with various sizes. As indicated above, the size of the CU may refer to the size of the luma coding block of the CU and the size of the PU may refer to the size of the luma prediction block of the PU. Assuming that the size of a specific CU is 2Nx2N, the video encoder 200 supports PU sizes of 2Nx2N or NxN for intra prediction, and supports symmetric PU sizes such as 2Nx2N, 2NxN, Nx2N, NxN, etc. for inter prediction. You can also apply. Video encoder 200 and video decoder 300 may also support asymmetric partitioning for PU sizes of 2NxnU, 2NxnD, nLx2N, and nRx2N for inter prediction.

In examples where mode select unit 202 does not further partition the CU into PUs, each CU may be associated with a luma coding block and corresponding chroma coding blocks. As above, the size of the CU may refer to the size of the luma coding block of the CU. Video encoder 200 and video decoder 300 may support CU sizes of 2Nx2N, 2NxN, or Nx2N.

For other video coding techniques, such as intra block copy mode coding, affine mode coding, and linear model (LM) mode coding, as some examples, mode selection unit 202 can encode, via the respective units associated with the coding techniques, Generates a prediction block for the current block being processed. In some examples, such as palette mode coding, mode selection unit 202 may not generate a prediction block, but instead generate syntax elements indicating how to reconstruct the block based on the selected palette. In these modes, mode select unit 202 may provide these syntax elements to entropy encoding unit 220 to be encoded.

As described above, residual generation unit 204 receives video data for the current block and the corresponding prediction block. Next, the residual generation unit 204 generates a residual block for the current block. To generate a residual block, residual generation unit 204 calculates sample-by-sample differences between the current block and the prediction block.

Transform processing unit 206 applies one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a “transform coefficient block”). Transform processing unit 206 may apply various transforms to the residual block to form a transform coefficient block. For example, transform processing unit 206 may apply a discrete cosine transform (DCT), a directional transform, a Karhunen-Loeve transform (KLT), or a conceptually similar transform to the residual block. In some examples, transform processing unit 206 may perform multiple transforms, such as a first-order transform and a second-order transform, such as a rotation transform, on the residual block. In some examples, transform processing unit 206 does not apply transforms to the residual block.

When operating in accordance with AV1, transform processing unit 206 may apply one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a “transform coefficient block”). Transform processing unit 206 may apply various transforms to the residual block to form a transform coefficient block. For example, transform processing unit 206 may include a discrete cosine transform (DCT), an asymmetric discrete sine transform (ADST), an inverted ADST (e.g., inverse ADST), and a horizontal identity transform (IDTX). You can also apply the /vertical transformation combination. When using an identity transformation, the transformation is skipped in either the vertical or horizontal directions. In some examples, conversion processing may be skipped.

Quantization unit 208 may quantize the transform coefficients in the transform coefficient block to generate a quantized transform coefficient block. Quantization unit 208 may quantize the transform coefficients of the transform coefficient block according to a quantization parameter (QP) value associated with the current block. Video encoder 200 (e.g., via mode select unit 202) may adjust the degree of quantization applied to transform coefficient blocks associated with the current block by adjusting the QP value associated with the CU. Quantization may introduce loss of information, and therefore quantized transform coefficients may have lower precision than the original transform coefficients generated by transform processing unit 206.

The inverse quantization unit 210 and the inverse transform processing unit 212 may apply inverse quantization and inverse transforms to the quantized transform coefficient block, respectively, to restore the residual block from the transform coefficient block. The reconstruction unit 214 may generate a reconstructed block corresponding to the current block (potentially with some degree of distortion) based on the predicted block and the reconstructed residual block generated by the mode select unit 202. . For example, reconstruction unit 214 may add samples of the reconstructed residual block to corresponding samples from a prediction block generated by mode select unit 202 to generate a reconstructed block.

Filter unit 216 may perform one or more filter operations on the reconstructed blocks. For example, filter unit 216 may perform deblocking operations to reduce blockiness artifacts along the edges of CUs. Operations of filter unit 216 may be skipped in some examples.

When operating according to AV1, filter unit 216 may perform one or more filter operations on the reconstructed blocks. For example, filter unit 216 may perform deblocking operations to reduce blockiness artifacts along the edges of CUs. In other examples, filter unit 216 may apply a constrained directional enhancement filter (CDEF), which may be applied after deblocking, and a series of non-separable, non-linear, low-pass directional filters based on the estimated edge directions. May also include application. Filter unit 216 may also include a loop restoration filter applied after CDEF, a separable symmetric normalized Wiener filter or a dual self-inductive filter.

The video encoder 200 stores the reconstructed blocks in the DPB 218. For example, in instances where the operations of filter unit 216 are not performed, reconstruction unit 214 may store the reconstructed blocks in DPB 218. In examples in which the operations of filter unit 216 are performed, filter unit 216 may store the filtered reconstructed blocks in DPB 218 . Motion estimation unit 222 and motion compensation unit 224 may retrieve a reference picture formed from the reconstructed (and potentially filtered) blocks from DPB 218 to inter-predict blocks of subsequently encoded pictures. there is. Additionally, intra prediction unit 226 may use the reconstructed blocks in the DPB 218 of the current picture to intra predict other blocks in the current picture.

In general, entropy encoding unit 220 may entropy encode syntax elements received from other functional components of video encoder 200. For example, entropy encoding unit 220 may entropy encode quantized transform coefficient blocks from quantization unit 208. As another example, entropy encoding unit 220 may entropy encode prediction syntax elements (e.g., motion information for inter prediction or intra mode information for intra prediction) from mode selection unit 202. The entropy encoding unit 220 may perform one or more entropy encoding operations on syntax elements, which are other examples of video data, to generate entropy encoded data. For example, entropy encoding unit 220 may perform context adaptive variable length coding (CAVLC) operations, CABAC operations, variable-to-variable (V2V) length coding operations, syntax-based context-adaptive binary arithmetic coding (SBAC) operations, and probability intervals. A partitioning entropy (PIPE) coding operation, an exponential Golomb encoding operation, or another type of entropy encoding operation may be performed on the data. In some examples, entropy encoding unit 220 may operate in a bypass mode in which syntax elements are not entropy encoded.

The video encoder 200 may output a bitstream containing entropy-encoded syntax elements necessary for reconstructing blocks of a picture or slice. In particular, the entropy encoding unit 220 may output a bitstream.

According to AV1, entropy encoding unit 220 may be configured as a symbol-to-symbol adaptive multi-symbol arithmetic coder. A syntax element in AV1 contains an alphabet of N elements, and the context (eg, a probability model) contains a set of N probabilities. Entropy encoding unit 220 may store probabilities as n-bit (e.g., 15-bit) cumulative distribution functions (CDFs). The entropy encoding unit 220 may perform recursive scaling with an update factor based on the alphabet size to update the contexts.

The operations described above are explained in relation to blocks. Such description should be understood as operations on luma coding blocks and/or chroma coding blocks. As described above, in some examples, the luma coding block and chroma coding blocks are the luma and chroma components of a CU. In some examples, the luma coding block and chroma coding blocks are luma and chroma components of a PU.

In some examples, operations performed on a luma coding block do not need to be repeated for chroma coding blocks. As an example, the operations of identifying the motion vector (MV) and reference picture for a luma coding block do not need to be repeated to identify the MV and reference picture for chroma blocks. Rather, the MV for the luma coding block may be scaled to determine the MV for the chroma blocks, and the reference picture may be the same. As another example, the intra prediction process may be the same for luma coding blocks and chroma coding blocks.

4 is a block diagram illustrating an example video decoder 300 that may perform the techniques of this disclosure. 4 is provided for illustrative purposes and is not limiting to the techniques as broadly illustrated and described in this disclosure. For purposes of explanation, this disclosure describes video decoder 300 according to the techniques of VVC (ITU-T H.266, under development) and HEVC (ITU-T H.265). However, the techniques of this disclosure may be performed by video coding devices configured for other video coding standards.

In the example of Figure 4, video decoder 300 includes a coded picture buffer (CPB) memory 320, an entropy decoding unit 302, a prediction processing unit 304, an inverse quantization unit 306, and an inverse transform processing unit ( 308), a reconstruction unit 310, a filter unit 312, and a decoded picture buffer (DPB) 314. CPB memory 320, entropy decoding unit 302, prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, restoration unit 310, filter unit 312, and DPB 314 ) may be implemented in one or more processors or in processing circuitry. For example, units of video decoder 300 may be implemented as one or more circuits or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Moreover, video decoder 300 may include additional or alternative processors or processing circuitry to perform these and other functions.

Prediction processing unit 304 includes a motion compensation unit 316 and an intra prediction unit 318. Prediction processing unit 304 may include additional units for performing prediction according to different prediction modes. As examples, prediction processing unit 304 may include a palette unit, an intra block copy unit (which may form part of motion compensation unit 316), an affine unit, a linear model (LM) unit, etc. In other examples, video decoder 300 may include more, fewer, or different functional components.

When operating in accordance with AV1, compensation unit 316 may use translational motion compensation, affine motion compensation, OBMC, and/or complex inter-intra prediction as described above to code blocks of video data (e.g., may be configured to decode both luma and chroma coding blocks). Intra prediction unit 318 codes blocks of video data using directed intra prediction, non-directional intra prediction, recursive filter intra prediction, CFL, intra block copy (IBC), and/or color palette modes, as described above. (e.g., both luma and chroma coding blocks).

CPB memory 320 may store video data, such as an encoded video bitstream, to be decoded by components of video decoder 300. Video data stored in CPB memory 320 may be obtained, for example, from computer-readable medium 110 (FIG. 1). CPB memory 320 may include a CPB that stores encoded video data (e.g., syntax elements) from an encoded video bitstream. CPB memory 320 may also store video data other than syntax elements of a coded picture, such as temporary data representing outputs from various units of video decoder 300. DPB 314 generally stores decoded pictures that video decoder 300 may output and/or use as reference video data when decoding subsequent data or pictures of the encoded video bitstream. CPB memory 320 and DPB 314 may be memory devices such as DRAM, including synchronous dynamic random access memory (DRAM) (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. It may be formed by any of a variety of memory devices. CPB memory 320 and DPB 314 may be provided by the same memory device or separate memory devices. In various examples, CPB memory 320 may be on-chip or off-chip relative to other components of video decoder 300.

Additionally or alternatively, in some examples, video decoder 300 may retrieve coded video data from memory 120 (Figure 1). That is, memory 120 may store data as discussed above with CPB memory 320. Likewise, memory 120 may store instructions to be executed by video decoder 300 when some or all of the functionality of video decoder 300 is implemented in software to be executed by the processing circuitry of video decoder 300. .

The various units shown in FIG. 4 are illustrated to aid understanding of operations performed by video decoder 300. Units may be implemented as fixed function circuits, programmable circuits, or a combination thereof. Similar to Figure 3, fixed function circuits refer to circuits that provide specific functionality and are predefined for the operations that can be performed. Programmable circuits refer to circuits that may be programmed to perform various tasks, providing flexible functionality in the operations that may be performed. For example, programmable circuits may execute software or firmware that causes the programmable circuits to operate in a manner defined by instructions in the software or firmware. Fixed function circuits may execute software instructions (eg, to receive parameters or output parameters), but the types of operations they perform are generally invariant. In some examples, one or more of the units may be separate circuit blocks (fixed function or programmable), and in some examples, one or more of the units may be integrated circuits.

Video decoder 300 may include ALUs, EFUs, digital circuits, analog circuits, and/or programmable cores formed from programmable circuits. In examples in which the operations of video decoder 300 are performed by software executing on programmable circuits, on-chip or off-chip memory may store instructions (e.g., objects) of the software that video decoder 300 receives and executes. code) can also be saved.

The entropy decoding unit 302 may receive encoded video data from CPB, and may entropy decode the video data to reproduce syntax elements. The prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the restoration unit 310, and the filter unit 312 process the decoded video data based on syntax elements extracted from the bitstream. You can also create

Generally, the video decoder 300 restores a picture on a block-by-block basis. The video decoder 300 may individually perform a reconstruction operation for each block (here, the block currently being restored, i.e., being decoded, may be referred to as the “current block”).

Entropy decoding unit 302 may entropy decode syntax elements defining quantized transform coefficients of a quantized transform coefficient block, as well as transform information, such as quantization parameter (QP) and/or transform mode indication(s). Inverse quantization unit 306 may use the QP associated with the quantized transform coefficient block to determine the degree of quantization and likewise the degree of inverse quantization that inverse quantization unit 306 will apply. Inverse quantization unit 306 may, for example, perform a bitwise left shift operation to inverse quantize quantized transform coefficients. Thereby, the inverse quantization unit 306 may form a transform coefficient block containing transform coefficients.

After inverse quantization unit 306 forms a transform coefficient block, inverse transform processing unit 308 may apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, inverse transform processing unit 308 may apply an inverse DCT, inverse integer transform, inverse Karhunen-Loeve transform (KLT), inverse rotation transform, inverse directional transform, or other inverse transform to the transform coefficient block.

Additionally, the prediction processing unit 304 generates a prediction block according to prediction information syntax elements entropy decoded by the entropy decoding unit 302. For example, if prediction information syntax elements indicate that the current block is inter-predicted, motion compensation unit 316 may generate a prediction block. In this case, the prediction information syntax elements may represent a reference picture in the DPB 314 from which to search for a reference block, as well as a motion vector that identifies the location of the reference block in the reference picture relative to the location of the current block in the current picture. there is. Motion compensation unit 316 may perform the inter prediction process generally in a manner substantially similar to that described with respect to motion compensation unit 224 (Figure 3).

When performing multi-hypothesis inter prediction, motion compensation unit 316 may use data in DPB 314 to generate one or more additional prediction blocks as additional hypotheses for the current block. Additionally, video decoder 300 may be configured to apply any of the various techniques of this disclosure to decode motion information for one or more additional prediction hypotheses.

For example, motion compensation unit 316 may generate both a fundamental mode hypothesis and an additional hypothesis. Motion compensation unit 316 may use unidirectional or bidirectional inter prediction to generate fundamental mode hypotheses. Motion compensation unit 316 may also generate additional hypotheses using unidirectional or bidirectional inter prediction. In some examples, additional hypotheses may be limited to only one-way predictions. According to the techniques of this disclosure, prediction processing unit 304 may determine whether to encode motion information for the additional hypothesis using Merge mode or AMVP mode. In particular, prediction processing unit 304 receives a value for a merge mode syntax element that indicates whether motion information for additional hypotheses should be decoded using merge mode or AMVP mode, and uses the indicated mode. You can also decode motion information.

To decode motion information for additional hypotheses using merge mode, prediction processing unit 304 may construct a merge candidate list. That is, the prediction processing unit 304 may determine motion information from neighboring blocks for the current block being encoded, and add motion information for specific neighboring blocks to the merge candidate list. Prediction processing unit 304 may be configured to limit merge candidates to only those that are unidirectional prediction candidates (also referred to as “unidirectional prediction candidates”). If the neighboring block is predicted using bi-prediction, prediction processing unit 304 may generate one or two merge candidates from the neighboring block as discussed above with respect to FIG. 2. For example, prediction processing unit 304 may construct a first merge candidate from a first set of motion information (e.g., L0 motion information) for a neighboring block and, in some examples, a second set of motion information for a neighboring block. A second merge candidate may be configured from motion information (eg, L1 motion information).

Prediction processing unit 304 may also form a merge index whose value indicates which of the merge candidates will be used to encode motion information for the additional hypothesis. Prediction processing unit 304 may determine one of the merge candidates in the merge candidate list corresponding to the merge index as the merge candidate to be used to decode the motion information for the additional hypothesis.

The motion compensation unit 316 may further combine the base hypothesis with additional hypotheses, for example as an average or weighted combination of each sample on a sample-by-sample basis. After combining the base hypothesis with additional hypotheses, motion compensation unit 316 may provide the resulting prediction block to reconstruction unit 310.

Additionally or alternatively, prediction processing unit 304 may determine whether to apply local illumination compensation (LIC) to additional hypotheses depending on whether LIC was applied to the base hypothesis. For example, prediction processing unit 304 may determine that LIC will be applied to the additional hypothesis if LIC was applied to the base hypothesis, and not to apply LIC if not. As another example, if LIC was applied to the base hypothesis and the motion information for the additional hypothesis was encoded using AMVP, prediction processing unit 304 may determine to perform LIC for the additional hypothesis. Alternatively, if LIC has been applied to the base hypothesis and the motion information for the additional hypothesis has been decoded using merge mode, prediction processing unit 304 may generate a LIC syntax element indicating whether to perform LIC on the additional hypothesis (e.g., LIC flag) can also be decoded.

Additionally or alternatively, prediction processing unit 304 may determine which of various interpolation filters to use to interpolate the value for the half sample position. In particular, if the motion vector for the base hypothesis of the previous block is encoded using AMVP with half-sample precision, and if the previous block is selected as a candidate for encoding the motion information of the additional hypothesis, the prediction processing unit ( 304) may decide to use a 6-tap interpolation filter to interpolate the values for the half sample positions.

As another example, if the prediction information syntax elements indicate that the current block is intra predicted, intra prediction unit 318 may generate the prediction block according to the intra prediction mode indicated by the prediction information syntax elements. Again, intra prediction unit 318 may perform the intra prediction process generally in a manner substantially similar to that described for intra prediction unit 226 (Figure 3). Intra prediction unit 318 may retrieve data of neighboring samples for the current block from DPB 314.

The restoration unit 310 restores the current block using the prediction block and the residual block. For example, the reconstruction unit 310 may restore the current block by adding samples of the residual pixel block to corresponding samples of the prediction block.

Filter unit 312 may perform one or more filter operations on the reconstructed blocks. For example, filter unit 312 may perform deblocking operations to reduce blockiness artifacts along the edges of reconstructed blocks. The operations of filter unit 312 are not necessarily performed in all examples.

The video decoder 300 may store the reconstructed blocks in the DPB 314. For example, in examples where the operations of filter unit 312 are not performed, reconstruction unit 310 may store the reconstructed blocks in DPB 314. In examples in which the operations of filter unit 312 are performed, filter unit 312 may store the filtered reconstructed blocks in DPB 314. As discussed above, DPB 314 may provide reference information to prediction processing unit 304, such as the current picture for intra prediction and samples of previously decoded pictures for subsequent motion compensation. Moreover, video decoder 300 may output decoded pictures (e.g., decoded video) from DPB 314 for subsequent presentation on a display device, such as display device 118 of FIG. 1.

5 is a flowchart illustrating an example method for encoding a current block in accordance with the techniques of this disclosure. The current block may include the current CU. Although described with respect to video encoder 200 ( FIGS. 1 and 3 ), it should be understood that other devices may be configured to perform methods similar to those of FIG. 5 .

In this example, video encoder 200 first predicts the current block (350). For example, video encoder 200 may form a prediction block for the current block. In particular, the video encoder 200 may form a prediction block using multi-hypothesis inter prediction. Video encoder 200 may then calculate a residual block for the current block (352). To calculate the residual block, video encoder 200 may calculate the difference between the original, uncoded block and the prediction block for the current block. Next, video encoder 200 may transform the residual block and quantize the transform coefficients of the residual block (354). Next, video encoder 200 may scan the quantized transform coefficients of the residual block (356). During or following a scan, video encoder 200 may entropy encode 358 prediction information as well as transform coefficients. For example, video encoder 200 may encode data using CAVLC or CABAC. Video encoder 200 may also encode motion information for one or more additional hypotheses using merge mode according to any of the various techniques of this disclosure. Next, the video encoder 200 may output entropy-encoded data of the block (360).

Video encoder 200 may also perform the current block after encoding the current block to use the decoded version of the current block as reference data for subsequently coded data (e.g., in inter or intra prediction modes). You can also decode blocks. Accordingly, the video encoder 200 may reproduce the residual block by inversely quantizing and inversely transforming the coefficients (362). Video encoder 200 may combine the residual block with the prediction block to form a decoded block (364). In some examples, video encoder 200 may perform local lighting compensation (LIC) according to any of the various techniques of this disclosure. Video encoder 200 may then store the decoded block in DPB 218 (366).

6 is a flow chart illustrating an example method for decoding a current block of video data in accordance with the techniques of this disclosure. The current block may include the current CU. Although described with respect to video decoder 300 ( FIGS. 1 and 4 ), it should be understood that other devices may be configured to perform methods similar to those of FIG. 6 .

Video decoder 300 may receive entropy encoded data for the current block, such as entropy encoded data and entropy encoded prediction information for transform coefficients of the residual block corresponding to the current block (370). The video decoder 300 may entropy decode the entropy encoded data, determine prediction information for the current block, and reproduce transform coefficients of the residual block (372). For example, video decoder 300 may entropy decode motion information for one or more additional prediction hypotheses in merge mode using any of the various techniques of this disclosure. Video decoder 300 may predict the current block, for example, using an intra or inter prediction mode as indicated by the prediction information for the current block to calculate a prediction block for the current block (374) . Video decoder 300 may then backscan the reproduced transform coefficients to generate a block of quantized transform coefficients (376). Next, the video decoder 300 may inverse quantize the transform coefficients and apply an inverse transform to the transform coefficients to generate a residual block (378). Video decoder 300 may finally decode the current block by combining the prediction block and the residual block (380). In some examples, video decoder 300 may further perform local illumination compensation (LIC) on a decoded block according to any of the various techniques of this disclosure.

7 is a flow chart illustrating an example method of decoding video data according to the techniques of this disclosure. The method of FIG. 7 may also be performed by a video encoder such as video encoder 200 of FIGS. 1 and 3. When performed as part of a video encoding process, the method of FIG. 7 may correspond to steps 350 and 362 through 364 of FIG. 5. The method of FIG. 7 may also be performed by a video decoder such as video decoder 300 of FIGS. 1 and 4. When performed as part of a video decoding process, the method of Figure 7 may correspond to steps 374 and 380 of Figure 6. Although the method of Figure 7 is described as a method of decoding video data, the video encoder both encodes and decodes the video data for use as subsequent prediction data, as described above. Accordingly, the method of Figure 7 may be performed by both video encoders and video decoders. For example purposes, the method of FIG. 7 is described with respect to video decoder 300, but certain aspects are also described with respect to video encoder 200.

Initially, video decoder 300 may form a basic hypothesis prediction block for the current block of video data (400). For example, video decoder 300 may perform unidirectional prediction (using a single set of motion information) or bidirectional prediction (using two sets of motion information) to form a base hypothesis prediction block. .

Video decoder 300 may also code (i.e., decode) merge mode syntax elements for additional hypothetical blocks to the current block (402). The value of the merge mode syntax element may indicate whether the motion information for the additional hypothetical block is coded using merge mode or AMVP mode. When performed by video encoder 200, video encoder 200 may encode the value of the merge mode syntax element.

If the merge mode syntax element indicates that motion information for the additional hypothetical block is predicted using merge mode, video decoder 300 may form a merge candidate list (404). The merge candidate list may correspond to merge candidates indicating motion information of neighboring blocks for the current block. The video decoder 300 may ensure that each merge candidate in the merge candidate list includes only unidirectional motion information. If the motion information for one of the neighboring blocks is bi-predictively coded, the video decoder 300 generates one or two merge candidates from one of the neighboring blocks, e.g., a single merge candidate containing one of the two sets of motion information. , or forming a first merge candidate including one of the two sets of motion information (e.g., L0 motion information) and a second merge candidate including the other of the two sets of motion information (e.g., L1 motion information). You may. In this way, each merge candidate in the merge candidate list may be limited to one-way prediction.

The video decoder 300 may then code motion information for additional hypothetical blocks (406). For example, assuming that motion information for an additional hypothesis block is coded in merge mode, the video decoder 300 may decode a merge index that identifies one of the merge candidates in the merge candidate list. The video decoder 300 may then form an additional hypothesis block using the identified one of the merge candidates as motion information. On the other hand, if motion information for an additional hypothesis block is coded in AMVP mode, the video decoder 300 may decode the AMVP candidate index, reference picture list identifier, reference picture index, and motion vector difference information. Alternatively, when the method is performed by video encoder 200, video encoder 200 may encode a merge index or AMVP candidate index, a reference picture list identifier, a reference picture index, and motion vector difference information.

The video decoder 300 may then generate an additional hypothesis block using the motion information (408). Video decoder 300 may further form a multi-hypothesis prediction block from the basic hypothesis prediction block and additional hypothesis blocks (410). For example, video decoder 300 may average the collocated samples of the basic hypothesis prediction block and the additional hypothesis block or perform a weighted combination of the collocated samples of the basic hypothesis prediction block and the additional hypothesis block. In some examples, video decoder 300 may also perform local illumination compensation (LIC) on either or both the basic hypothesis block and/or the additional hypothesis block before forming the multi-hypothesis prediction block.

Finally, video decoder 300 may decode (i.e., play) the current block using the multi-hypothesis prediction block (412). For example, the video decoder 300 may decode the quantized transform coefficients for the current block, inversely quantize and transform the quantized transform coefficients to form residual samples, and inversely scan the residual samples to reproduce the residual block. . The video decoder 300 may then combine the residual block and the multi-hypothesis prediction block on a sample-by-sample basis to restore (decode) the current block.

In this way, the method of Figure 7 represents an example of a method for decoding (and/or encoding) video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. coding the merge mode syntax element, indicating whether it is coded; Coding motion information for the second prediction block according to a merge mode syntax element, wherein the motion information for the second prediction block is encoded in the merge mode syntax element. When indicating that it is coded using , forming a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of uni-prediction motion information. Coding motion information for a prediction block; generating a second prediction block for the current block of video data using motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Various examples of the techniques of this disclosure are summarized in the following provisions:

Clause 1: A method of decoding video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; generating a second prediction block for the current block of video data as an additional prediction hypothesis; determining whether to apply local lighting compensation (LIC) to a second prediction block depending on whether LIC has been applied to the first prediction block; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 2: The method of Clause 1, wherein the default inter prediction mode includes one of one-way inter prediction or two-way inter prediction.

Clause 3: The clause of any of clauses 1 and 2, further comprising applying the LIC to the first prediction block, wherein determining whether to apply the LIC to the second prediction block comprises applying the LIC to the first prediction block. The method comprising determining to apply LIC to the second prediction block in response to applying .

Clause 4: The method of any of clauses 1 and 2, comprising: applying LIC to the first prediction block; and coding motion information for a second prediction block using an advanced motion vector prediction (AMVP) mode, wherein determining whether to apply LIC to the second prediction block comprises: Applying LIC to and determining to apply LIC to the second prediction block in response to coding motion information for the second prediction block using AMVP mode.

Clause 5: The method of any of clauses 1 and 2, comprising: applying LIC to the first prediction block; and coding motion information for the second prediction block using a merge mode, wherein determining whether to apply LIC to the second prediction block includes: coding the LIC flag; and determining whether to apply LIC to the second prediction block according to the value of the LIC flag for the merge candidate of the second prediction block.

Clause 6: A method of decoding video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. coding the merge mode syntax element, indicating whether it is coded; coding motion information for the second prediction block according to a merge mode syntax element; generating a second prediction block for the current block of video data using motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 7: A method of coding video data, comprising a combination of the method of any of clauses 1 to 5 and the method of clause 6.

Clause 8: The clause of any of clauses 6 and 7, wherein if the merge mode syntax element indicates that merge mode is used, coding the motion information for the second prediction block comprises: A method comprising coding a merge index indicating a merge candidate to inherit.

Clause 9: The clauses of any of clauses 6 and 7, wherein if the merge mode syntax element indicates that merge mode is not used, then coding the motion information for the second prediction block comprises: A method comprising coding a reference picture index, a motion vector predictor index, and a motion vector difference.

Clause 10: The method of any of clauses 6 to 9, wherein coding the motion information for the second prediction block comprises forming a merge candidate list comprising one or more merge candidates, each of the merge candidates comprising: A method representing respective sets of one-way predictive motion information.

Clause 11: The clause 10, wherein the second prediction block includes one additional motion hypothesis among the plurality of additional motion hypotheses, and the method further comprises coding motion information for each of the additional motion hypotheses using the same merge candidate list. A method comprising further steps.

Clause 12: The clause of any of clauses 10 and 11, wherein forming the merge candidate list comprises forming the merge candidate list according to a merge candidate list construction process in geometric partitioning mode (GPM). method.

Clause 13: The method of any of clauses 6-9, wherein the second prediction block comprises one additional motion hypothesis among a plurality of additional motion hypotheses, and coding motion information for the second prediction block comprises: forming a merge candidate list including two or more merge candidates; selecting one of the merge candidates from the merge candidate list for motion information for the second prediction block; and coding motion information for a second prediction block using said one of the merge candidates, the method comprising: removing said one of the merge candidates from a merge candidate list to form a reduced merge candidate list; and coding motion information for the third prediction block using one of the remaining merge candidates in the reduced merge candidate list.

Clause 14: The clause 13, wherein coding a first merge candidate index for a second prediction block, wherein the merge candidate list has N merge candidates, N is a positive integer greater than 1, and the first merge candidate coding the first merge candidate index, wherein the index has N maximum possible truncated binary values; and coding a second merge candidate index for the third prediction block, wherein the reduced merge candidate list has N-1 merge candidates, and the second merge candidate index has N-1 maximum possible truncated binary values. The method further comprising coding the second merge candidate index, having:

Clause 15: The method of any of clauses 6-14, wherein the merge mode syntax element comprises a merge mode syntax element for a primary inter prediction mode of the first prediction block.

Clause 16: The method of any of clauses 6 through 14, wherein the merge mode syntax element comprises a second merge mode syntax element, and the method comprises a first merge mode syntax element for a basic inter prediction mode of the first prediction block. The method further comprising coding, wherein the second merge mode syntax element is different from the first merge mode syntax element.

Clause 17: The clause 16, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and a second A method, wherein coding the merge mode syntax element includes coding a second merge mode syntax element using the first CABAC context in response to coding the first merge mode syntax element using the first CABAC context.

Clause 18: The method of clause 17, wherein the first CABAC context is a CABAC context used for merge mode.

Clause 19: The method of Clause 17, wherein the first CABAC context is different from the second CABAC context used for merge mode.

Clause 20: The method of clause 16, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and The method of claim 2, wherein coding the merge mode syntax element includes coding the second merge mode syntax element using a second CABAC context.

Clause 21: The method of clause 20, wherein the second CABAC context is different from the first CABAC context.

Clause 22: The method of any of clauses 6-21, wherein the method comprises: coding the motion information of the third prediction block using an advanced motion vector prediction (AMVP) mode, wherein the motion information of the third prediction block is: The coding step includes coding a motion vector difference (MVD) value with half luma sample resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block. coding motion information; and coding a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein generating the second prediction block comprises: generating the second prediction block using a 6-tap interpolation filter; Interpolating half-pixel samples of a reference block for .

Clause 23: A method of decoding video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; generating a second prediction block for the contemporary block of video data as an additional prediction hypothesis; determining whether to apply local lighting compensation (LIC) to a second prediction block depending on whether LIC has been applied to the first prediction block; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 24: The method of clause 23, wherein the default inter prediction mode comprises one of one-way inter prediction or two-way inter prediction.

Clause 25: The method of clause 23, further comprising applying LIC to the first prediction block, wherein determining whether to apply LIC to the second prediction block is performed by the second prediction block in response to applying the LIC to the first prediction block. A method comprising determining to apply LIC to a prediction block.

Clause 26: The method of clause 23, comprising: applying LIC to the first prediction block; and coding motion information for a second prediction block using an advanced motion vector prediction (AMVP) mode, wherein determining whether to apply LIC to the second prediction block comprises: Applying LIC to and determining to apply LIC to the second prediction block in response to coding motion information for the second prediction block using AMVP.

Clause 27: The method of clause 23, comprising: applying LIC to the first prediction block; and coding motion information for the second prediction block using a merge mode, wherein determining whether to apply LIC to the second prediction block includes: coding the LIC flag; and determining whether to apply LIC to the second prediction block according to the value of the LIC flag for the merge candidate of the second prediction block.

Clause 28: A method of decoding video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. coding the merge mode syntax element, indicating whether it is coded; coding motion information for the second prediction block according to a merge mode syntax element; generating a second prediction block for the current block of video data using motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 29: The method of clause 28, wherein if the merge mode syntax element indicates that a merge mode is used, coding the motion information for the second prediction block indicates a merge candidate to inherit the motion information for the second prediction block. A method comprising coding a merge index.

Clause 30: The method of clause 28, wherein if the merge mode syntax element indicates that merge mode is not used, coding motion information for the second prediction block comprises: a reference picture index for the second prediction block, a motion vector prediction A method comprising coding the ruler index and the motion vector difference.

Clause 31: The method of clause 28, wherein coding the motion information for the second prediction block includes forming a merge candidate list including one or more merge candidates, each of the merge candidates being a respective one of the one-way prediction motion information. A method of representing sets.

Clause 32: The clause 31, wherein the second prediction block includes one additional motion hypothesis among the plurality of additional motion hypotheses, and the method further comprises coding motion information for each of the additional motion hypotheses using the same merge candidate list. A method comprising further steps.

Clause 33: The method of clause 31, wherein forming the merge candidate list includes forming the merge candidate list according to a merge candidate list construction process in geometric partitioning mode (GPM).

Clause 34: The method of clause 28, wherein the second prediction block includes one additional motion hypothesis among the plurality of additional motion hypotheses, and coding the motion information for the second prediction block comprises: comprising two or more merge candidates. forming a merge candidate list; selecting one of the merge candidates from the merge candidate list for motion information for the second prediction block; and coding motion information for a second prediction block using said one of the merge candidates, the method comprising: removing said one of the merge candidates from a merge candidate list to form a reduced merge candidate list; and coding motion information for the third prediction block using one of the remaining merge candidates in the reduced merge candidate list.

Clause 35: The clause 34, wherein coding a first merge candidate index for a second prediction block, wherein the merge candidate list has N merge candidates, N is a positive integer greater than 1, and the first merge candidate coding the first merge candidate index, wherein the index has N maximum possible truncated binary values; and coding a second merge candidate index for the third prediction block, wherein the reduced merge candidate list has N-1 merge candidates, and the second merge candidate index has N-1 maximum possible truncated binary values. The method further comprising coding the second merge candidate index, having:

Clause 36: The method of clause 28, wherein the merge mode syntax element comprises a merge mode syntax element for a primary inter prediction mode of the first prediction block.

Clause 37: The method of clause 28, wherein the merge mode syntax element comprises a second merge mode syntax element, and the method further comprises coding the first merge mode syntax element for a primary inter prediction mode of the first prediction block, , wherein the second merge mode syntax element is different from the first merge mode syntax element.

Clause 38: The clause 37, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and a second A method, wherein coding the merge mode syntax element includes coding a second merge mode syntax element using the first CABAC context in response to coding the first merge mode syntax element using the first CABAC context.

Clause 39: The method of clause 38, wherein the first CABAC context is a CABAC context used for merge mode.

Clause 40: The method of clause 38, wherein the first CABAC context is different from the second CABAC context used for merge mode.

Clause 41: The clause 37, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and The method of claim 2, wherein coding the merge mode syntax element includes coding the second merge mode syntax element using a second CABAC context.

Clause 42: The method of clause 41, wherein the second CABAC context is different from the first CABAC context.

Clause 43: The method of clause 28, wherein: coding the motion information of the third prediction block using an advanced motion vector prediction (AMVP) mode, wherein coding the motion information of the third prediction block comprises: half luma coding motion information of a third prediction block, comprising coding a motion vector difference (MVD) value with sample resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block to the current block; and coding a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein generating the second prediction block comprises: generating the second prediction block using a 6-tap interpolation filter; Interpolating half-pixel samples of a reference block for .

Clause 44: The method of any of clauses 1-43, further comprising encoding the current block prior to decoding the current block.

Clause 45: A device for decoding video data, the device comprising one or more means for performing the method of any of clauses 1 to 44.

Clause 46: The device of clause 45, wherein the one or more means comprises one or more processors implemented in circuitry.

Clause 47: The device of any of clauses 45 and 46, further comprising a display configured to display decoded video data.

Clause 48: The device of any of clauses 45-47, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set top box.

Clause 49: The device of clauses 45-48, further comprising a memory configured to store video data.

Clause 50: A computer-readable storage medium storing instructions that, when executed, cause a processor of a device for decoding video data to perform the method of any of clauses 1-44. storage media.

Clause 51: A device for decoding video data, comprising: means for generating a first prediction block for a current block of video data using a basic inter prediction mode; means for generating a second prediction block for the current block of video data as an additional prediction hypothesis; means for determining whether to apply local lighting compensation (LIC) to a second prediction block depending on whether LIC has been applied to the first prediction block; means for forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and means for decoding the current block using the multiple hypothesis prediction block.

Clause 52: A device for decoding video data, comprising: means for generating a first prediction block for a current block of video data using a basic inter prediction mode; As a means for coding a merge mode syntax element for a second prediction block, the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. means for coding the merge mode syntax element, indicating whether the merge mode syntax element is coded; means for coding motion information for the second prediction block according to a merge mode syntax element; means for generating a second prediction block for a current block of video data using motion information; means for forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and means for decoding the current block using the multiple hypothesis prediction block.

Clause 53: A method of decoding video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. coding a merge mode syntax element, indicating whether to be coded; Coding motion information for the second prediction block according to a merge mode syntax element, wherein the motion information for the second prediction block is encoded in the merge mode syntax element. When indicating that it is coded using , forming a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. coding; generating a second prediction block for the current block of video data using motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 54: The clause 53, wherein if the merge mode syntax element indicates that a merge mode is used, coding the motion information for the second prediction block comprises selecting a merge candidate to inherit the motion information for the second prediction block. A method comprising coding a merge index to indicate.

Clause 55: The method of clause 53, wherein if the merge mode syntax element indicates that merge mode is not used, coding motion information for the second prediction block comprises: a reference picture index for the second prediction block, a motion vector A method comprising coding a predictor index and a motion vector difference.

Clause 56: The clause 53, wherein forming a merge candidate list comprises: determining that a neighboring block for the second prediction block is bi-directionally predicted using the first motion information and the second motion information; and forming at least one unidirectional prediction merge candidate from the neighboring block, wherein forming the at least one unidirectional prediction merge candidate includes only one of the first motion information or the second motion information for the at least one unidirectional prediction merge candidate. A method comprising forming the at least one one-way prediction merge candidate, comprising selecting .

Clause 57: The method of clause 56, wherein forming the merge candidate list comprises: forming a first one-way prediction merge candidate using first motion information; and forming a second one-way prediction merge candidate using the second motion information.

Clause 58: The clause 53, wherein the second prediction block includes one additional motion hypothesis among the plurality of additional motion hypotheses, and the method further comprises coding motion information for each of the additional motion hypotheses using the same merge candidate list. A method comprising further steps.

Clause 59: The method of clause 53, wherein forming the merge candidate list includes forming the merge candidate list according to a merge candidate list construction process in geometric partitioning mode (GPM).

Clause 60: The clause 53, wherein the second prediction block includes one additional prediction hypothesis among the plurality of additional motion hypotheses, and coding the motion information for the second prediction block comprises: including two or more merge candidates. forming a merge candidate list; selecting one of the merge candidates from the merge candidate list for motion information for the second prediction block; and coding motion information for a second prediction block using said one of the merge candidates, the method comprising: removing said one of the merge candidates from a merge candidate list to form a reduced merge candidate list; and coding motion information for the third prediction block using one of the remaining merge candidates in the reduced merge candidate list.

Clause 61: The clause 60, wherein coding a first merge candidate index for a second prediction block, wherein the merge candidate list has N merge candidates, N is a positive integer greater than 1, and the first merge candidate coding the first merge candidate index, wherein the index has N maximum possible truncated binary values; and coding a second merge candidate index for the third prediction block, wherein the reduced merge candidate list has N-1 merge candidates, and the second merge candidate index has N-1 maximum possible truncated binary values. The method further comprising coding the second merge candidate index, having:

Clause 62: The method of clause 53, wherein the merge mode syntax element comprises a merge mode syntax element for a primary inter prediction mode of the first prediction block.

Clause 63: The clause 53, wherein the merge mode syntax element comprises a second merge mode syntax element, and the method further comprises coding the first merge mode syntax element for a primary inter prediction mode of the first prediction block, and , wherein the second merge mode syntax element is different from the first merge mode syntax element.

Clause 64: The clause 63, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and a second A method, wherein coding the merge mode syntax element includes coding a second merge mode syntax element using the first CABAC context in response to coding the first merge mode syntax element using the first CABAC context.

Clause 65: The method of clause 64, wherein the first CABAC context is a CABAC context used for merge mode.

Clause 66: The method of clause 64, wherein the first CABAC context is different from the second CABAC context used for merge mode.

Clause 67: The clause 63, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and The method of claim 2, wherein coding the merge mode syntax element includes coding the second merge mode syntax element using a second CABAC context.

Clause 68: The method of clause 67, wherein the second CABAC context is different from the first CABAC context.

Clause 69: The method of clause 53, wherein coding the motion information of the third prediction block using an advanced motion vector prediction (AMVP) mode, wherein coding the motion information of the third prediction block comprises half luma sample resolution. Coding a motion vector difference (MVD) value having a motion vector difference (MVD) value, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block; and coding a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein generating the second prediction block comprises: second prediction using a 6-tap interpolation filter; A method comprising interpolating half-pixel samples of a reference block for the block.

Clause 70: The method of clause 53, further comprising determining whether to apply local lighting compensation (LIC) to the second prediction block depending on whether LIC was applied to the first prediction block.

Clause 71: The method of clause 70, wherein the default inter prediction mode comprises one of one-way inter prediction or two-way inter prediction.

Clause 72: The clause 70, further comprising applying the LIC to the first prediction block, wherein determining whether to apply the LIC to the second prediction block is performed by the second prediction block in response to applying the LIC to the first prediction block. A method comprising determining to apply LIC to a prediction block.

Clause 73: The method of clause 70, comprising: applying LIC to the first prediction block; and coding motion information for a second prediction block using an advanced motion vector prediction (AMVP) mode, wherein determining whether to apply LIC to the second prediction block comprises: Applying LIC to and determining to apply LIC to the second prediction block in response to coding motion information for the second prediction block using AMVP.

Clause 74: The method of clause 70, comprising: applying LIC to the first prediction block; and coding motion information for the second prediction block using a merge mode, wherein determining whether to apply LIC to the second prediction block includes: coding the LIC flag; and determining whether to apply LIC to the second prediction block according to the value of the LIC flag for the merge candidate of the second prediction block.

Clause 75: The method of clause 53, further comprising encoding the current block before decoding the current block.

Clause 76: A device for decoding video data, comprising: a memory configured to store video data; and one or more processors implemented in circuitry, wherein the one or more processors: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element is such that motion information for the second prediction block is coded using merge mode. code the merge mode syntax element to indicate whether to do so; coding the motion information for the second prediction block according to the merge mode syntax element, wherein to code the motion information, the one or more processors may configure the merge mode syntax element to cause the motion information for the second prediction block to use merge mode. when indicating coded, is configured to form a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information, coding the motion information; generate a second prediction block for the current block of video data using the motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 77: The clause 76 of clause 76, wherein to form a merge candidate list, the one or more processors: determine that a neighboring block for a second prediction block is bi-directionally predicted using first motion information and second motion information; and forming at least one unidirectional prediction merge candidate from a neighboring block, wherein the one or more processors are configured to select only one of the first motion information or the second motion information for the at least one unidirectional prediction merge candidate. A device configured to form a one-way prediction merge candidate.

Clause 78: The clause 77, wherein to form a merge candidate list, the one or more processors: use first motion information to form a first one-way predictive merge candidate; and form a second one-way prediction merge candidate using the second motion information.

Clause 79: The method of clause 76, wherein the one or more processors further: code the motion information of the third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, wherein: , the one or more processors are configured to code a motion vector difference (MVD) value with half luma sample resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block. coding information; configured to code a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein to generate the second prediction block, the one or more processors use a 6-tap interpolation filter to A device configured to interpolate half-pixel samples of a reference block for .

Clause 80: The device of clause 76, wherein the one or more processors are configured to determine whether to apply local lighting compensation (LIC) to the second prediction block depending on whether LIC was applied to the first prediction block.

Clause 81: The device of clause 76, wherein the one or more processors are further configured to encode the current block before decoding the current block.

Clause 82: The device of clause 76, further comprising a display configured to display decoded video data.

Clause 83: The device of clause 76, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set top box.

Clause 84: A computer readable storage medium having stored thereon instructions that, when executed, cause a processor to: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. code the merge mode syntax element, indicating whether to code; By coding the motion information for the second prediction block according to the merge mode syntax element, coding the motion information for the second prediction block means that the merge mode syntax element causes the motion information for the second prediction block to be in merge mode. When indicating that it is coded using, forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information, motion information for the second prediction block. Let them code; generate a second prediction block for the current block of video data using the motion information; form a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multiple hypothesis prediction block.

Clause 85: The clause 84 of clause 84, wherein the instructions causing the processor to form a merge candidate list further cause the processor to: determine that a neighboring block to the second prediction block is bi-directionally predicted using the first motion information and the second motion information. to do; and forming at least one one-way prediction merge candidate from a neighboring block, comprising instructions that cause the processor to select only one of the first motion information or the second motion information for the at least one one-way prediction merge candidate, A computer-readable storage medium comprising instructions for forming the at least one one-way predictive merge candidate.

Clause 86: The clause 85, wherein the instructions causing the processor to form a merge candidate list further cause the processor to: form a first one-way predictive merge candidate using first motion information; and instructions for forming a second one-way predictive merge candidate using the second motion information.

Clause 87: The clause 84 of clause 84, further comprising: causing the processor to: code the motion information of the third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, wherein: cause the processor to code the motion information of the third prediction block. The instructions include instructions that cause a processor to code a motion vector difference (MVD) value with half luma sample resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block to the current block. coding the motion information of the block; and further include instructions for causing the processor to code a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein the instructions for causing the processor to generate the second prediction block are to cause the processor to perform 6-tap interpolation. A computer-readable storage medium comprising instructions for interpolating half-pixel samples of a reference block to a second prediction block using a filter.

Clause 88: The computer of clause 84, further comprising instructions that cause the processor to determine whether to apply local illumination compensation (LIC) to the second prediction block depending on whether LIC was applied to the first prediction block. Readable storage medium.

Clause 89: The computer-readable storage medium of clause 84, further comprising instructions to cause the processor to encode the current block prior to decoding the current block.

Clause 90: A device for decoding video data, comprising: means for generating a first prediction block for a current block of video data using a basic inter prediction mode; As a means for coding a merge mode syntax element for a second prediction block, the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. means for coding the merge mode syntax element, indicating whether the merge mode syntax element is coded; Means for coding motion information for a second prediction block according to a merge mode syntax element, wherein the merge mode syntax element includes motion information for the second prediction block. When indicating that it is coded using a merge mode, means for forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. means for coding motion information for; means for generating a second prediction block for a current block of video data using motion information; means for forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and means for decoding the current block using the multiple hypothesis prediction block.

Clause 91: A method of decoding video data, comprising: generating a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. coding the merge mode syntax element, indicating whether it is coded; Coding motion information for the second prediction block according to a merge mode syntax element, wherein the motion information for the second prediction block is encoded in the merge mode syntax element. When indicating that it is coded using , forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. coding information; generating a second prediction block for the current block of video data using motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 92: The clause 91, wherein if the merge mode syntax element indicates that merge mode is used, then coding motion information for the second prediction block comprises selecting a merge candidate to inherit the motion information for the second prediction block. A method comprising coding a merge index to indicate.

Clause 93: The clause of any of clauses 91 and 92, wherein if the merge mode syntax element indicates that merge mode is not used, coding the motion information for the second prediction block comprises: A method comprising coding a reference picture index, a motion vector predictor index, and a motion vector difference.

Clause 94: The method of any of clauses 91-93, wherein forming the merge candidate list comprises: determining that a neighboring block for the second prediction block is bi-directionally predicted using the first motion information and the second motion information. step; and forming at least one unidirectional prediction merge candidate from the neighboring block, wherein forming the at least one unidirectional prediction merge candidate includes only one of the first motion information or the second motion information for the at least one unidirectional prediction merge candidate. A method comprising forming the at least one one-way prediction merge candidate, comprising selecting .

Clause 95: The clause 94, wherein forming the merge candidate list comprises: forming a first one-way prediction merge candidate using first motion information; and forming a second one-way prediction merge candidate using the second motion information.

Clause 96: The method of any of clauses 91-95, wherein the second prediction block includes one additional motion hypothesis from a plurality of additional motion hypotheses, and the method comprises merging each of the additional motion hypotheses using the same merge candidate list. A method further comprising coding motion information for.

Clause 97: The method of any of clauses 91-96, wherein forming the merge candidate list comprises forming the merge candidate list according to a merge candidate list construction process in geometric partitioning mode (GPM). method.

Clause 98: The method of any of clauses 91-97, wherein the second prediction block comprises one additional prediction hypothesis among a plurality of additional motion hypotheses, and coding motion information for the second prediction block comprises: forming a merge candidate list including two or more merge candidates; selecting one of the merge candidates from the merge candidate list for motion information for the second prediction block; and coding motion information for a second prediction block using said one of the merge candidates, the method comprising: removing said one of the merge candidates from a merge candidate list to form a reduced merge candidate list; and coding motion information for the third prediction block using one of the remaining merge candidates in the reduced merge candidate list.

Clause 99: The clause 98, wherein coding a first merge candidate index for a second prediction block, wherein the merge candidate list has N merge candidates, N is a positive integer greater than 1, and the first merge candidate coding the first merge candidate index, wherein the index has N maximum possible truncated binary values; and coding a second merge candidate index for the third prediction block, wherein the reduced merge candidate list has N-1 merge candidates, and the second merge candidate index has N-1 maximum possible truncated binary values. The method further comprising coding the second merge candidate index, having:

Clause 100: The method of any of clauses 91-99, wherein the merge mode syntax element comprises a merge mode syntax element for a primary inter prediction mode of the first prediction block.

Clause 101: The method of any of clauses 91-100, wherein the merge mode syntax element comprises a second merge mode syntax element, and the method comprises a first merge mode syntax element for a basic inter prediction mode of the first prediction block. The method further comprising coding, wherein the second merge mode syntax element is different from the first merge mode syntax element.

Clause 102: The clause 101, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and a second A method, wherein coding the merge mode syntax element includes coding a second merge mode syntax element using the first CABAC context in response to coding the first merge mode syntax element using the first CABAC context.

Clause 103: The method of clause 102, wherein the first CABAC context is a CABAC context used for merge mode.

Clause 104: The method of clause 102, wherein the first CABAC context is different from the second CABAC context used for merge mode.

Clause 105: The clause 101, wherein coding the first merge mode syntax element comprises coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and The method of claim 2, wherein coding the merge mode syntax element includes coding the second merge mode syntax element using a second CABAC context.

Clause 106: The method of clause 105, wherein the second CABAC context is different from the first CABAC context.

Clause 107: The method of any of clauses 91-106, wherein coding the motion information of the third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, comprising: coding the motion information of the third prediction block. , comprising coding a motion vector difference (MVD) value with half luma sample resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block, the motion information of the third prediction block. coding step; and coding a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein generating the second prediction block comprises: second prediction using a 6-tap interpolation filter; A method comprising interpolating half-pixel samples of a reference block for the block.

Clause 108: The method of any of clauses 91-107, further comprising determining whether to apply local lighting compensation (LIC) to the second prediction block depending on whether LIC was applied to the first prediction block. , method.

Clause 109: The method of clause 108, wherein the default inter prediction mode comprises one of one-way inter prediction or two-way inter prediction.

Clause 110: The clause of any of clauses 108 and 109, further comprising applying the LIC to the first prediction block, wherein determining whether to apply the LIC to the second prediction block comprises applying the LIC to the first prediction block. The method comprising determining to apply LIC to the second prediction block in response to applying .

Clause 111: The method of any of clauses 108-110, comprising: applying LIC to the first prediction block; and coding motion information for a second prediction block using an advanced motion vector prediction (AMVP) mode, wherein determining whether to apply LIC to the second prediction block comprises: Applying LIC to and determining to apply LIC to the second prediction block in response to coding motion information for the second prediction block using AMVP.

Clause 112: The method of any of clauses 108-111, comprising: applying LIC to the first prediction block; and coding motion information for the second prediction block using a merge mode, wherein determining whether to apply LIC to the second prediction block includes: coding the LIC flag; and determining whether to apply LIC to the second prediction block according to the value of the LIC flag for the merge candidate of the second prediction block.

Clause 113: The method of any of clauses 91-112, further comprising encoding the current block prior to decoding the current block.

Article 114: A device for decoding video data, comprising: a memory configured to store video data; and one or more processors implemented in circuitry, wherein the one or more processors: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element is such that motion information for the second prediction block is coded using merge mode. code the merge mode syntax element to indicate whether to do so; coding the motion information for the second prediction block according to the merge mode syntax element, wherein to code the motion information, the one or more processors may configure the merge mode syntax element to cause the motion information for the second prediction block to use merge mode. when indicating coded, is configured to form a merge candidate list including one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information, coding the motion information; generate a second prediction block for the current block of video data using the motion information; forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multi-hypothesis prediction block.

Clause 115: The clause 114 of clause 114, wherein to form a merge candidate list, the one or more processors: determine that a neighboring block for a second prediction block is bi-directionally predicted using first motion information and second motion information; and forming at least one unidirectional prediction merge candidate from a neighboring block, wherein the one or more processors are configured to select only one of the first motion information or the second motion information for the at least one unidirectional prediction merge candidate. A device configured to form a one-way prediction merge candidate.

Clause 116: The clause 115 of clause 115, wherein to form a merge candidate list, the one or more processors: use first motion information to form a first one-way predictive merge candidate; and form a second one-way prediction merge candidate using the second motion information.

Clause 117: The clause of any of clauses 114-116, wherein the one or more processors further: code motion information of the third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, wherein the third prediction block: To code motion information, the one or more processors are configured to code a motion vector difference (MVD) value with half luma sample resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block, coding motion information of the third prediction block; configured to code a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein to generate the second prediction block, the one or more processors use a 6-tap interpolation filter to A device configured to interpolate half-pixel samples of a reference block for .

Clause 118: The clauses of any of clauses 114-117, wherein the one or more processors determine whether to apply local lighting compensation (LIC) to a second prediction block depending on whether LIC was applied to the first prediction block. A device configured to:

Clause 119: The device of any of clauses 114-118, wherein the one or more processors are further configured to encode the current block before decoding the current block.

Clause 120: The device of any of clauses 114-119, further comprising a display configured to display decoded video data.

Clause 121: The device of any of clauses 114-120, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set top box.

Clause 122: A computer-readable storage medium having stored thereon instructions that, when executed, cause a processor to: generate a first prediction block for a current block of video data using a basic inter prediction mode; Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block uses merge mode. code the merge mode syntax element, indicating whether to code; By coding the motion information for the second prediction block according to the merge mode syntax element, coding the motion information for the second prediction block means that the merge mode syntax element causes the motion information for the second prediction block to be in merge mode. When indicating that it is coded using, forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information, motion information for the second prediction block. Let them code; generate a second prediction block for the current block of video data using the motion information; form a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and decoding the current block using the multiple hypothesis prediction block.

Clause 123: The clause 122, wherein the instructions causing the processor to form a merge candidate list further cause the processor to: Determine that a neighboring block for the second prediction block is bi-directionally predicted using the first motion information and the second motion information. to do; and forming at least one one-way prediction merge candidate from a neighboring block, comprising instructions that cause the processor to select only one of the first motion information or the second motion information for the at least one one-way prediction merge candidate, A computer-readable storage medium comprising instructions for forming the at least one one-way predictive merge candidate.

Clause 124: The clause 123, wherein the instructions causing the processor to form a merge candidate list further cause the processor to: form a first one-way predictive merge candidate using first motion information; and instructions for forming a second one-way predictive merge candidate using the second motion information.

Clause 125: The method of any of clauses 122-124, further comprising: causing the processor to: code the motion information of the third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, wherein the processor encodes the motion information of the third prediction block using Advanced Motion Vector Prediction (AMVP) mode. The instructions for coding the motion information include instructions for causing the processor to code a motion vector difference (MVD) value with half luma sample resolution, wherein the third prediction block is the basic inter prediction of the neighboring block with respect to the current block. code motion information of the third prediction block, which is a block; and further include instructions for causing the processor to code a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block, wherein the instructions for causing the processor to generate the second prediction block are to cause the processor to perform 6-tap interpolation. A computer-readable storage medium comprising instructions for interpolating half-pixel samples of a reference block to a second prediction block using a filter.

Clause 126: The method of any of clauses 122-125, further comprising: causing the processor to determine whether to apply local lighting compensation (LIC) to a second prediction block depending on whether LIC was applied to the first prediction block. A computer-readable storage medium further comprising instructions.

Clause 127: The computer-readable storage medium of any of clauses 122-126, further comprising instructions to cause the processor to encode the current block prior to decoding the current block.

Depending on the example, certain acts or events of any of the techniques described herein may be performed in different sequences and may be added or merged or removed all together (e.g., implementation of the techniques It should be recognized that not all described acts or events are essential for . Moreover, in certain examples, acts or events may be performed concurrently rather than sequentially, such as through multi-threaded processing, interrupt processing, or multiple processors.

In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media refers to a computer-readable storage medium, such as a tangible medium, such as data storage media, or a computer program that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. It may also include communication media including any medium that allows. In this manner, computer-readable media may generally correspond to (1) non-transitory, tangible computer-readable storage media or (2) communication media, such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure. . A computer program product may include computer-readable media.

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

The instructions may be transferred to one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated circuits. Alternatively, it may be implemented by discrete logic circuitry. Accordingly, the terms “processor” and “processing circuitry” as used herein may refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding or incorporated into a combined codec. Additionally, the techniques may be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or apparatus, including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to highlight functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require implementation by different hardware units. Rather, as described above, the various units may be coupled to a codec hardware unit, or may be provided by a set of interoperable hardware units including one or more processors as described above, together with appropriate software and/or firmware. there is.

Various examples have been described. These and other examples are within the scope of the following claims.

Claims (38)

A method for decoding video data, comprising:
generating a first prediction block for a current block of video data using a basic inter prediction mode;
Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block is merged. coding the merge mode syntax element, indicating whether it is coded using a mode;
Coding motion information for the second prediction block according to the merge mode syntax element, wherein the step of coding motion information for the second prediction block includes the merge mode syntax element for the second prediction block. When indicating that the motion information is coded using a merge mode, forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. coding motion information for a second prediction block;
generating the second prediction block for the current block of the video data using the motion information;
forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and
A method of decoding video data, comprising decoding the current block using the multiple hypothesis prediction block. According to claim 1,
When the merge mode syntax element indicates that a merge mode is used, coding motion information for the second prediction block includes generating a merge index indicating a merge candidate to inherit the motion information for the second prediction block. A method of decoding video data, comprising the step of coding. According to claim 1,
If the merge mode syntax element indicates that merge mode is not used, coding motion information for the second prediction block may include predicting a reference picture list identifier, reference picture index, and motion vector for the second prediction block. A method for decoding video data, comprising coding a character index, and a motion vector difference. According to claim 1,
The steps of forming the merge candidate list are:
determining that a neighboring block for the second prediction block is bi-directionally predicted using first motion information and second motion information; and
Forming at least one unidirectional prediction merge candidate from the neighboring block, wherein forming the at least one unidirectional prediction merge candidate includes the first motion information or the second motion for the at least one unidirectional prediction merge candidate. forming the at least one one-way prediction merge candidate, comprising selecting only one of the information
A method of decoding video data, including. According to claim 4,
The steps of forming the merge candidate list are:
forming a first unidirectional prediction merge candidate using the first motion information; and
Forming a second one-way prediction merge candidate using the second motion information.
A method of decoding video data, including. According to claim 1,
The second prediction block includes one additional prediction hypothesis among a plurality of additional prediction hypotheses, and the method further includes coding motion information for each of the additional prediction hypotheses using the same merge candidate list. , how to decode video data. According to claim 1,
Wherein forming the merge candidate list includes forming the merge candidate list according to a merge candidate list construction process in geometric partitioning mode (GPM). According to claim 1,
The second prediction block includes one additional prediction hypothesis among a plurality of additional prediction hypotheses, and coding motion information for the second prediction block includes:
forming a merge candidate list including two or more merge candidates;
selecting one of the merge candidates from the merge candidate list for the motion information for the second prediction block; and
coding the motion information for the second prediction block using the one of the merge candidates,
The above method is:
forming a reduced merge candidate list by removing the one of the merge candidates from the merge candidate list; and
The method further comprising coding motion information for a third prediction candidate using one of the remaining merge candidates in the reduced merge candidate list. According to claim 8,
Coding a first merge candidate index for the second prediction block, wherein the merge candidate list has N merge candidates, N is a positive integer greater than 1, and the first merge candidate index is a maximum of N. coding the first merge candidate index with possible truncated binary values; and
coding a second merge candidate index for the third prediction candidate, wherein the reduced merge candidate list has N-1 merge candidates, and the second merge candidate index is a maximum possible truncated binary number of N-1. The method of decoding video data further comprising coding the second merge candidate index with a value. According to claim 1,
The merge mode syntax element includes a merge mode syntax element for the basic inter prediction mode of the first prediction block. According to claim 1,
The merge mode syntax element includes a second merge mode syntax element, and the method further includes coding a first merge mode syntax element for the basic inter prediction mode of the first prediction block, wherein the second merge mode syntax element includes A merge mode syntax element is different from the first merge mode syntax element. According to claim 11,
Coding the first merge mode syntax element includes coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and coding the second merge mode syntax element Coding includes coding the second merge mode syntax element using the first CABAC context in response to coding the first merge mode syntax element using the first CABAC context. How to. According to claim 12,
The method of decoding video data, wherein the first CABAC context is a CABAC context used for merge mode. According to claim 12,
The method of decoding video data, wherein the first CABAC context is different from the second CABAC context used for merge mode. According to claim 11,
Coding the first merge mode syntax element includes coding the first merge mode syntax element using a first context adaptive binary arithmetic coding (CABAC) context, and coding the second merge mode syntax element The method of decoding video data, wherein coding includes coding the second merge mode syntax element using a second CABAC context. According to claim 15,
The method of decoding video data, wherein the second CABAC context is different from the first CABAC context. According to claim 1,
Coding the motion information of the third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, wherein coding the motion information of the third prediction block includes a motion vector difference (MVD) with half luma sample resolution. coding motion information of the third prediction block, including coding a value, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block; and
further comprising coding a candidate index identifying the third prediction block as a motion information candidate for the second prediction block,
Wherein generating the second prediction block includes interpolating half-pixel samples of a reference block for the second prediction block using a 6-tap interpolation filter. According to claim 1,
The method further comprising determining whether to apply local illumination compensation (LIC) to the second prediction block depending on whether LIC has been applied to the first prediction block. According to claim 18,
The method of decoding video data, wherein the basic inter prediction mode includes one of unidirectional inter prediction or bidirectional inter prediction. According to claim 18,
further comprising applying LIC to the first prediction block, wherein determining whether to apply LIC to the second prediction block includes applying LIC to the second prediction block in response to applying LIC to the first prediction block. A method of decoding video data, including determining to apply. According to claim 18,
applying LIC to the first prediction block; and
further comprising coding motion information for the second prediction block using advanced motion vector prediction (AMVP) mode,
Determining whether to apply LIC to the second prediction block may include applying LIC to the first prediction block and coding motion information for the second prediction block using AMVP. 2. A method for decoding video data, comprising determining to apply LIC to a prediction block. According to claim 18,
applying LIC to the first prediction block; and
Further comprising coding motion information for the second prediction block using merge mode,
The step of determining whether to apply LIC to the second prediction block is:
coding an LIC flag for a merge candidate of the second prediction block; and
A method for decoding video data, comprising determining whether to apply LIC to the second prediction block according to the value of the LIC flag for the merge candidate of the second prediction block. According to claim 1,
The method of decoding video data further comprising encoding the current block before decoding the current block. A device for decoding video data, comprising:
A memory configured to store video data; and
It includes one or more processors implemented in circuitry, wherein the one or more processors:
generate a first prediction block for a current block of video data using a basic inter prediction mode;
Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block is merge mode code the merge mode syntax element, indicating whether it is coded using;
coding motion information for the second prediction block according to the merge mode syntax element, wherein to code the motion information, the one or more processors are configured to encode the motion information for the second prediction block according to the merge mode syntax element. If the information indicates that it is coded using a merge mode, then coding the motion information is configured to form a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. do;
generate the second prediction block for the current block of the video data using the motion information;
forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and
To decode the current block using the multi-hypothesis prediction block
A device configured to decode video data. According to claim 24,
To form the merge candidate list, the one or more processors:
determine that a neighboring block for the second prediction block is bi-directionally predicted using first motion information and second motion information; and
forming at least one unidirectional prediction merge candidate from the neighboring block, wherein the one or more processors are configured to select only one of the first motion information or the second motion information for the at least one unidirectional prediction merge candidate. , to form the at least one one-way prediction merge candidate.
A device configured to decode video data. According to claim 25,
To form the merge candidate list, the one or more processors:
forming a first one-way prediction merge candidate using the first motion information; and
To form a second one-way prediction merge candidate using the second motion information.
A device configured to decode video data. According to claim 24,
The one or more processors further:
Coding motion information of a third prediction block using an Advanced Motion Vector Prediction (AMVP) mode, wherein, to code the motion information of the third prediction block, the one or more processors perform a motion vector difference with half luma sample resolution. (MVD) value, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block;
to code a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block
and wherein, to generate the second prediction block, the one or more processors are configured to interpolate half-pixel samples of a reference block for the second prediction block using a 6-tap interpolation filter. device. According to claim 24,
The one or more processors are further configured to determine whether to apply local illumination compensation (LIC) to the second prediction block depending on whether LIC was applied to the first prediction block. . According to claim 24,
The device for decoding video data, wherein the one or more processors are further configured to encode the current block before decoding the current block. According to claim 24,
A device for decoding video data, further comprising a display configured to display the decoded video data. According to claim 24,
A device for decoding video data, wherein the device includes one or more of a camera, computer, mobile device, broadcast receiver device, or set top box. A computer-readable storage medium storing instructions, comprising:
The above instructions, when executed, cause the processor to:
generate a first prediction block for a current block of video data using a basic inter prediction mode;
Coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element indicates that motion information for the second prediction block is merged. code the merge mode syntax element, indicating whether to code using a mode;
By coding the motion information for the second prediction block according to the merge mode syntax element, coding the motion information for the second prediction block includes the merge mode syntax element When indicating that the motion information is coded using a merge mode, forming a merge candidate list comprising one or more merge candidates, each of the merge candidates representing respective sets of one-way prediction motion information. code motion information for a prediction block;
use the motion information to generate the second prediction block for the current block of video data;
form a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and
and decoding the current block using the multiple hypothesis prediction block. According to claim 32,
Instructions that cause the processor to form the merge candidate list cause the processor to:
determine that a neighboring block for the second prediction block is bi-directionally predicted using first motion information and second motion information; and
Instructions for forming at least one unidirectional prediction merge candidate from the neighboring block, wherein the processor selects only one of the first motion information or the second motion information for the at least one unidirectional prediction merge candidate. to form the at least one one-way prediction merge candidate, comprising:
A computer-readable storage medium containing instructions. According to claim 33,
Instructions that cause the processor to form the merge candidate list cause the processor to:
Use the first motion information to form a first one-way prediction merge candidate; and
forming a second one-way prediction merge candidate using the second motion information.
A computer-readable storage medium containing instructions. According to claim 32,
causing the processor to:
Coding motion information of a third prediction block using Advanced Motion Vector Prediction (AMVP) mode, wherein instructions causing the processor to code motion information of the third prediction block include: Instructions for coding a motion vector difference (MVD) value with a resolution, wherein the third prediction block is a basic inter prediction block of a neighboring block for the current block. do; and
coding a candidate index that identifies the third prediction block as a motion information candidate for the second prediction block
Contains more commands,
The instructions causing the processor to generate the second prediction block include instructions causing the processor to interpolate half-pixel samples of a reference block for the second prediction block using a 6-tap interpolation filter. Readable storage medium. According to claim 32,
The computer-readable storage medium further comprising instructions that cause the processor to determine whether to apply local illumination compensation (LIC) to the second prediction block depending on whether LIC was applied to the first prediction block. According to claim 32,
instructions that cause the processor to encode the current block before decoding the current block. A device for decoding video data, comprising:
means for generating a first prediction block for a current block of video data using a basic inter prediction mode;
Means for coding a merge mode syntax element for a second prediction block, wherein the second prediction block represents an additional prediction hypothesis for the current block, and the merge mode syntax element includes motion information for the second prediction block. means for coding the merge mode syntax element, indicating whether it is coded using merge mode;
Means for coding motion information for the second prediction block according to the merge mode syntax element, wherein the merge mode syntax element is used to encode motion information for the second prediction block. When indicating that the motion information for means for coding motion information for the second prediction block, indicating:
means for generating the second prediction block for the current block of video data using the motion information;
means for forming a multi-hypothesis prediction block for the current block as a combination of the first prediction block and the second prediction block; and
A device for decoding video data, comprising means for decoding the current block using the multiple hypothesis prediction block.