Motion Vector Differential Code Prediction for Video Coding

Abstract

The video decoder may be configured to construct motion vector candidates using possible code values ​​including positive and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for the block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component.

Description

[Technical field]

[0001]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 249,421, filed September 28, 2021, and U.S. Provisional Patent Application No. 17 / 929,122, filed September 01, 2022, both of which are incorporated by reference in their entireties. U.S. Provisional Patent Application No. 17 / 929,122 claims the benefit of U.S. Provisional Patent Application No. 63 / 249,421, filed September 28, 2021.

[0002]

[0002] This disclosure relates to video encoding and decoding. [Background technology]

[0003] Digital video capabilities may be incorporated into a wide range of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite radio telephones, so-called "smartphones," video teleconferencing devices, video streaming devices, etc. Digital video devices implement video coding techniques such as those described in standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4, Part 10, Advanced Video Coding (AVC), ITU-T H.265 / High Efficiency Video Coding (HEVC), ITU-T H.266 / Generic Video Coding (VVC), and extensions to such standards, as well as proprietary video codecs / formats such as AOMedia Video1 (AV1) developed by the Alliance for Open Media. By implementing such video coding techniques, video devices may more efficiently transmit, receive, encode, decode, and / or store digital video information.

[0004]

[0004] Video coding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove 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) may be partitioned into video blocks, which may also be referred to as coding tree units (CTUs), coding units (CUs), and / or coding nodes. Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction with respect to reference samples in neighboring blocks in the same picture or temporal prediction with respect to reference samples in other reference pictures. A picture may be referred to as a frame, and a reference picture may be referred to as a reference frame. Summary of the Invention

[0005]

[0005] In general, this disclosure describes techniques for inter prediction and inter related information coding. More specifically, it describes devices and techniques for predicting the sign of MVD (motion vector difference). MVD is the difference between a motion vector determined for a particular coding mode and a motion vector predicted using a particular motion vector prediction method. MVD can be represented by the difference between the determined motion vector and the predicted motion vector in both X and Y directions (e.g., called motion vector difference coordinate).

[0006]

[0006] The MVD may include both the absolute value (e.g., magnitude) of the difference as well as the polarity or sign (e.g., positive or negative) of the difference. Signaling information indicating the sign of the MVD coordinate may consume a large amount of bandwidth in overhead signaling. This disclosure describes techniques for predicting the sign of the MVD coordinate for one or more coding modes that use the MVD. For example, the techniques of this disclosure may be used for MVD generated in merge mode with MVD (MMVD) coding mode, affine MMVD, geometric partitioning mode (GPM) with MMVD, multi-hypothesis prediction (MHP) mode, or other coding modes in which it may be beneficial to predict the sign of the MVD or other motion vectors. The techniques of this disclosure may improve the coding efficiency of such coding modes.

[0007]

[0007] In one embodiment, the present disclosure describes a method for decoding video data, the method including constructing motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of motion vector difference components, and a motion vector predictor for a block of video data, sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determining a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decoding the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component.

[0008]

[0008] In another embodiment, the disclosure describes an apparatus configured to decode video data, the apparatus comprising a memory configured to store a block of video data and one or more processors in communication with the memory, the one or more processors configured to construct motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for the block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component.

[0009]

[0009] In another embodiment, the present disclosure describes an apparatus configured to decode video data, the apparatus comprising: means for constructing motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for a block of video data; means for sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; means for determining a respective motion vector difference sign of each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list; and means for decoding the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign of each motion vector difference component.

[0010]

[0010] In another embodiment, the disclosure describes a non-transitory computer-readable storage medium storing instructions that, when executed, cause one or more processors configured to decode video data to construct motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for a block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component.

[0011]

[0011] The 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. [Brief description of the drawings]

[0012] [Figure 1]

[0012] FIG. 1 is a block diagram illustrating an example video encoding and decoding system in which techniques of this disclosure may be implemented. [Diagram 2]

[0013] FIG. 2 is a conceptual diagram illustrating an exemplary simplified affine motion model. [Diagram 3]

[0014] FIG. 1 is a conceptual diagram illustrating example merge mode by motion vector difference (MMVD) search points. [Figure 4]

[0015] FIG. 1 is a conceptual diagram illustrating an example of a geometric partition mode (GPM) division grouped by the same angle. [Diagram 5]

[0016] 4 illustrates example frequency responses of two interpolation filters. [Figure 6]

[0017] FIG. 13 is a conceptual diagram illustrating an example of template matching performed on a search area around an initial motion vector. [Figure 7]

[0018] FIG. 1 is a conceptual diagram illustrating an example of motion vector code prediction for translational inter blocks using template matching. [Figure 8]

[0019] 1 is a block diagram illustrating an example video encoder capable of implementing the techniques of this disclosure. [Figure 9]

[0020] 1 is a block diagram illustrating an example video decoder capable of implementing the techniques of this disclosure. [Figure 10]

[0021] 1 is a flowchart illustrating an example method for encoding a current block, in accordance with techniques of this disclosure. [Figure 11]

[0022] 1 is a flowchart illustrating an example method for decoding a current block in accordance with techniques of this disclosure. [Figure 12]

[0023] 10 is a flowchart illustrating another example method for decoding a current block in accordance with techniques of this disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013]

[0024] Various coding modes, such as inter prediction, use motion vectors to determine predictive blocks. In some embodiments, instead of signaling the coordinates of the motion vector, the video encoder can signal MVD (motion vector difference). MVD is the difference between the motion vector determined for a particular coding mode and the motion vector predicted using a particular motion vector prediction method. MVD can be represented by the difference between the determined motion vector and the predicted motion vector in both the X and Y directions (e.g., called the motion vector difference coordinate).

[0014]

[0025] The MVD may include both the absolute value (e.g., magnitude) of the difference as well as the polarity or sign (e.g., positive or negative) of the difference. Signaling information indicating the sign of the MVD coordinates may consume a large amount of bandwidth in overhead signaling. This disclosure describes techniques for predicting the sign of the MVD coordinates for one or more coding modes that use the MVD. For example, the techniques of this disclosure may be used for MVDs generated in merge mode with MVD (MMVD) coding mode, affine MMVD, geometric partition mode with MMVD (GPM), multiple hypothesis prediction (MHP) mode, or other coding modes in which it may be beneficial to predict the sign of the MVD or other motion vectors. The techniques of this disclosure may improve the coding efficiency of such coding modes.

[0015]

[0026] In one embodiment of the present disclosure, a video decoder may be configured to construct motion vector candidates using possible code values ​​including positive and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for a block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component.

[0016]

[0027] 1 is a block diagram illustrating an example video encoding and decoding system 100 that may implement techniques of this disclosure. The techniques of this disclosure are generally directed to coding (encoding and / or decoding) video data. In general, video data includes any data for processing video. Thus, video data may include raw uncoded video, coded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0017]

[0028] 1, in this example, system 100 includes a source device 102 that provides encoded video data to be decoded and displayed by a destination device 116. Specifically, source device 102 provides the video data to destination device 116 via a computer-readable medium 110. Source device 102 and destination device 116 may comprise any of a wide range of devices, including desktop computers, notebook (i.e., laptop) computers, mobile devices, tablet computers, set-top boxes, telephone handsets such as smartphones, televisions, cameras, display devices, digital media players, video gaming consoles, video streaming devices, broadcast receiver devices, and the like. In some cases, source device 102 and destination device 116 may be capable of wireless communication and thus may be referred to as wireless communication devices.

[0018]

[0029] In the example of FIG. 1, source device 102 includes a video source 104, memory 106, video encoder 200, and output interface 108. Destination device 116 includes an input interface 122, a video decoder 300, memory 120, and a display device 118. According to this disclosure, the video encoder 200 of source device 102 and the video decoder 300 of destination device 116 can be configured to apply techniques for motion vector differential code prediction. Thus, 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 configurations. For example, source device 102 may receive video data from an external video source, such as an external camera. Similarly, destination device 116 may interface with an external display device rather than including an integrated display device.

[0019]

[0030] The system 100 as shown in FIG. 1 is merely an example. In general, any digital video encoding and / or decoding device may perform techniques for motion vector differential code prediction. The source device 102 and the destination device 116 are merely examples of coding devices, such that the source device 102 generates coded video data for transmission to the destination device 116. This disclosure refers to devices that perform coding (encoding and / or decoding) of data as "coding" devices. Thus, the video encoder 200 and the video decoder 300 represent examples of coding devices, specifically, video encoders and video decoders, respectively. In some examples, the source device 102 and the destination device 116 may operate substantially symmetrically, such that each of the source device 102 and the destination device 116 includes video encoding and decoding components. Thus, the system 100 may support unidirectional or bidirectional video transmission between the source device 102 and the destination device 116, for example, video streaming, video playback, video broadcasting, or video telephony.

[0020]

[0031] In general, video source 104 represents a source of video data (i.e., raw, unencoded video data) and provides a continuous series of pictures (also called "frames") of the video data to video encoder 200, which encodes the data for the pictures. 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. As a further alternative, video source 104 may generate computer graphics-based data as source video, or a combination of live video, archived video, and computer-generated video. In each case, video encoder 200 encodes the captured video data, pre-captured video data, or computer-generated video data. Video encoder 200 may reorder the pictures from the order in which they are received (sometimes called "display order") to a coding order for coding. Video encoder 200 may generate a bitstream including the encoded video data. The source device 102 may then output the encoded video data via the output interface 108 to a computer-readable medium 110 for receipt and / or retrieval, for example, by an input interface 122 of the destination device 116 .

[0021]

[0032] The memory 106 of the source device 102 and the memory 120 of the destination device 116 represent general purpose memories. In some examples, the memories 106, 120 may store raw video data, e.g., raw video from the video source 104 and raw decoded video data from the video decoder 300. Additionally or alternatively, the memories 106, 120 may store software instructions executable by, e.g., the video encoder 200 and the video decoder 300, respectively. Although the memories 106 and 120 are shown in this example separately from the video encoder 200 and the video decoder 300, it should be understood that the video encoder 200 and the video decoder 300 may also include internal memories for functionally similar or equivalent purposes. Additionally, the memories 106, 120 may store encoded video data, e.g., output from the video encoder 200 and input to the video decoder 300. In some examples, portions of the memories 106, 120 may be allocated as one or more video buffers, for example, for storing raw decoded video data and / or encoded video data.

[0022]

[0033] The computer-readable medium 110 may represent any type of medium or device capable of transferring encoded video data from the source device 102 to the destination device 116. In one example, the computer-readable medium 110 represents a communication medium for enabling the source device 102 to transmit the encoded video data directly to the destination device 116 in real time, for example, via a radio frequency network or a computer-based network. The output interface 108 may modulate a transmission signal including the encoded video data, and the input interface 122 may demodulate a received transmission signal according to a communication standard such as a wireless communication protocol. The communication medium may comprise any wireless or wired communication medium, such as a 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. The communication medium may include routers, switches, base stations, or any other equipment that may be useful for facilitating communication from the source device 102 to the destination device 116.

[0023]

[0034] In some examples, source device 102 may output the encoded data from output interface 108 to storage device 112. Similarly, destination device 116 may access the encoded data from storage device 112 via input interface 122. Storage device 112 may include any of a variety of distributed or locally accessed data storage media, such as a hard drive, a Blu-ray® disc, a DVD, a CD-ROM, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data.

[0024]

[0035] In some examples, source device 102 may output the encoded video data to a file server 114 or another intermediate storage device, which may store the encoded video data generated by source device 102. Destination device 116 may access the stored video data from file server 114 via streaming or download.

[0025]

[0036] The file server 114 may be any type of server device capable of storing encoded video data and transmitting the encoded video data to the destination device 116. The file server 114 may represent a web server (e.g., for a website), a server configured to provide file transfer protocol services (such as File Transfer Protocol (FTP) or File Delivery over Unidirectional Transport (FLUTE) protocol), a content delivery 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. The 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.

[0026]

[0037] Destination device 116 may access the encoded video data from file server 114 through any standard data connection, including an Internet connection. This may include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., a digital subscriber line (DSL), a cable modem, etc.), or a combination of both suitable for accessing the encoded video data stored on file server 114. Input interface 122 may be configured to operate according to 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.

[0027]

[0038] Output interface 108 and input interface 122 may represent wireless transmitters / receivers, modems, wired networking components (e.g., Ethernet cards), wireless communication components operating according to any of the various IEEE 802.11 standards, or other physical components. In examples in which output interface 108 and input interface 122 comprise wireless components, output interface 108 and input interface 122 may be configured to transfer data, such as encoded video data, according to cellular communication standards such as 4G, 4G-LTE (Long Term Evolution), LTE Advanced, 5G, etc. In some examples in which output interface 108 comprises a wireless transmitter, output interface 108 and input interface 122 may be configured to transfer data, such as encoded video data, according to other wireless standards such as the IEEE 802.11 specification, the IEEE 802.15 specification (e.g., ZigBee™), the Bluetooth standard, etc. In some examples, source device 102 and / or destination device 116 may include respective system-on-chip (SoC) devices. For example, source device 102 may include an SoC device for performing functions attributed to video encoder 200 and / or output interface 108, and destination device 116 may include an SoC device for performing functions attributed to video decoder 300 and / or input interface 122.

[0028]

[0039] The techniques of this disclosure may be applied to video coding to support any of a variety of multimedia applications, such as over-the-air television broadcast, cable television transmission, satellite television transmission, Internet streaming video transmission such as Dynamic Adaptive Streaming over HTTP (DASH), digital video being encoded on a data storage medium, decoding of digital video stored on a data storage medium, or other applications.

[0029]

[0040] An input interface 122 of the destination device 116 receives an encoded video bitstream from a computer-readable medium 110 (e.g., a communication medium, a storage device 112, a file server 114, etc.). The encoded video bitstream may include signaling information defined by the video encoder 200 that is also used by the video decoder 300, such as syntax elements having values ​​that describe characteristics and / or processing of video blocks or other coded units (e.g., slices, pictures, groups of pictures, sequences, etc.). The display device 118 displays decoded pictures of the decoded video data to a user. The display device 118 may represent any of a variety of display devices, such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.

[0030]

[0041] Although not shown in FIG. 1, in some examples, the video encoder 200 and the video decoder 300 may each be integrated with an audio encoder and / or audio decoder and may include appropriate MUX-DEMUX units or other hardware and / or software to handle multiplexed streams that include both audio and video in a common data stream.

[0031]

[0042] The video encoder 200 and the video decoder 300 may each be implemented as any of a variety of suitable encoder and / or decoder circuits, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, software, hardware, firmware, or any combination thereof. When the techniques are implemented partially in software, a device may store instructions for the software on a suitable non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Each of the video encoder 200 and the 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) within the respective device. The device including the video encoder 200 and / or the video decoder 300 may comprise an integrated circuit, a microprocessor, and / or a wireless communication device such as a cellular phone.

[0032]

[0043] The video encoder 200 and the video decoder 300 may operate according to a video coding standard, such as ITU-T H.265, also referred to as High Efficiency Video Coding (HEVC), or extensions thereof, such as multiview and / or scalable video coding extensions. Alternatively, the video encoder 200 and the 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, the video encoder 200 and the video decoder 300 may operate according to a proprietary video codec / format, such as AOMedia Video1 (AV1), an extension of AV1, and / or a successor version of AV1 (e.g., AV2). In other examples, the video encoder 200 and the 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 in conjunction with any video coding technique that uses motion vector differential code prediction.

[0033]

[0044] In general, the video encoder 200 and the video decoder 300 may perform block-based coding of pictures. The term "block" generally refers to a structure that includes data to be processed (e.g., 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, the video encoder 200 and the video decoder 300 may code video data represented in a YUV (e.g., Y, Cb, Cr) format. That is, rather than coding red, green, and blue (RGB) data for samples of a picture, the video encoder 200 and the video decoder 300 may code a luma component and a chroma component, which may include both red and blue chroma components. In some examples, the video encoder 200 converts received RGB formatted data to a YUV representation before encoding, and the video decoder 300 converts the YUV representation to an RGB format. Alternatively, pre-processing and post-processing units (not shown) may perform these conversions.

[0034]

[0045] This disclosure may generally refer to coding (e.g., encoding and decoding) a picture as including a process of encoding or decoding data for a picture. Similarly, this disclosure may refer to coding a block of a picture as including a process of encoding or decoding data for the block, such as predictive and / or residual coding. A coded video bitstream generally includes a set of values ​​for syntax elements that represent coding decisions (e.g., coding modes) and partitioning of a picture into blocks. Thus, references to coding a picture or a block should generally be understood as coding values ​​for the syntax elements that form the picture or block.

[0035]

[0046] 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 coding tree units (CTUs) into CUs according to a quadtree structure. That is, the video coder partitions CTUs and CUs into four equal non-overlapping squares, and each node of the quadtree has either zero or four child nodes. A node with no child nodes may be called a "leaf node", and a CU of such a leaf node 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, a residual quadtree (RQT) represents a partition of TUs. In HEVC, a PU represents inter-predicted data, and a TU represents residual data. An intra-predicted CU includes intra-prediction information, such as an intra-mode indication.

[0036]

[0047] As another example, the video encoder 200 and the video decoder 300 may be configured to operate according to VVC. According to VVC, a video coder (such as the video encoder 200) partitions a picture into multiple coding tree units (CTUs). The video encoder 200 may partition the CTUs according to a tree structure, such as a quad-tree binary tree (QTBT) structure or a multi-type tree (MTT) structure. The QTBT structure eliminates the concept of multiple partition types, such as the separation between CUs, PUs, and TUs in HEVC. The QTBT structure includes two levels, a first level partitioned according to a quad-tree partition, and a second level partitioned according to a binary tree partition. The root node of the QTBT structure corresponds to a CTU. The leaf nodes of the binary tree correspond to coding units (CUs).

[0037]

[0048] In the MTT partitioning structure, blocks may be partitioned using quad tree (QT) partitioning, binary tree (BT) partitioning, and one or more types of triple tree (TT) (also called ternary tree (TT)) partitioning. A triple tree partitioning or ternary tree partitioning is a partitioning in which a block is divided into three sub-blocks. In some examples, a triple tree partitioning or ternary tree partitioning divides a block into three sub-blocks without splitting the original block through the center. The partition types in MTT (e.g., QT, BT, and TT) may be symmetric or asymmetric.

[0038]

[0049] When operating according to the AV1 codec, the video encoder 200 and the video decoder 300 may be configured to code the video data in blocks. In AV1, the largest coding block that may be processed is called a superblock. In AV1, a superblock may be either 128×128 luma samples or 64×64 luma samples. However, in successor video coding formats (e.g., AV2), a superblock may be defined by a different (e.g., larger) luma sample size. In some examples, a superblock is the top level of a block quadtree. The video encoder 200 may further partition the superblock into smaller coding blocks. The video encoder 200 may partition the superblock and other coding blocks into smaller blocks using square or non-square partitions. The non-rectangular blocks may include N / 2×N, N×N / 2, N / 4×N, and N×N / 4 blocks. The video encoder 200 and the video decoder 300 may perform a separate prediction and transformation process for each of the coding blocks.

[0039]

[0050] AV1 also defines tiles of video data. A tile is a rectangular array of superblocks that may be coded independently of other tiles. That is, video encoder 200 and video decoder 300 may encode and decode coding blocks within a tile, respectively, without using video data from other tiles. However, video encoder 200 and video decoder 300 may perform filtering across tile boundaries. Tiles may be uniform or non-uniform in size. Tile-based coding may enable parallel processing and / or multi-threading for encoder and decoder implementations.

[0040]

[0051] In some examples, the video encoder 200 and the video decoder 300 may use a single QTBT or MTT structure to represent each of the luma and chroma components, while in other examples, the video encoder 200 and the video decoder 300 may use two or more QTBT or MTT structures, such as one QTBT / MTT structure for the luma component and another QTBT / MTT structure for both chroma components (or two QTBT / MTT structures for each chroma component).

[0041]

[0052] Video encoder 200 and video decoder 300 may be configured to use quadtree partitioning, QTBT partitioning, MTT partitioning, superblock partitioning, or other partitioning structures.

[0042]

[0053] In some examples, the CTU includes a coding tree block (CTB) of luma samples, two corresponding CTBs of chroma samples for a picture having three sample arrays, or a CTB of samples for a picture coded using three separate color planes and syntax structures used to code a monochrome picture or sample. The CTB may be an N×N block of samples for some value of N such that the division of the components into the CTB is partitioned. A component is an array or a single sample from one of the three arrays (luma and two chromas) that make up a picture in 4:2:0, 4:2:2, or 4:4:4 color format, or a single sample of an array or arrays that make up a picture in monochrome format. In some examples, the coding block is an M×N block of samples for some value of M and N such that the division of the CTB into the coding block is partitioned.

[0043]

[0054] Blocks (e.g., CTUs or CUs) may be grouped in various ways within a picture. As an example, a brick may refer to a rectangular region of a CTU row within a particular tile within a picture. A tile may be a rectangular region of CTUs within a particular tile column and a particular tile row within a picture. A tile column refers to a rectangular region of CTUs with a height equal to the height of the picture and a width specified by a syntax element (e.g., in a picture parameter set). A tile row refers to a rectangular region of CTUs with a height specified by a syntax element (e.g., in a picture parameter set) and a width equal to the width of the picture.

[0044]

[0055] In some examples, a tile may be partitioned into multiple bricks, each of which may include 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, a brick that is a true subset of a tile may not be referred to as a tile. Bricks in a picture may also be arranged as slices. A slice may be an integer number of bricks of a picture that may be contained exclusively within a single Network Abstraction Layer (NAL) Unit. In some examples, a slice includes either several complete tiles or only a series of contiguous complete bricks of a tile.

[0045]

[0056] This disclosure may use "NxN" and "N by N" interchangeably to refer to the sample dimensions of a block (such as a CU or other video block) in terms of the vertical and horizontal dimensions, e.g., 16x16 samples or 16 by 16 samples. In general, a 16x16 CU has 16 samples in the vertical direction (y=16) and 16 samples in the horizontal direction (x=16). Similarly, an NxN CU generally 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 in rows and columns. Moreover, a CU does not necessarily have to have the same number of samples in the horizontal direction as in the vertical direction. For example, a CU may comprise NxM samples, where M is not necessarily equal to N.

[0046]

[0057] Video encoder 200 encodes video data for a CU that represents prediction and / or residual information, as well as other information. The prediction information indicates how the CU will be predicted to form a predictive block for the CU. The residual information generally represents sample-by-sample differences between samples of the CU and samples of the predictive block before encoding.

[0047]

[0058] To predict a CU, the video encoder 200 may generally form a predictive block for the CU through inter prediction or intra prediction. Inter prediction generally refers to predicting a CU from data of a previously coded picture, and intra prediction generally refers to predicting a CU from previously coded data of the same picture. To implement inter prediction, the video encoder 200 may generate a predictive block using one or more motion vectors. The video encoder 200 may generally perform a motion search to identify a reference block that closely matches the CU with respect to the difference between the CU and the reference block, for example. The video encoder 200 may calculate a difference metric using a sum of absolute differences (SAD), a sum of squared differences (SSD), a mean absolute difference (MAD), a mean squared difference (MSD), or other such difference calculation to determine whether the reference block matches well with the current CU. In some examples, the video encoder 200 may predict the current CU using unidirectional prediction or bidirectional prediction.

[0048]

[0059] 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 that represent non-translational motion, such as zooming in or out, rotation, viewpoint shifting, or other irregular motion types.

[0049]

[0060] To perform intra prediction, the video encoder 200 may select an intra prediction mode to generate a prediction block. Some examples of VVC provide 67 intra prediction modes, including various orientation modes, as well as a planar mode and a DC mode. In general, the video encoder 200 selects an intra prediction mode that describes neighboring samples for a current block (e.g., a block of a CU) from which samples of the current block should be predicted. Such samples may generally be above, above and to the left, or to the left of the current block, in the same picture as the current block, assuming that the video encoder 200 codes CTUs and CUs in raster scan order (left to right, top to bottom).

[0050]

[0061] The video encoder 200 encodes data representing a prediction mode for the current block. For example, in the case of an inter prediction mode, the video encoder 200 may encode data representing which of various available inter prediction modes is used as well as motion information for the corresponding mode. In the case of unidirectional or bidirectional inter prediction, for example, the video encoder 200 may encode a motion vector using an advanced motion vector prediction (AMVP) mode or a merge mode. The video encoder 200 may use a similar mode to encode a motion vector for an affine motion compensation mode.

[0051]

[0062] AV1 includes two general techniques for encoding and decoding coding blocks of video data. The two general techniques are intra prediction (e.g., intra-frame prediction or spatial prediction) and inter prediction (e.g., inter-frame prediction or temporal prediction). In the context of AV1, when predicting a block of a current frame of video data using an intra-prediction mode, the video encoder 200 and the video decoder 300 do not use video data from other frames of the video data. In most intra-prediction modes, the video encoder 200 encodes a block of the current frame based on a difference between a sample value in the current block and a predicted value generated from a reference sample in the same frame. The video encoder 200 determines the predicted value generated from the reference sample based on the intra-prediction mode.

[0052]

[0063] Following prediction, such as intra- or inter-prediction, of a block, the video encoder 200 may compute residual data for the block. The residual data, such as a residual block, represents sample-by-sample differences between the block and a predictive 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 transform data in a transform domain rather than the sample domain. For example, the 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. In addition, the video encoder 200 may apply a secondary transform, such as a mode-dependent non-separable secondary transform (MDNSST), a signal-dependent transform, a Karhunen-Loeve transform (KLT), etc., following the initial transform. The video encoder 200 generates transform coefficients following application of the one or more transforms.

[0053]

[0064] As mentioned above, following any transformation to generate transform coefficients, the video encoder 200 may perform quantization of the transform coefficients. Quantization generally refers to a process in which transform coefficients are quantized to possibly reduce the amount of data used to represent the transform coefficients, providing further compression. By performing a quantization process, the video encoder 200 may reduce the bit depth associated with some or all of the transform coefficients. For example, the video encoder 200 may truncate an n-bit value to an m-bit value during quantization, where n is greater than m. In some examples, to perform quantization, the video encoder 200 may perform a bitwise right shift of the value to be quantized.

[0054]

[0065] Following quantization, the video encoder 200 may scan the transform coefficients to generate a one-dimensional vector from the two-dimensional matrix including the quantized transform coefficients. The scan may be designed to place transform coefficients with higher energy (and therefore lower frequency) at the front of the vector and transform coefficients with lower energy (and therefore higher frequency) at the rear of the vector. In some examples, the video encoder 200 may use a predefined scan order for scanning the quantized transform coefficients to generate a serialized vector and then entropy code the quantized transform coefficients of the vector. In other examples, the video encoder 200 may perform an adaptive scan. After scanning the quantized transform coefficients to form the one-dimensional vector, the video encoder 200 may entropy code the one-dimensional vector, for example, according to context-adaptive binary arithmetic coding (CABAC). The video encoder 200 may also entropy code values ​​for syntax elements that describe metadata associated with the encoded video data for use by the video decoder 300 in decoding the video data.

[0055]

[0066] To perform CABAC, the video encoder 200 may assign a context in a context model to a symbol to be transmitted. The context may relate, for example, to whether neighboring values ​​of the symbol are zeroed out or not. The probability decision may be based on the context assigned to the symbol.

[0056]

[0067] Video encoder 200 may further generate syntax data, such as block-based syntax data, picture-based syntax data, and sequence-based syntax data, for example in a picture header, block header, slice header, or other syntax data, such as a sequence parameter set (SPS), a picture parameter set (PPS), or a video parameter set (VPS), to video decoder 300. Video decoder 300 may similarly decode such syntax data to determine how to decode the corresponding video data.

[0057]

[0068] In this manner, video encoder 200 may generate a bitstream including encoded video data, e.g., syntax elements that describe partitions of a picture into blocks (e.g., CUs) and prediction and / or residual information for the blocks. Finally, video decoder 300 may receive the bitstream and may decode the encoded video data.

[0058]

[0069] In general, video decoder 300 performs a reciprocal process to that performed by video encoder 200 to decode encoded video data of a bitstream. For example, video decoder 300 may decode values ​​for syntax elements of a bitstream using CABAC in a manner substantially similar to, but reciprocal to, the CABAC encoding process of video encoder 200. The syntax elements may specify partition information for the partition of a picture into CTUs and the partition of each CTU according to a corresponding partition structure, such as a QTBT structure, to specify CUs of the CTUs. The syntax elements may further specify prediction and residual information for blocks (e.g., CUs) of video data.

[0059]

[0070] The residual information may be represented, for example, by quantized transform coefficients. The video decoder 300 may dequantize and inverse transform the quantized transform coefficients of the block to reconstruct a residual block for the block. The video decoder 300 may use the signaled prediction mode (intra-prediction or inter-prediction) and associated prediction information (e.g., motion information for inter-prediction) to form a predictive block for the block. The video decoder 300 may then combine (sample by sample) the predictive block and the residual block to reconstruct the original block. The video decoder 300 may perform additional processing, such as performing a deblocking process to reduce visual artifacts along block boundaries.

[0060] This disclosure may generally refer to "signaling" some information, such as a syntax element. The term "signaling" may generally refer to communication of values ​​for syntax elements and / or other data used to decode the encoded video data. That is, video encoder 200 may signal values ​​for syntax elements in a bitstream. In general, signaling refers to generating values ​​in a bitstream. As noted above, source device 102 may transfer the bitstream to destination device 116 in substantially real-time or non-real-time, which may occur, such as when storing syntax elements in storage device 112 for later retrieval by destination device 116.

[0061]

[0071] The techniques of this disclosure relate to inter prediction and inter related information coding. More specifically, this disclosure describes a method and device for predicting the sign (e.g., polarity) of MVD (Motion Vector Differential). The techniques of this disclosure may be applied to any extension of existing video codecs, such as High Efficiency Video Coding (HEVC), and / or Versatile Video Coding (VVC), Essential Video Coding (EVC), or may be an efficient coding tool in future video coding standards.

[0062]

[0072] As described in more detail below, in accordance with the techniques of this disclosure, the video decoder 300 may be configured to construct motion vector candidates using possible code values, including positive and negative code values, the magnitudes of each of the motion vector difference coordinates, and a motion vector predictor for the block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a motion vector difference code based on the motion vector code predictor index and the sorted list, and decode the block of video data using the magnitude of the motion vector difference coordinate and the motion vector difference code.

[0063]

[0073] The following sections provide an overview of work in HEVC, JEM technology, and VVC that is relevant to the techniques of this disclosure.

[0064]

[0074] MVD Code Coding in VVC

[0075] In VVC and Enhanced Compression Model (ECM) software currently under development, a video encoder (e.g., video encoder 200) can be configured to signal a motion vector differential (MVD) in a bitstream to a video decoder (e.g., video decoder 300). MVD is the difference between a motion vector (MV) used to derive an inter predictor and its motion vector predictor (MVP). MV, MVP, and MVD are vectors and have two components: a horizontal component (x) and a vertical component (y). When MVDx or MVDy are not equal to 0, video encoder 200 can signal the sign of the component (e.g., a syntax element indicating positive or negative polarity). In some embodiments, the sign is signaled using a CABAC bypass mode (e.g., not context coded but coded using a fixed probability model).

[0065]

[0076] Affine Motion Prediction in VVC

[0077] In HEVC, only a translational motion model is used for motion compensated prediction (MCP). In some embodiments, a translational motion model is used for so-called "normal inter prediction". In the real world, there are many types of motions, not just linear translational motions. Other types of motions can include zooming in / out, rotation, perspective motion, and other irregular motions. In VVC, simplified affine transformation motion compensated prediction can be used to improve coding efficiency. FIG. 2 is a conceptual diagram illustrating an exemplary simplified affine motion model. As shown in FIG. 2, the affine motion field of a current block 400 is represented by control point motion vectors 402 (v0) and 404 (v1). In other embodiments, three control point motion vectors may be used to define the motion.

[0066]

[0078] Taking an affine motion model with two control point motion vectors as an example, the motion vector field (MVF) of a block is described by the following equation:

[0067]

number

[0068] In the formula, (v 0x ,v 0y ) is the motion vector of the control point in the upper left corner, and (v 1x ,v 1y ) is the motion vector of the control point in the upper right corner.

[0069]

[0079] Merge Mode with MVD (MMVD)

[0080] In addition to the merge mode in which the implicitly derived motion information is directly used to generate the prediction sample of the current CU, VVC and ECM can also use a merge mode by motion vector difference (MMVD) mode. Video encoder 200 can signal an MMVD flag after sending a normal merge flag to specify whether the MMVD mode is used for the CU.

[0070]

[0081] In MMVD, after a merging candidate is selected, the merging candidate is further refined by the signaled MVD information. The merging candidate includes motion information of neighboring blocks of the currently coded block. The video decoder can be configured to build a list of merging candidates and can select motion information related to the merging candidate indicated by the video encoder (e.g., by a merging index into the candidate list). The motion information can include a motion vector, a reference picture list, and a prediction direction.

[0071]

[0082] The signaled MVD information includes an MMVD candidate flag, an index to specify the magnitude of motion, and an index indicating the direction of motion. In MMVD mode, one of the first two candidates in the merge list is selected to be used as the starting MV. The MMVD candidate flag is signaled to specify which merge candidate is used between the first and second merge candidates.

[0072]

[0083] Figure 3 is a conceptual diagram illustrating exemplary MMVD search points. In Figure 3, location 410 is the location pointed to by the starting motion vector. For each of reference lists L0 and L1, locations 412 and 414 are determined by adding a positive or negative offset, respectively, to the x coordinate of the starting motion vector. Locations 416 and 418 are determined by adding a positive or negative offset, respectively, to the y coordinate of the starting motion vector. The other locations shown in Figure 3 are determined similarly, but using larger offsets.

[0073]

[0084] The distance index (distanceIDX) specifies the information of the magnitude of the movement and indicates a predefined offset from the starting point (e.g., the start MV). As shown in FIG. 3, the offset is added to either the horizontal or vertical component of the start MV. An example of the relationship between the distance index and the predefined offset is specified in Table 1.

[0074]

[0085] [Table 1]

[0075]

[0086] The direction index (direction IDX) represents the direction of the MVD relative to the starting point (e.g., positive or negative sign of magnitude). The direction index can represent one of four directions shown in Table 2 below. Note that the meaning of the MVD code can change according to the information of the starting MV. When the starting MV is a uni-predictive MV or a bi-predictive MV with both lists pointing to the same side of the current picture (e.g., the picture order counts (POC) of the two references are both greater than the POC of the current picture or both less than the POC of the current picture), the code in Table 2 specifies the sign of the MV offset added to the starting MV.

[0076]

[0087] When the start MV is a bi-predictive MV where the two MVs point to different sides of the current picture (e.g., the POC of one reference is larger than that of the current picture and the POC of the other reference is smaller than that of the current picture) and the difference in POC of list 0 is larger than that of list 1, the signs in Table 2 specify the signs of the MV offsets added to the MV components of list 0 of the start MV, and the signs of the MVs of list 1 have opposite values. Otherwise, when the difference in POC of list 1 is larger than that of list 0, the signs in Table 2 specify the signs of the MV offsets added to the MV components of list 1 of the start MV, and the signs of the MVs of list 0 have opposite values.

[0077]

[0088] The MVD is scaled according to the POC difference in each direction. If the POC difference in both lists is the same, no scaling is required. Otherwise, if the POC difference in list 0 is larger than that of list 1, the MVD of list 1 is scaled by defining the POC difference of L0 as variable td and the POC difference of L1 as variable tb. If the POC difference of L1 is larger than L0, the MVD of list 0 is scaled in the same way. If the starting MV is uni-predicted, the MVD is added to the available MV.

[0078]

[0089] [Table 2]

[0079]

[0090] Affine MMVD

[0091] In ECM, MMVD can be further extended to apply affine inter prediction mode. In affine MMVD, as done in normal inter MMVD, four directions are used to determine the MVD code of each component of MVD, and the corresponding MVD code and direction index table are the same as Table 2 above. However, since affine inter prediction uses two or three control point motion vectors to determine the motion model of a single prediction direction, the same MVD is added to all control point motion vectors (CPMV) to reduce complexity. In the case of bi-prediction, if two reference pictures are located both before and after the current picture to be coded, the MVDs used for the two reference lists will be the same. If two reference pictures are located on different sides of the current picture in time, MVDs with opposite values ​​are added to the CPMV from reference list 1.

[0080]

[0092] Geometric Partitioning Mode (GPM) by MMVD

[0093] In VVC, geometric partitioning mode is supported for inter prediction. The geometric partitioning mode is signaled using a CU level flag as one type of merge mode, along with other merge modes including normal merge mode, MMVD mode, combined inter / intra prediction (CIIP) mode, and sub-block merge mode. In total, 64 partitions are supported by GPM for each possible CU size: w×h=2 m ×2 n , where m, n∈{3...6} except for 8×64 and 64×8.

[0081]

[0094] FIG. 4 is a conceptual diagram illustrating an example of GPM partition 430 grouped by the same angle. When GPM is used, a CU is divided into two parts by a geometrically arranged straight line (see FIG. 4). The position of the partition line is mathematically derived from the angle and offset parameters of a particular partition. Each part of the geometric partition within a CU is inter-predicted using its own motion information. In one embodiment, only uni-prediction is allowed for each partition. For example, each partition has one motion vector and one reference index. A uni-prediction motion constraint is applied to ensure that only two motion-compensated predictions are needed per CU, as in the case of traditional bi-prediction.

[0082]

[0095] If a geometric partition mode is used for the current CU, a geometric partition index indicating the partition mode (angle and offset) of the geometric partition and two merge indices (one per partition) are further signaled. The maximum GPM candidate size is explicitly signaled in the SPS, which specifies the syntax binarization for the GPM merge index. After predicting each part of the geometric partition, the sample values ​​along the geometric partition edges are adjusted using a blending process with adaptive weights. This is the prediction signal for the entire CU, and as for other prediction modes, the transformation and quantization process will be applied to the entire CU.

[0083]

[0096] In one embodiment of ECM, GPM is further extended by applying motion vector refinement on top of the existing GPM unidirectional MV. A flag is first signaled to the GPM CU to specify whether this motion vector refinement mode is used. If the motion vector refinement mode is used, video encoder 200 can decide whether to signal MVD for each geometric partition of the GPM CU. After GPM merge candidates are selected, if MVD is signaled for the geometric partition, the motion of the partition is further refined by the signaled MVD information. All other procedures are kept the same as GPM.

[0084]

[0097] MVD is signaled as a distance / direction pair, similar to MMVD. There are 9 candidate distances (1 / 4-pel, 1 / 2-pel, 1-pel, 2-pel, 3-pel, 4-pel, 6-pel, 8-pel, 16-pel) and 8 candidate directions (4 horizontal / vertical and 4 diagonal) involved in GPM with MMVD (GPM-MMVD).

[0085]

[0098] Multiple Hypothesis Prediction (MHP)

[0099] In the multi-hypothesis inter prediction mode (see, for example, M. Winken et al., "CE10: Multi-hypothesis inter prediction (Test 10.1.2)," Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 13th Meeting, Marrakech, MA, 9-18 January 2019, JVET-M0425), one or more additional motion compensated prediction signals are signaled in addition to the conventional bi-predictive signal. The resulting overall prediction signal is obtained by a sample-wise weighted overlap. The bi-predictive signal p bi and the first additional inter prediction signal / hypothesis h3, the resulting prediction signal p3 is obtained as follows: p3=(1-α)p bi+αh3

[0086]

[0100] The weighting factor α is specified by the syntax element add_hyp_weight_idx according to the following mapping:

[0087] [Table 3]

[0088]

[0101] Similar to the techniques above, two or more additional prediction signals can be used, with the resulting overall prediction signal being iteratively accumulated with each additional prediction signal. p n+1 =(1-α n+1 )p n +α n+1 h n+1

[0089]

[0102] The resulting overall prediction signal is the final p n (For example, p with the largest index n n ) In one embodiment, up to two additional prediction signals can be used (eg, n is limited to 2).

[0090]

[0103] The motion parameters of each additional prediction hypothesis can be signaled either explicitly by specifying a reference index, a motion vector predictor index, and a motion vector differential, or implicitly by specifying a merge index. A separate multiple hypothesis merge flag can be used to distinguish between these two signaling modes.

[0091]

[0104] In one embodiment, for inter AMVP mode, MHP is applied only if unequal weights in bi-prediction with CU-level weights (BCW) mode are selected in bi-prediction mode.

[0092]

[0105] A combination of MHP and bi-directional optical flow (BDOF) coding is possible, however, in one embodiment BDOF is only applied to the bi-predictive signal part of the prediction signal (e.g., usually the first two hypotheses).

[0093]

[0106] 12-tap Interpolation Filter

[0107] In this embodiment, the 8-tap interpolation filter used in VVC is replaced with a 12-tap filter. The 12-tap interpolation filter is derived from a sinc function whose frequency response is cut off at the Nyquist frequency and clipped by a cosine window function. Table 3 gives the filter coefficients for all 16 phases. Figure 5 shows a graph 440 comparing the frequency response of the 12-tap interpolation filter (filter response A) with the VVC interpolation filter (filter response B), all half-pixel phase.

[0094]

[0108] [Table 4]

[0095]

[0109] Template Matching Prediction (TMP)

[0110] Template matching (TM) prediction is a special merge mode based on the Frame-Rate Up Conversion (FRUC) technique. In one exemplary TM mode, the motion information of the block is not signaled and is derived in the video decoder 300. TM may be applied to both AMVP mode and normal merge mode. In AMVP mode, MVP candidate selection is determined based on template matching to choose a candidate that minimizes the difference between the current block template and the reference block template. In normal merge mode, a TM mode flag is signaled to indicate the use of TM, and then TM is applied to the merge candidate indicated by the merge index for MV improvement.

[0096]

[0111] Figure 6 is a conceptual diagram illustrating an example of template matching performed on a search area around an initial motion vector. As shown in Figure 6, template matching is used to derive motion information of the current CU 450 by finding the closest match between the top template 452 and the left template 454 (top and / or left neighboring blocks of the current CU 450) in the current picture 460 and a block (same size as the template) in the reference picture 462. Using the AMVP candidate selected based on the initial matching error, the MVP is refined by template matching. Using the merge candidate indicated by the signaled merge index, the merged MV corresponding to L0 and L1 is refined independently by template matching, and then the less accurate candidate is refined again using the better candidate as a priority.

[0097]

[0112] Cost function: When the motion vector points to a fractional sample position, motion compensated interpolation is used. To reduce the complexity, for template matching, instead of 8-tap DCT-IF interpolation, bilinear interpolation can be used to generate the template on the reference picture. The matching cost C of template matching is calculated as follows:

[0098]

number

[0099] where w is a weighting factor empirically set to 4, and MV and MV sindicates the currently tested MV and the initial MV (e.g., MVP candidate in AMVP mode or merged motion in merge mode), respectively. The sum of absolute differences (SAD) is used as the matching cost for template matching. In one embodiment, when TM is used, the motion is refined by using only luma samples. The derived motion is used for both luma and chroma for motion compensated inter prediction. After the MV is determined, the final motion compensation is performed using an 8-tap interpolation filter for luma and a 4-tap interpolation filter for chroma.

[0100]

[0113] Search method: MV refinement is a pattern-based MV search using a criterion of template matching cost and a hierarchical structure. Two search patterns are supported for MV refinement: diamond search and cross search. The hierarchical structure specifies an iterative process for refining the MV, starting at a coarse MVD precision (e.g., 1 / 4 pel) and ending at a fine precision (e.g., 1 / 8 pel). The MV is directly searched at 1 / 4 luma sample MVD precision using the diamond pattern, and then at 1 / 4 luma sample MVD precision using the cross pattern. This is followed by 1 / 8 luma sample MVD refinement using the cross pattern. The search range of MV refinement is set equal to (-8, +8) luma samples around the initial MV. When the current block is coded using bi-prediction, both MVs are refined independently, and then the best one of them (in terms of matching cost) is set as the priority for further refinement of the other MV using the BCW weight value.

[0101]

[0114] MVD Code Prediction

[0115] MVD code prediction can be used to derive a particular cost given a hypothetical MVD, and output the correct MVD code predictor index by comparing the true MVD with the MVD candidate list sorted by cost. In this way, instead of directly signaling the MVD code in an equal probability (EP) coding mode (e.g., bypass mode), the MVD code predictor index representing the correct MVD code (e.g., the code of the x and / or y components of the MVD) is coded using a context model. The conversion from EP coding to context-based coding is one source of gain. Considering one example of deriving the cost based on the current template and the reference template, the decoder-side MVD code is derived by applying the following steps: 1) Generate a list of MVD candidates based on the absolute values ​​of the MVD components (4 candidates if both X and Y components of the MVD are non-zero, 2 candidates if one component is 0). 2) Compute the cost for each MVD candidate using template matching. 3) Rank the MVD candidates by sorting them based on their computed costs. 4) According to the MVD index obtained from the bitstream (e.g., the MVD index into the sorted MVD candidate list (the MVD index is signaled by the video encoder)), determine the MVD and the associated code in the sorted list.

[0102]

[0116] The template matching cost is measured using some metric between the templates of the current CU and their corresponding reference templates. A diagram of the MVD code prediction process using template matching is shown in Figure 7. MVD code prediction can be applied not only to translational blocks but also to affine blocks.

[0103]

[0117] In Figure 7, a motion vector predictor (MVP) 472 of block 470 points to a specific location in a reference picture. Possible MVD candidates include MVD candidates A, B, C, and D. The MVD candidates include the magnitude and sign of the MVD. The four MVD candidates are offset from the location pointed to by MVP 472. For each of the four MVD candidates, a cost is determined using top and left templates 474, 476, 478, and 480.

[0104]

[0118] This disclosure describes a technique in which MVD code prediction applies not only to normal inter and affine inter modes where MVD is explicitly signaled, but also to MMVD and other modes where MVD is determined from a step size indicating the magnitude of the MVD and from a direction index. As described above, the direction index specifies the direction of the MVD, which is equivalent to specifying the code of the non-zero MVD component. This disclosure describes a technique in which the direction index does not need to be coded, but rather the MVD code can be predicted using the MVD code prediction technique described below. With the introduction of new coding tools in ECM, MVD, the code prediction technique of this disclosure can be further extended to some new coding tools such as affine MMVD, GPM MMVD, and MHP, as described below.

[0105]

[0119] MMVD Direction / Sign Prediction for MMVD

[0120] The video decoder 300 can decode an MMVD step index (e.g., indicative of MVD magnitude information), and then the video decoder 300 can perform MMVD directional (e.g., sign) prediction of this disclosure using the already decoded MVD magnitude information. As described above, the video decoder 300 can be configured to determine the MVD magnitude information from the MMVD step index (e.g., distance IDX in Table 1).

[0106]

[0121] Depending on the POC distance between the current picture and the two reference pictures, the video decoder 300 may apply MVD scaling to the MVD magnitude after the MVD magnitude is derived using the step index. Note that although a single MVD magnitude may be derived, the derived MVD magnitude may be applied to each respective component (e.g., x component and y component) of the MVD. Thus, the MVD magnitude information described herein may be referred to as the respective magnitudes of the motion vector differential components.

[0107]

[0122] Deriving the MVD code is equivalent to deriving the direction index of the signaled MMVD direction index. Unlike normal inter and affine inter modes, where it is known whether the x or y MVD component is non-zero, the MMVD direction index in the MMVD mode specifies one zero component and one non-zero component. For example, the x component of the MVD is non-zero and the y component is zero, and vice versa. Thus, which MVD components are non-zero as well as the associated codes remain unknown when performing MMVD directional prediction. Thus, MMVD directional prediction can be applied to both MVD components together, and the MMVD code predictor index not only represents the code information but also determines which components are non-zero components of the MVD.

[0108]

[0123] The video decoder 300 determines the MMVD sign prediction by generating a template and deriving a template matching cost using a MV derived by adding the MVP to all possible MVDs including different signs and non-zero positions. In the MMVD, the MVP can be indicated by a merge index. In the current exemplary MMVD design, a total of four different MVDs can be used, and therefore four different final MVs can be generated in the motion vector candidate list. As an example, from the decoded MMVD step index, the video decoder 300 determines that the magnitude of the MVD is 16. The video decoder constructs motion vector candidates using all possible sign values ​​(e.g., positive or negative for each MVD component as in Table 2 above). In this example, the motion vector candidates are (16, 0), (-16, 0), (0, 16), and (0, -16).

[0109]

[0124] In one embodiment, the size of the template of the current block used in the cost determination is fixed at a given block coordinate. However, the reference template location varies due to the presence of multiple possible final MVs (e.g., a list of motion vector candidates). Each of the MV candidates in the list can be used to derive a corresponding reference template. The video decoder 300 can then use a measure or metric to derive a cost when comparing the current template and the reference template. In one embodiment, the video decoder 300 can calculate the cost as a sum of absolute differences (SAD). Other metrics such as sum of square error (SSE) or any other exponent can also be used.

[0110]

[0125] After the cost for each possible candidate motion vector is derived, the candidate motion vectors are sorted based on the derived template matching cost. The video decoder 300 decodes an MMVD directional predictor index from the encoded video bitstream, which indicates where in the sorted list the true MVD is located. In one embodiment, the MMVD directional predictor index is signaled using a context-coded bin. Thus, the true MVD with the correct sign and non-zero position can be derived to reconstruct the true final MV. The video decoder 300 determines the final MV by adding the magnitude and determined sign of the MVD to the previous determined MVP.

[0111]

[0126] Therefore, in light of the above, in one embodiment of the present disclosure, the video decoder 300 may determine the signs of the components of the MVD for the MMVD mode using the following technique: The video decoder 300 may construct motion vector candidates using the possible sign values ​​and the magnitudes of each of the motion vector difference components and the motion vector predictor for the block of video data. The possible sign values ​​include positive and negative sign values ​​for each of the possible components of the MVD (x and y components), e.g., as shown in Table 2 above.

[0112]

[0127] In one embodiment, the video decoder 300 can decode a merge index indicating a motion vector predictor from the merge candidate list. The video decoder 300 can determine the magnitude of each of the motion vector differential components by decoding the step index (e.g., distance IDX in Table 1) above, which indicates the magnitude of each of the motion vector differential components.

[0113]

[0128] The video decoder 300 may further be configured to sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list. The video decoder 300 may sort the list by either ascending or descending order of cost. As described above, the video decoder 300 may use a SAD metric based on template matching to determine the cost for each of the candidates. The video decoder 300 may then determine a respective motion vector differential code for each motion vector differential coordinate based on the motion vector code predictor index and the sorted list. For example, the video decoder 300 may decode a motion vector code predictor index from the encoded video bitstream. The motion vector code predictor index indicates a particular motion vector candidate in the sorted candidate list. The video decoder 300 may determine a code value for the magnitude of the MVD for use in determining a final motion vector from the code value of the motion vector candidate in the sorted list corresponding to the motion vector code predictor index.

[0114]

[0129] The video decoder 300 can then decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference signs of each motion vector difference component. For example, the video decoder 300 can apply the respective motion vector difference signs of each motion vector difference component to the respective magnitudes of the motion vector difference components to determine a motion vector difference, add the motion vector difference to a motion vector predictor to determine a final motion vector, and decode the block of video data using the final motion vector. In this manner, the signs of the magnitudes of the MVD components can be determined with less signaling overhead, thus increasing coding efficiency.

[0115]

[0130] MMVD Orientation / Sign Prediction for Affine MMVD

[0131] Similar to the MMVD code / direction prediction procedure described above, the MMVD code predictor index for affine MMVD can be derived similarly. However, due to the characteristics of the affine inter prediction mode, there are some differences.

[0116]

[0132] First, the MVD for the different CPMVs remains the same, and therefore the same MVD is added to each of the CPMVs to derive the final CPMV.

[0117]

[0133] Second, CPMV is not directly used to generate the reference template: a motion vector field is generated based on an affine motion model for each of the 4x4 sub-blocks.

[0118]

[0134] Finally, templates for both the current block and the reference block are generated based on the motion vectors of each of the sub-blocks, and the template matching costs are aggregated across each of the sub-blocks for a final template matching cost.

[0119]

[0135] Once the template matching cost is derived, the MMVD directional predictor index is again used in the same way as in MMVD to derive the true MVD.

[0120]

[0136] MMVD sign / direction prediction for GPM MMVD

[0137] MMVD code / direction prediction can also be extended to GPM MMVD. Due to the characteristics of GPM MMVD, some modifications can be implemented compared to the MVD code prediction design used for MMVD described above.

[0121]

[0138] Unlike MMVD and affine MMVD, where one MVD is equal to, opposite to, or a scaled version of the other MVD in the bi-predictive case, there is no correlation between the two MVDs for the two GPM partitions in the GPM MMVD mode. Due to this fact, up to two MMVD code predictor indices may need to be signaled, and the derivation of the MMVD code predictor is done separately for each of the GPM partitions.

[0122]

[0139] Furthermore, the number of possible MVD code combinations is also increased from 4 to 8 by the additional introduction of diagonal and anti-diagonal directions.

[0123]

[0140] MVD code prediction for MHP.

[0141] The final predictor for MHP includes a base and up to two additional hypotheses. For MHP, the base may be any one of the following modes: inter mode, affine mode, merge mode, affine merge mode, inter MMVD mode, and affine MMVD mode. The additional hypotheses may be either unidirectional inter mode or unidirectional merge mode.

[0124]

[0142] Therefore, MVD code prediction is applicable to MHP in both the MHP base and the additional hypothesis. MVD code prediction can be applied to the MHP base if the base is an inter mode, an affine mode, an inter MMVD mode, or an affine MMVD mode. When the additional hypothesis is selected to be an inter prediction mode, MVD code prediction can also be applied. The MVD code predictor index for the MHP base and the hypothesis is generated separately.

[0125]

[0143] Although MVD code prediction can be applied to both the MHP base and the hypotheses, in some embodiments, MVD code prediction is permitted to be used only for the MHP base, while in other embodiments, MVD code prediction is applied only to the additional hypotheses.

[0126]

[0144] MVD code prediction template generation

[0145] In MVD code prediction, the templates can be selected differently. First, the template shape can have different variations. In one embodiment, both the top template and the left template are used, and the templates are L-shaped. In another embodiment, only the top template is used. In a third embodiment, only the left template is used.

[0127]

[0146] Second, the templates can be generated using different interpolation filters. In template matching (TM) merge mode, the templates are generated using a bilinear interpolation filter. For templates in MVD code prediction, the same bilinear filter can be used in template generation. In another embodiment, a 12-tap interpolation filter can be used to generate the templates.

[0128]

[0147] Third, the template size can be selected to be different. Typically, the template size of the inter mode is selected to be 4 rows and 4 columns, and the template size of the affine mode is selected to be 1 row and 1 column. However, the template size can be changed. For example, the template size of the affine mode can be increased to be the same as that of the inter mode. In another embodiment, the template can be subsampled by a given factor to reduce the computational complexity.

[0129]

[0148] MVD code prediction cost derivation

[0149] In addition to the template matching cost, other costs can be used in MVD code prediction. In one embodiment, instead of using a template, the reconstructed block can be generated by adding a reconstructed residual signal, which can be signaled in the form of quantized transform coefficients, to a predictor. The video decoder 300 can then derive a cost between the current reconstructed block and the reference block. In another embodiment, gradient values ​​around the current block boundary can be used to derive the cost in MVD code prediction.

[0130]

[0150] When deriving the cost, different norms can be used: usually the sum of absolute differences (SAD), which is the L1 norm, or the sum of square errors (SSD), which is the L2 norm, but in principle other Ln norms and any other known norms can be used.

[0131]

[0151] For translational inter SMVD (symmetrical MVD) mode, inter MMVD, and affine MMVD mode, bi-prediction can be selected. Moreover, only the MVD for one reference list needs to be signaled, and the MVD for the other list can be derived from the first list. In this case, when deriving the MVD code prediction cost, either the reference blocks / templates from a single list or both reference lists can be used for the MVD code prediction process.

[0132]

[0152] In one embodiment, only reference blocks / templates from reference list 0 are used to derive the cost. In a second embodiment, only reference blocks / templates from reference list 1 are used to derive the cost. In a third embodiment, reference blocks / templates from both reference lists 0 and 1 are used to derive the cost. In another embodiment, one reference list can derive a template matching cost based on the template of the current block and the reference template, and a second part of the cost is derived from a two-way matching cost between reference blocks from reference list 0 and list 1.

[0133]

[0153] MVD Code Prediction Threshold

[0154] MVD code prediction can be conditionally applied to a particular block when a certain threshold is met. To make MVD code prediction stable, it may be beneficial for the block size to be large enough to include an adequate number of samples for cost derivation. Furthermore, the MVD magnitude is preferably large enough to allow all possible final MVs to be sparsely distributed to include different image regions in the cost derivation. Thus, in one embodiment, a block size-based threshold (usually defined by the number of samples in the block) is applied, and only blocks with a block size larger than (or equal to) the threshold can use MVD code prediction. In another embodiment, the MVD magnitude threshold is used to determine whether MVD code prediction can be applied to a block. In another embodiment, a combination of both thresholds can be applied.

[0134]

[0155] Alternatively, a separate context can be applied for the context coded MVD code bins or MMVD directional prediction indexes depending on the magnitude of the MVD, where the magnitude of the MVD is assumed to be known prior to parsing the MVD code bins or MMVD directional prediction indexes.

[0135]

[0156] General Examples The MVD code prediction process can be described as follows. 1. Analyze the magnitude of the MVD components. 2. Analyze the context coded MVD code predictor index. 3. Construct MV candidates by creating combinations between possible signs and absolute MVD values ​​and add them to the MV predictor. 4. Derive an MVD code prediction cost for each derived MV based on some metric and sorting. 5. Select the true MVD code using the corresponding MVD code predictor index. 6. Add the true MVD to the MV predictor for the final MV.

[0136] All the embodiments mentioned in the above sections can be applied to all inter prediction modes where MVD code prediction is applicable. These modes include those detailed in this specification, namely inter MMVD, affine MMVD, GPM MMVD, and MHP. In addition, MVD code prediction can also be applied to translational inter modes, SMVD modes, and affine inter modes.

[0137]

[0157] Thus, in one embodiment of the present disclosure, the video decoder 300 may be configured to decode a magnitude of a motion vector differential coordinate for a block of video data, decode a motion vector code predictor index, construct motion vector candidates using the possible code values ​​and the magnitude of the motion vector differential coordinate, derive a motion vector differential code prediction cost for each of the motion vector candidates, sort the motion vector candidates based on the cost for each of the motion vector candidates to create a sorted list, determine a motion vector differential code based on the motion vector code predictor index and the sorted list, and decode the block of video data using the magnitude of the motion vector differential coordinate and the motion vector differential code.

[0138]

[0158] 8 is a block diagram illustrating an example video encoder 200 capable of implementing the techniques of this disclosure. FIG. 8 is provided for purposes of illustration and should not be considered a limitation of the techniques as broadly illustrated and described in this disclosure. For purposes of illustration, this disclosure describes a video encoder 200 in accordance with VVC (ITU-T H.266 under development) and HEVC (ITU-T H.265) techniques. However, the techniques of this disclosure may be implemented by video encoding devices configured for other video coding standards and video coding formats, such as AV1 and successors of the AV1 video coding format.

[0139]

[0159] In the embodiment of Figure 8, 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, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a filter unit 216, a decoded picture buffer (DPB) 218, and an entropy coding unit 220. Any or all of the video data memory 230, the mode selection unit 202, the residual generation unit 204, the transform processing unit 206, the quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a filter unit 216, a DPB 218, and an entropy coding unit 220 may be implemented in one or more processors or processing circuits. For example, the units of the video encoder 200 may be implemented as one or more circuits or logic elements as part of a hardware circuit, or as part of a processor, an ASIC, or an FPGA. Moreover, video encoder 200 may include additional or alternative processors or processing circuitry for performing these and other functions.

[0140]

[0160] The video data memory 230 may store video data to be encoded by the components of the video encoder 200. The video encoder 200 may receive the video data stored in the video data memory 230 from, for example, the video source 104 (FIG. 1). The DPB 218 may act as a reference picture memory, storing reference video data for use in predicting subsequent video data by the video encoder 200. The video data memory 230 and the DPB 218 may be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The video data memory 230 and the DPB 218 may be provided by the same memory device or separate memory devices. In various examples, the video data memory 230 may be on-chip with other components of the video encoder 200, as shown, or may be off-chip relative to those components.

[0141]

[0161] In this disclosure, references to video data memory 230 should not be construed as limited to memory internal to video encoder 200, unless specifically stated as such, or to memory external to video encoder 200, unless specifically stated as such. 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 a current block to be encoded). Memory 106 of FIG. 1 may also provide temporary storage of outputs from various units of video encoder 200.

[0142]

[0162] The various units in FIG. 8 are shown to aid in understanding the operations performed by the video encoder 200. The units may be implemented as fixed-function circuits, programmable circuits, or a combination thereof. A fixed-function circuit refers to a circuit that provides a specific function, and the operations that may be performed are predefined. A programmable circuit refers to a circuit that may be programmed to perform various tasks, and provides flexible functionality in the operations that may be performed. For example, a programmable circuit may execute software or firmware that causes the programmable circuit to operate in a manner defined by the software or firmware instructions. Although a fixed-function circuit may execute software instructions (e.g., to receive parameters or output parameters), the type of operations that the fixed-function circuit performs is generally invariant. In some examples, one or more of the units may be different circuit blocks (fixed function or programmable), and in some examples, one or more of the units may be an integrated circuit.

[0143]

[0163] The video encoder 200 may include an arithmetic logic unit (ALU), a primitive functional unit (EFU), digital circuits, analog circuits, and / or a programmable core formed from programmable circuits. In examples in which the operations of the video encoder 200 are implemented using software executed by programmable circuits, the memory 106 (FIG. 1) may store instructions for the software (e.g., object code) that the video encoder 200 receives and executes, or another memory (not shown) within the video encoder 200 may store such instructions.

[0144]

[0164] The video data memory 230 is configured to store the received video data. The video encoder 200 may retrieve pictures of the video data from the video data memory 230 and provide the video data to the residual generation unit 204 and the mode selection unit 202. The video data in the video data memory 230 may be raw video data to be encoded.

[0145]

[0165] The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra prediction unit 226. The mode selection unit 202 may include additional functional units for performing video prediction according to other prediction modes. By way of example, the mode selection unit 202 may include a palette unit, an intra block copy unit (which may be part of the motion estimation unit 222 and / or the motion compensation unit 224), an affine unit, a linear model (LM) unit, etc.

[0146]

[0166] The mode selection unit 202 typically coordinates multiple encoding passes to test combinations of encoding parameters and the rate-distortion values ​​obtained for such combinations. The encoding parameters may include partitioning of the CTUs into CUs, prediction modes for the CUs, transform types for residual data of the CUs, quantization parameters for residual data of the CUs, etc. The mode selection unit 202 may ultimately select a combination of encoding parameters that has a better rate-distortion value than the other tested combinations.

[0147]

[0167] Video encoder 200 may partition a picture retrieved from video data memory 230 into a series of CTUs and may encapsulate one or more CTUs within a slice. Mode select unit 202 may partition the CTUs of a picture according to a tree structure, such as the MTT structure, the QTBT structure, the superblock structure, or the quadtree structure described above. As described above, video encoder 200 may form one or more CUs from partitioning the CTUs according to the tree structure. Such CUs may also be generally referred to as "video blocks" or "blocks."

[0148]

[0168] In general, the mode selection unit 202 also controls its components (e.g., the motion estimation unit 222, the motion compensation unit 224, and the intra prediction unit 226) to generate a prediction block for a current block (e.g., a current CU, or in HEVC, an overlapping portion of a PU and a TU). In the case of inter prediction of the current block, the motion estimation unit 222 may perform motion search to identify one or more closely matching reference blocks among one or more reference pictures (e.g., one or more previously coded pictures stored in the DPB 218). Specifically, the motion estimation unit 222 may calculate a value representing how similar a potential reference block is to the current block according to, for example, a sum of absolute differences (SAD), a sum of squared differences (SSD), a mean absolute difference (MAD), a mean squared difference (MSD), etc. The motion estimation unit 222 may generally perform these calculations using a sample-by-sample difference between the current block and the reference block under consideration. Motion estimation unit 222 may identify the reference block having the lowest value resulting from these calculations, which indicates the reference block that best matches the current block.

[0149]

[0169] The motion estimation unit 222 may form one or more motion vectors (MVs) that define the position of a reference block in a reference picture relative to the position of a current block in a current picture. The motion estimation unit 222 may then provide the motion vectors to the motion compensation unit 224. For example, in the case of unidirectional inter prediction, the motion estimation unit 222 may provide a single motion vector, while in the case of bidirectional inter prediction, the motion estimation unit 222 may provide two motion vectors. The motion compensation unit 224 may then generate a predictive block using the motion vectors. For example, the motion compensation unit 224 may use the motion vectors to retrieve data of the reference block. As another example, if the motion vectors have fractional sample precision, the motion compensation unit 224 may interpolate values ​​for the predictive block according to one or more interpolation filters. Moreover, in the case of bidirectional inter prediction, the motion compensation unit 224 may retrieve data for the two reference blocks identified by the respective motion vectors and combine the retrieved data, for example, through a sample-wise average or a weighted average.

[0150]

[0170] When operating according to the AV1 video coding format, the motion estimation unit 222 and the motion compensation unit 224 may be configured to encode coding blocks of video data (e.g., both luma coding blocks and chroma coding blocks) using translational motion compensation, affine motion compensation, overlapped block motion compensation (OBMC), and / or synthetic inter-intra prediction.

[0151]

[0171] As another example, in the case of intra prediction or intra predictive coding, the intra prediction unit 226 may generate a predictive block from samples neighboring the current block. For example, in the case of a directional mode, the intra prediction unit 226 may generally mathematically combine values ​​of neighboring samples to populate these calculated values ​​in a defined direction across the current block to produce the predictive block. As another example, in the case of a DC mode, the intra prediction unit 226 may calculate an average of samples neighboring the current block and generate a predictive block to include this resulting average for each sample of the predictive block.

[0152]

[0172] When operating according to the AV1 video coding format, intra prediction unit 226 may be configured to encode coding blocks of video data (e.g., both luma coding blocks and chroma coding blocks) using directional intra prediction, non-directional intra prediction, recursive filter intra prediction, chroma-from-luma (CFL) prediction, intra block copy (IBC), and / or color palette modes. Mode selection unit 202 may include additional functional units for performing video prediction according to other prediction modes.

[0153]

[0173] The mode select unit 202 provides the prediction block to the residual generation unit 204. The residual generation unit 204 receives a raw, uncoded version of the current block from the video data memory 230 and receives the prediction block from the mode select 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 a residual block for the current block. In some examples, the residual generation unit 204 may also determine differences between sample values ​​in the residual block to generate the residual block using residual differential pulse code modulation (RDPCM). In some examples, the residual generation unit 204 may be formed using one or more subtractor circuits that perform binary subtraction.

[0154]

[0174] In an example where the mode select unit 202 partitions a CU into PUs, each PU may be associated with a luma prediction unit and a corresponding chroma prediction unit. The video encoder 200 and the video decoder 300 may support PUs having various sizes. As indicated above, the size of a CU may refer to the size of the luma coding block of the CU, and the size of a PU may refer to the size of the luma prediction unit of the PU. Assuming that the size of a particular CU is 2N×2N, the video encoder 200 may support a PU size of 2N×2N or N×N for intra prediction, and a symmetric PU size of 2N×2N, 2N×N, N×2N, N×N, or similar for inter prediction. The video encoder 200 and the video decoder 300 may also support asymmetric partitioning for PU sizes of 2N×nU, 2N×nD, nL×2N, and nR×2N for inter prediction.

[0155]

[0175] In examples where the mode select unit 202 does not further partition the CUs into PUs, each CU may be associated with a luma coding block and a corresponding chroma coding block. As above, the size of a CU may refer to the size of the luma coding block of the CU. The video encoder 200 and the video decoder 300 may support CU sizes of 2N×2N, 2N×N, or N×2N.

[0156]

[0176] For other video coding techniques, such as intra block copy mode coding, affine mode coding, and linear model (LM) mode coding, as some examples, the mode select unit 202 generates a predictive block for the current block being coded via a respective unit associated with the coding technique. In some examples, such as palette mode coding, the mode select unit 202 may not generate a predictive block, but instead generate syntax elements that indicate a scheme for reconstructing the block based on a selected palette. In such modes, the mode select unit 202 may provide these syntax elements to the entropy coding unit 220 to be coded.

[0157]

[0177] As described above, the residual generation unit 204 receives the video data for a current block and a corresponding predictive block. The residual generation unit 204 then generates a residual block for the current block. To generate the residual block, the residual generation unit 204 calculates the sample-by-sample difference between the predictive block and the current block.

[0158]

[0178] 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 the 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, e.g., a linear transform and a secondary transform, such as a rotation transform, on the residual block. In some examples, transform processing unit 206 does not apply a transform to the residual block.

[0159]

[0179] When operating according to 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 the transform coefficient block. For example, transform processing unit 206 may apply a horizontal / vertical transform combination that may include a discrete cosine transform (DCT), an asymmetric discrete sine transform (ADST), an inverse ADST (e.g., ADST in reverse order), and an identity transform (IDTX). When using an identity transform, the transform is skipped in one of the vertical or horizontal directions. In some examples, the transform process may be skipped.

[0160]

[0180] The quantization unit 208 may quantize the transform coefficients in the transform coefficient block to generate a quantized transform coefficient block. The 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. The video encoder 200 (e.g., via the mode selection unit 202) may adjust the degree of quantization applied to the transform coefficient block associated with the current block by adjusting the QP value associated with the CU. Quantization may result in loss of information, and thus the quantized transform coefficients may be less accurate than the original transform coefficients generated by the transform processing unit 206.

[0161]

[0181] Inverse quantization unit 210 and inverse transform processing unit 212 may apply inverse quantization and inverse transform, respectively, to the quantized transform coefficient block to reconstruct a residual block from the transform coefficient block. Reconstruction unit 214 may generate a reconstructed block that corresponds to the current block (possibly with some distortion) based on the reconstructed residual block and the predictive block generated by mode selection unit 202. For example, reconstruction unit 214 may add samples of the reconstructed residual block to corresponding samples from the predictive block generated by mode selection unit 202 to generate a reconstructed block.

[0162]

[0182] Filter unit 216 may perform one or more filter operations on the reconstructed block. For example, filter unit 216 may perform a deblocking operation to reduce blockiness artifacts along the edges of a CU. The operations of filter unit 216 may be skipped in some examples.

[0163]

[0183] 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 a deblocking operation to reduce blockiness artifacts along edges of a CU. In other examples, filter unit 216 may apply a constrained directional enhancement filter (CDEF), which may be applied after deblocking and may include application of a non-separable, nonlinear, low-pass directional filter based on the estimated edge direction. Filter unit 216 may also include a loop restoration filter, which may be applied after CDEF and may include a separable symmetric normalized Wiener filter or a dual autoinduction filter.

[0164]

[0184] Video encoder 200 stores the reconstructed blocks in DPB 218. For example, in examples where the operations of filter unit 216 are not performed, reconstruction unit 214 may store the reconstructed blocks in DPB 218. In examples where 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 reference pictures formed from the reconstructed (and potentially filtered) blocks from DPB 218 to inter predict blocks of a later-encoded picture. In addition, intra prediction unit 226 may use reconstructed blocks in DPB 218 of the current picture to intra predict other blocks in the current picture.

[0165]

[0185] In general, the entropy encoding unit 220 may entropy encode syntax elements received from other functional components of the video encoder 200. For example, the entropy encoding unit 220 may entropy encode quantized transform coefficient blocks from the quantization unit 208. As another example, the entropy encoding unit 220 may entropy encode predictive syntax elements (e.g., motion information for inter prediction or intra mode information for intra prediction) from the mode selection unit 202. The entropy encoding unit 220 may perform one or more entropy encoding operations on syntax elements, which are another example of video data, to generate entropy encoded data. For example, entropy encoding unit 220 may perform a context-adaptive variable length coding (CAVLC) operation, a CABAC operation, a variable-length-to-variable-length (V2V) coding operation, a syntax-based context-adaptive binary arithmetic coding (SBAC) operation, a probability interval partitioned entropy (PIPE) coding operation, an exponential-Golomb coding operation, or another type of entropy coding operation on the data. In some examples, entropy encoding unit 220 may operate in a bypass mode in which syntax elements are not entropy coded.

[0166]

[0186] The video encoder 200 may output a bitstream that includes entropy coding syntax elements needed to reconstruct blocks of a slice or picture. In particular, the entropy coding unit 220 may output the bitstream.

[0167]

[0187] According to AV1, the entropy encoding unit 220 may be configured as a symbol-to-symbol adaptive multi-symbol arithmetic coder. A syntax element in AV1 includes an alphabet of N elements, and a context (e.g., a probability model) includes a set of N probabilities. The entropy encoding unit 220 may store the probabilities as n-bit (e.g., 15-bit) cumulative distribution functions (CDFs). The entropy encoding unit 22 may perform recursive scaling with an update factor based on the alphabet size to update the context.

[0168]

[0188] The operations described above are described with respect to blocks. Such descriptions should be understood as being operations for a luma coding block and / or a chroma coding block. As described above, in some examples, the luma coding block and the chroma coding block are the luma component and the chroma component of a CU. In some examples, the luma coding block and the chroma coding block are the luma component and the chroma component of a PU.

[0169]

[0189] In some examples, operations performed with respect to luma coding blocks do not need to be repeated for chroma coding blocks. As one example, operations to identify motion vectors (MVs) and reference pictures for luma coding blocks do not need to be repeated to identify MVs and reference pictures for chroma blocks. Rather, MVs for luma coding blocks may be scaled to determine MVs for chroma blocks, and the reference pictures may be the same. As another example, the intra prediction process may be the same for luma coding blocks and chroma coding blocks.

[0170]

[0190] Video encoder 200 represents one embodiment of a device configured to encode video data, including a memory configured to store the video data and one or more processing units implemented in circuitry and configured to perform one or more techniques of the present disclosure described above for MVD code prediction.

[0171]

[0191] 9 is a block diagram illustrating an example video decoder 300 capable of performing techniques of this disclosure. FIG. 9 is provided for purposes of illustration and is not intended to limit the techniques as broadly illustrated and described in this disclosure. For purposes of illustration, this disclosure describes a video decoder 300 in accordance with VVC (ITU-T H.266 under development) and HEVC (ITU-T H.265) techniques. However, the techniques of this disclosure may be performed by video coding devices configured according to other video coding standards.

[0172]

[0192] In the embodiment of FIG. 9, the 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, an inverse transform processing unit 308, a reconstruction unit 310, a filter unit 312, and a decoded picture buffer (DPB) 314. Any or all of the CPB memory 320, the entropy decoding unit 302, the prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, the filter unit 312, and the DPB 314 may be implemented in one or more processors or processing circuits. For example, the units of the video decoder 300 may be implemented as one or more circuits or logic elements as part of a hardware circuit, or as part of a processor, ASIC, or FPGA. Moreover, the video decoder 300 may include additional or alternative processors or processing circuitry for performing these and other functions.

[0173]

[0193] 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 other prediction modes. By way of example, 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.

[0174]

[0194] When operating according to AV1, the compensation unit 316 may be configured to decode coding blocks of the video data (e.g., both luma coding blocks and chroma coding blocks) using translational motion compensation, affine motion compensation, OBMC, and / or synthetic inter-intra prediction, as described above. The intra prediction unit 318 may be configured to decode coding blocks of the video data (e.g., both luma coding blocks and chroma coding blocks) using directional intra prediction, non-directional intra prediction, recursive filter intra prediction, CFL, intra block copy (IBC), and / or color palette mode, as described above.

[0175]

[0195] The CPB memory 320 may store video data, such as an encoded video bitstream, to be decoded by components of the video decoder 300. The video data stored in the CPB memory 320 may be obtained, for example, from the computer-readable medium 110 (FIG. 1). The CPB memory 320 may include a CPB that stores encoded video data (e.g., syntax elements) from the encoded video bitstream. The CPB memory 320 may also store video data other than syntax elements of coded pictures, such as temporary data representing output from various units of the video decoder 300. The DPB 314 generally stores decoded pictures that the video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures of the encoded video bitstream. The CPB memory 320 and the DPB 314 may be formed by any of a variety of memory devices, such as DRAM, including SDRAM, MRAM, RRAM, or other types of memory devices. The CPB memory 320 and the DPB 314 may be provided by the same memory device or separate memory devices. In various examples, the CPB memory 320 may be on-chip with other components of the video decoder 300, or may be off-chip relative to those components.

[0176]

[0196] Additionally or alternatively, in some examples, video decoder 300 may retrieve coded video data from memory 120 (FIG. 1). That is, memory 120 may store data such as those discussed above for CPB memory 320. Similarly, 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 processing circuitry of video decoder 300.

[0177]

[0197] The various units shown in FIG. 9 are presented to aid in understanding the operations performed by the video decoder 300. The units may be implemented as fixed function circuits, programmable circuits, or a combination thereof. As with FIG. 8, fixed function circuits refer to circuits that provide a particular function and are predefined in the operations that they may perform. Programmable circuits refer to circuits that may be programmed to perform a variety of tasks and provide flexible functionality in the operations that they may perform. For example, a programmable circuit may execute software or firmware that causes the programmable circuit to operate in a manner defined by the software or firmware instructions. Although a fixed function circuit may execute software instructions (e.g., to receive a parameter or output a parameter), the type of operation that the fixed function circuit performs is generally immutable. In some examples, one or more of the units may be different circuit blocks (fixed function or programmable), and in some examples, one or more of the units may be an integrated circuit.

[0178]

[0198] The video decoder 300 may include a programmable core formed from ALUs, EFUs, digital circuits, analog circuits, and / or programmable circuits. In examples in which the operations of the video decoder 300 are performed by software executing on programmable circuits, on-chip or off-chip memory may store instructions (e.g., object code) of the software that the video decoder 300 receives and executes.

[0179]

[0199] The entropy decoding unit 302 may receive the encoded video data from the CPB and entropy decode the video data to recover the syntax elements. The prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, and the filter unit 312 may generate decoded video data based on the syntax elements extracted from the bitstream.

[0180]

[0200] In general, the video decoder 300 reconstructs a picture on a block-by-block basis. The video decoder 300 may perform a reconstruction operation on each block individually (here, the block currently being reconstructed, i.e., decoded, may be referred to as the “current block”).

[0181]

[0201] The entropy decoding unit 302 may entropy decode syntax elements that specify the quantized transform coefficients of the quantized transform coefficient block as well as transform information, such as a quantization parameter (QP) and / or a transform mode indication. The inverse quantization unit 306 may use the QP associated with the quantized transform coefficient block to determine the degree of quantization, and similarly the degree of inverse quantization that the inverse quantization unit 306 should apply. The inverse quantization unit 306 may, for example, perform a bitwise left shift operation to inverse quantize the quantized transform coefficients. The inverse quantization unit 306 may thereby form a transform coefficient block including the transform coefficients.

[0182]

[0202] After the inverse quantization unit 306 forms the transform coefficient block, the 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, the inverse transform processing unit 308 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotational transform, an inverse transform, or another inverse transform to the transform coefficient block.

[0183]

[0203] Further, prediction processing unit 304 generates a prediction block according to the prediction information syntax element entropy decoded by entropy decoding unit 302. For example, if the prediction information syntax element indicates that the current block is inter predicted, motion compensation unit 316 may generate a prediction block. In this case, the prediction information syntax element may indicate a reference picture in DPB 314 from which to retrieve a reference block, as well as a motion vector that specifies the location of the reference block in the reference picture relative to the location of the current block in the current picture. Motion compensation unit 316 may generally perform an inter prediction process in a manner substantially similar to that described with respect to motion compensation unit 224 (FIG. 8).

[0184]

[0204] As another example, if the prediction information syntax element indicates that the current block is intra predicted, the intra prediction unit 318 may generate a prediction block according to the intra prediction mode indicated by the prediction information syntax element. Again, the intra prediction unit 318 may generally perform an intra prediction process in a manner substantially similar to that described with respect to the intra prediction unit 226 (FIG. 8). The intra prediction unit 318 may retrieve data of samples neighboring the current block from the DPB 314.

[0185]

[0205] The reconstruction unit 310 may reconstruct the current block using the predictive block and the residual block. For example, the reconstruction unit 310 may add samples of the residual block to corresponding samples of the predictive block to reconstruct the current block.

[0186]

[0206] Filter unit 312 may perform one or more filter operations on the reconstructed block. For example, filter unit 312 may perform a deblocking operation to reduce blockiness artifacts along edges of the reconstructed block. In all examples, the operations of filter unit 312 may not necessarily be performed.

[0187]

[0207] The video decoder 300 may store the reconstructed blocks in the DPB 314. For example, in examples where the operation of the filter unit 312 is not required, the reconstruction unit 310 may store the reconstructed blocks in the DPB 314. In examples where the operation of the filter unit 312 is performed, the filter unit 312 may store the filtered reconstructed blocks in the DPB 314. As described above, the DPB 314 may provide reference information to the prediction processing unit 304, such as samples of the current picture for intra prediction and previously decoded pictures for subsequent motion compensation. Additionally, the video decoder 300 may output decoded pictures (e.g., decoded video) from the DPB 314 for later presentation on a display device, such as the display device 118 of FIG. 1.

[0188]

[0208] In this manner, the video decoder 300 represents one embodiment of a video decoding device including a memory configured to store video data; and one or more processing units implemented in a circuit and configured to construct motion vector candidates using possible code values ​​including positive and negative code values, the magnitudes of the respective motion vector difference components, and a motion vector predictor for the block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component.

[0189]

[0209] 10 is a flowchart illustrating an example method for encoding a current block, which may comprise a current CU, in accordance with the techniques of this disclosure. Although described with respect to video encoder 200 (FIGS. 1 and 8), it should be understood that other devices may be configured to perform a method similar to that of FIG.

[0190]

[0210] In this example, video encoder 200 may first predict the current block (350). For example, video encoder 200 may form a predictive block for the current block. Video encoder 200 may then calculate a residual block for the current block (352). To calculate the residual block, video encoder 200 may calculate a difference between the original uncoded block and the predictive block for the current block. Video encoder 200 may then transform the residual block and quantize transform coefficients of the residual block (354). Video encoder 200 may then scan the quantized transform coefficients of the residual block (356). During or following the scan, video encoder 200 may entropy code the transform coefficients (358). For example, video encoder 200 may code the transform coefficients using CAVLC or CABAC. Video encoder 200 may then output entropy coded data for the block (360).

[0191]

[0211] 11 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 comprise a current CU. Although described with respect to video decoder 300 (FIGS. 1 and 9), it should be understood that other devices may be configured to perform a method similar to that of FIG.

[0192]

[0212] The video decoder 300 may receive entropy coded data for the current block, such as the entropy coded prediction information and the entropy coded data of the transform coefficients of the residual block corresponding to the current block (370). The video decoder 300 may entropy decode the entropy coded data to determine prediction information for the current block and reconstruct the transform coefficients of the residual block (372). The video decoder 300 may predict the current block, e.g., using an intra prediction mode or an inter prediction mode as indicated by the prediction information for the current block, to calculate a predictive block for the current block (374). The video decoder 300 may then inverse scan the reconstructed transform coefficients to create a block of quantized transform coefficients (376). The video decoder 300 may then inverse quantize the transform coefficients and apply an inverse transform to the transform coefficients to generate a residual block (378). The video decoder 300 may finally decode the current block by combining the predictive block and the residual block (380).

[0193]

[0213] 12 is a flowchart illustrating another example method for decoding a current block according to the techniques of this disclosure. The technique of FIG. 12 may be performed by one or more structural components of the video decoder 300, including the motion compensation unit 316.

[0194]

[0214] In one embodiment of the present disclosure, the video decoder 300 may be configured to construct motion vector candidates using possible code values, including positive and negative code values, the magnitudes of each of the motion vector difference components, and a motion vector predictor for a block of video data (1200). The video decoder 300 may be further configured to sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list (1202). The video decoder 300 may further determine a respective motion vector difference sign for each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list (1204), and may decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign for each motion vector difference component (1206).

[0195]

[0215] In the above embodiments, blocks of video data may be coded using one of InterMerge with Motion Vector Differential (MMVD) mode, Affine MMVD, Geometric Partitioning Mode with MMVD (GPM), or Multiple Hypothesis Prediction (MHP) mode.

[0196]

[0216] In a particular embodiment, the block of video data is coded using an inter MMVD mode. In this embodiment, the video decoder 300 may be further configured to decode a merge index indicative of a motion vector predictor, decode a step index indicative of a magnitude of each of the motion vector difference coordinates, and decode a motion vector sign predictor index. The video decoder 300 may be further configured to apply a respective motion vector difference sign of each motion vector difference component to a respective magnitude of the motion vector difference component to determine a motion vector difference, add the motion vector difference to the motion vector predictor to determine a final motion vector, and decode the block of video data using the final motion vector.

[0197]

[0217] In another particular embodiment, the block of video data is coded using an affine MMVD mode and the motion vector predictor includes two or three control point motion vectors. In this embodiment, the video decoder 300 may be configured to determine the control point motion vectors, decode a step index indicating the magnitude of each of the motion vector difference coordinates, and decode the motion vector sign predictor index. The video decoder 300 may be further configured to apply the motion vector difference sign of each motion vector difference component to the magnitude of each of the motion vector difference components to determine the motion vector difference, add the motion vector difference to each of the control point motion vectors to determine a final control point motion vector, and decode the block of video data using the final control point motion vector.

[0198]

[0218] In any of the above embodiments, the video decoder 300 may be further configured to determine the cost using template matching. As an example, when the block of video data is coded using an affine MMVD merge with motion vector difference (MMVD) mode, the video decoder 300 may be configured to determine the cost using sub-block based template matching. Furthermore, in any of the above embodiments, the video decoder 300 may be further configured to scale the magnitude of each of the motion vector difference components based on a picture order count (POC) difference.

[0199]

[0219] Additional aspects of the disclosure are described below.

[0200]

[0220] Aspect 1A - A method for coding video data, comprising: decoding a magnitude of a motion vector differential coordinate of a block of video data; decoding a motion vector code predictor index; constructing motion vector candidates using possible code values ​​and the magnitude of the motion vector differential coordinate; deriving a motion vector differential code prediction cost for each of the motion vector candidates; sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; determining a motion vector differential code based on the motion vector code predictor index and the sorted list; and decoding the block of video data using the magnitude of the motion vector differential coordinate and the motion vector differential code.

[0201]

[0221] Aspect 2A - The method described in aspect 1A, in which blocks of video data are coded using one of inter-merge with motion vector differential (MMVD) mode, affine MMVD, geometric partition mode with MMVD (GPM), and multiple hypothesis prediction (MHP) mode.

[0202]

[0222] Aspect 3A - A device for coding video data, comprising one or more means for performing the method according to any one of aspects 1A to 2A.

[0203]

[0223] Example 4A - The device of Example 3A, wherein the one or more means include one or more processors implemented in the circuit.

[0204]

[0224] Example 5A - The device of any one of Examples 3A and 4A, further comprising a memory for storing video data.

[0205]

[0225] Example 6A - The device of any one of Examples 3A to 5A, further comprising a display configured to display the decoded video data.

[0206]

[0226] Aspect 7A - The device of any one of aspects 3A to 6A, wherein the device includes one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

[0207]

[0227] Example 8A - The device of any one of examples 3A to 7A, wherein the device includes a video decoder.

[0208]

[0228] Example 9A - The device of any one of examples 3A to 8A, wherein the device includes a video encoder.

[0209]

[0229] Aspect 10A - A computer-readable storage medium storing instructions that, when executed, cause one or more processors to perform the method of any one of aspects 1A to 2A.

[0210]

[0230] Aspect 11A - A device for decoding video data, comprising: means for decoding a magnitude of a motion vector differential coordinate of a block of video data; means for decoding a motion vector code predictor index; means for constructing motion vector candidates using possible code values ​​and the magnitude of the motion vector differential coordinate; means for deriving a motion vector differential code prediction cost for each of the motion vector candidates; means for sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; means for determining a motion vector differential code based on the motion vector code predictor index and the sorted list; and means for decoding the block of video data using the magnitude of the motion vector differential coordinate and the motion vector differential code.

[0211]

[0231] Aspect 1B - A method for decoding video data, comprising: constructing motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of motion vector difference components, and a motion vector predictor for a block of video data; sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; determining a respective motion vector difference sign of each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list; and decoding the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference signs of each motion vector difference component.

[0212]

[0232] Aspect 2B - The method described in aspect 1B, in which the block of video data is coded using one of an inter-merge with motion vector differential (MMVD) mode, an affine MMVD, a geometric partitioning mode with MMVD (GPM), or a multiple hypothesis prediction (MHP) mode.

[0213]

[0233] Aspect 3B - The method of aspect 2B, wherein the block of video data is coded using inter MMVD mode, and the method further includes decoding a merge index indicating a motion vector predictor, decoding a step index indicating the magnitude of each of the motion vector difference coordinates, and decoding a motion vector code predictor index.

[0214]

[0234] Aspect 4B - The method of aspect 3B, further comprising: applying a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential; adding the motion vector differential to a motion vector predictor to determine a final motion vector; and decoding the block of video data using the final motion vector.

[0215]

[0235] Aspect 5B - The method described in aspect 2B, wherein the block of video data is coded using an affine MMVD mode and the motion vector predictor includes two or three control point motion vectors, and the method further includes determining the control point motion vectors, decoding a step index indicating the magnitude of each of the motion vector difference coordinates, and decoding a motion vector code predictor index.

[0216]

[0236] Aspect 6B - The method of aspect 5B, further comprising: applying a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential; adding the motion vector differential to each of the control point motion vectors to determine a final control point motion vector; and decoding the block of video data using the final control point motion vector.

[0217]

[0237] Embodiment 7B - The method of embodiment 1B, further comprising determining the cost using template matching.

[0218]

[0238] Aspect 8B - The method described in aspect 7B, wherein the block of video data is coded using an affine MMVD merge with motion vector difference (MMVD) mode, and determining the cost using template matching includes determining the cost using sub-block based template matching.

[0219]

[0239] Example 9B - The method of example 1B, further comprising: scaling a magnitude of each of the motion vector difference components based on a picture order count (POC) difference.

[0220]

[0240] Example 10B - The method of example 1B, further comprising displaying a picture including the decoded block of video data.

[0221]

[0241] Aspect 11B - An apparatus configured to decode video data, comprising: a memory configured to store a block of video data; and one or more processors in communication with the memory, wherein the one or more processors are configured to construct motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for the block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign of each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign of each motion vector difference component.

[0222]

[0242] Example 12B - The apparatus described in example 11B, wherein the block of video data is coded using one of an inter-merge with motion vector differential (MMVD) mode, an affine MMVD, a geometric partitioning mode with MMVD (GPM), or a multiple hypothesis prediction (MHP) mode.

[0223]

[0243] Example 13B - The apparatus described in example 12B, wherein the block of video data is coded using inter MMVD mode, and the one or more processors are further configured to decode a merge index indicating a motion vector predictor, decode a step index indicating the magnitude of each of the motion vector difference coordinates, and decode a motion vector code predictor index.

[0224]

[0244] Example 14B - The apparatus of example 13B, wherein the one or more processors are further configured to apply a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential, add the motion vector differential to a motion vector predictor to determine a final motion vector, and decode the block of video data using the final motion vector.

[0225]

[0245] Example 15B - The apparatus described in example 12B, wherein the block of video data is coded using an affine MMVD mode and the motion vector predictor includes two or three control point motion vectors, and the one or more processors are further configured to determine the control point motion vectors, decode a step index indicating the magnitude of each of the motion vector difference coordinates, and decode a motion vector code predictor index.

[0226]

[0246] Example 16B - The apparatus of example 15B, wherein the one or more processors are further configured to apply a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential, add the motion vector differential to each of the control point motion vectors to determine a final control point motion vector, and decode the block of video data using the final control point motion vector.

[0227]

[0247]

[0071] Example 17B - The apparatus of Example 11B, wherein the one or more processors are further configured to determine the cost using template matching.

[0228]

[0248] Example 18B - The apparatus described in example 17B, wherein the block of video data is coded using an affine MMVD merge with motion vector difference (MMVD) mode and, to determine the cost using template matching, the one or more processors are further configured to determine the cost using sub-block based template matching.

[0229]

[0249] Example 19B - The apparatus of example 11B, wherein the one or more processors are further configured to scale a magnitude of each of the motion vector difference components based on a picture order count (POC) difference.

[0230]

[0250]

[0041] Example 20B - The apparatus of Example 11B, further comprising: a display configured to display a picture including the decoded block of video data.

[0231]

[0251] Aspect 1C - A method for decoding video data, comprising: constructing motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of motion vector difference components, and a motion vector predictor for a block of video data; sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; determining a respective motion vector difference sign of each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list; and decoding the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference signs of each motion vector difference component.

[0232]

[0252] Aspect 2C - The method described in aspect 1C, in which the block of video data is coded using one of an inter-merge with motion vector differential (MMVD) mode, an affine MMVD, a geometric partitioning mode with MMVD (GPM), or a multiple hypothesis prediction (MHP) mode.

[0233]

[0253] Aspect 3C - The method of aspect 2C, wherein the block of video data is coded using inter MMVD mode, and the method further includes decoding a merge index indicating a motion vector predictor, decoding a step index indicating the magnitude of each of the motion vector difference coordinates, and decoding a motion vector code predictor index.

[0234]

[0254] Aspect 4C - The method described in aspect 3C, further comprising: applying a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential; adding the motion vector differential to a motion vector predictor to determine a final motion vector; and decoding the block of video data using the final motion vector.

[0235]

[0255] Aspect 5C - The method described in aspect 2C, wherein the block of video data is coded using an affine MMVD mode and the motion vector predictor includes two or three control point motion vectors, and the method further includes determining the control point motion vectors, decoding a step index indicating the magnitude of each of the motion vector difference coordinates, and decoding a motion vector code predictor index.

[0236]

[0256] The method of embodiment 6C, further comprising: applying a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential; adding the motion vector differential to each of the control point motion vectors to determine a final control point motion vector; and decoding the block of video data using the final control point motion vector.

[0237]

[0257] Embodiment 7C - The method of any one of embodiments 1C to 6C, further comprising determining the cost using template matching.

[0238]

[0258] Aspect 8C - The method described in aspect 7C, wherein the block of video data is coded using an affine MMVD merge with motion vector difference (MMVD) mode, and determining the cost using template matching includes determining the cost using sub-block based template matching.

[0239]

[0259] Example 9C - The method of any one of examples 1C to 8C, further comprising scaling a magnitude of each of the motion vector difference components based on a picture order count (POC) difference.

[0240]

[0260] Embodiment 10C - The method of any one of embodiments 1C to 9C, further comprising displaying a picture including the decoded block of video data.

[0241]

[0261] Aspect 11C - An apparatus configured to decode video data, comprising: a memory configured to store a block of video data; and one or more processors in communication with the memory, wherein the one or more processors are configured to construct motion vector candidates using possible code values ​​including positive code values ​​and negative code values, respective magnitudes of the motion vector difference components, and a motion vector predictor for the block of video data, sort the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list, determine a respective motion vector difference sign of each motion vector difference coordinate based on the motion vector sign predictor index and the sorted list, and decode the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference sign of each motion vector difference component.

[0242]

[0262] Example 12C - The apparatus described in example 11C, wherein the block of video data is coded using one of an inter-merge with motion vector differential (MMVD) mode, an affine MMVD, a geometric partitioning mode with MMVD (GPM), or a multiple hypothesis prediction (MHP) mode.

[0243]

[0263] Example 13C - The apparatus described in example 12C, wherein the block of video data is coded using inter MMVD mode, and the one or more processors are further configured to decode a merge index indicating a motion vector predictor, decode a step index indicating the magnitude of each of the motion vector difference coordinates, and decode a motion vector code predictor index.

[0244]

[0264] Example 14C - The apparatus described in example 13C, wherein the one or more processors are further configured to apply a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential, add the motion vector differential to a motion vector predictor to determine a final motion vector, and decode a block of video data using the final motion vector.

[0245]

[0265] Example 15C - The apparatus described in example 12C, wherein the block of video data is coded using affine MMVD mode and the motion vector predictor includes two or three control point motion vectors, and the one or more processors are further configured to determine the control point motion vectors, decode a step index indicating the magnitude of each of the motion vector differential coordinates, and decode a motion vector code predictor index.

[0246]

[0266] Example 16C - The apparatus described in example 15C, wherein the one or more processors are further configured to apply a respective motion vector differential sign of each motion vector differential component to a respective magnitude of the motion vector differential component to determine a motion vector differential, add the motion vector differential to each of the control point motion vectors to determine a final control point motion vector, and decode the block of video data using the final control point motion vector.

[0247]

[0267]

[0071] Example 17C - The apparatus of any one of Examples 11C to 16C, wherein the one or more processors are further configured to determine the cost using template matching.

[0248]

[0268] Example 18C - The apparatus described in example 17C, wherein the block of video data is coded using an affine MMVD merge with motion vector difference (MMVD) mode and, to determine the cost using template matching, the one or more processors are further configured to determine the cost using sub-block based template matching.

[0249]

[0269] Example 19C - The apparatus of any one of examples 11C to 18C, wherein the one or more processors are further configured to scale a magnitude of each of the motion vector difference components based on a picture order count (POC) difference.

[0250]

[0270]

[0041] Example 20C - The apparatus of any one of examples 11C to 19C, further comprising: a display configured to display a picture including the decoded block of video data.

[0251]

[0271] It should be appreciated that, depending on the example, some acts or events of any of the techniques described herein may be performed in a different order, or may be added, combined, or omitted entirely (e.g., not all acts or events described are necessary to the practice of the techniques). Moreover, in some examples, acts or events may be performed in parallel rather than sequentially, for example, through multi-threaded processing, interrupt processing, or multiple processors.

[0252]

[0272] 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 via a computer-readable medium as one or more instructions or code and executed by a hardware-based processing unit. A computer-readable medium may include a computer-readable storage medium, which corresponds to a tangible medium, such as a data storage medium, or a communication medium, which includes any medium that facilitates transfer of a computer program from one place to another, for example, according to a communication protocol. As such, a computer-readable medium may generally correspond to (1) a tangible computer-readable storage medium that is non-transitory, or (2) a communication medium, such as a signal or carrier wave. A data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and / or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

[0253]

[0273] By way of example, and not limitation, such computer-readable storage media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of media. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but instead cover non-transitory tangible storage media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer readable media.

[0254]

[0274] The instructions may be executed by one or more processors, such as one or more DSPs, general-purpose microprocessors, ASICs, FPGAs, or other equivalent integrated or discrete logic circuitry. Thus, the terms "processor" and "processing circuitry" as used herein may refer to any of the above structures, or any other structures suitable for implementing the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or may be incorporated into a combined codec. The techniques may also be fully implemented in one or more circuits or logic elements.

[0255]

[0275] The techniques of the present disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chipset). Various components, modules, or units have been described in this disclosure to highlight functional aspects of devices configured to implement the disclosed techniques, but they do not necessarily require realization by different hardware units. Rather, as described above, the various units may be combined in a codec hardware unit or may be provided by a collection of interoperable hardware units, including one or more processors as described above, in conjunction with suitable software and / or firmware.

[0256]

[0276] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. 1. A method for decoding video data, comprising: constructing motion vector candidates using possible sign values, including positive and negative sign values, magnitudes of each of the motion vector differential components, and a motion vector predictor for the block of video data; sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; determining a respective motion vector differential sign for each motion vector differential coordinate based on the sorted list and a motion vector sign predictor index indicating a motion vector candidate in the sorted list; decoding the block of video data using the respective magnitudes of motion vector difference coordinates and the respective motion vector difference signs of each motion vector difference component; A method comprising:

2. 2. The method of claim 1, wherein the blocks of video data are coded using one of an inter-merge with motion vector differential (MMVD) mode, an affine MMVD, a geometric partitioning mode with MMVD (GPM), or a multiple hypothesis prediction (MHP) mode.

3. The block of video data is coded using an inter MMVD mode, and the method comprises: decoding a merge index indicative of the motion vector predictor; decoding a step index indicating the magnitude of each of the motion vector differential coordinates; decoding the motion vector code predictor index; The method of claim 2 further comprising:

4. applying the respective motion vector differential sign of each motion vector differential component to the respective magnitude of the motion vector differential component to determine a motion vector differential; adding the motion vector differential to the motion vector predictor to determine a final motion vector; decoding the block of video data using the final motion vector; The method of claim 3 further comprising:

5. the block of video data is coded using an affine MMVD mode, the motion vector predictor includes two or three control point motion vectors, and the method comprises: determining the control point motion vectors; decoding a step index indicating the magnitude of each of the motion vector differential coordinates; decoding the motion vector code predictor index; The method of claim 2 further comprising:

6. applying the respective motion vector differential sign of each motion vector differential component to the respective magnitude of the motion vector differential component to determine a motion vector differential; adding the motion vector differential to each of the control point motion vectors to determine a final control point motion vector; decoding the block of video data using the final control point motion vector; The method of claim 5 further comprising:

7. The method of claim 1 , further comprising determining the cost using template matching.

8. the block of video data is coded using an affine MMVD merge with motion vector difference (MMVD) mode and the cost is determined using template matching; determining the cost using sub-block based template matching. The method of claim 7.

9. The method of claim 1 , further comprising scaling the magnitude of each of the motion vector difference components based on a picture order count (POC) difference.

10. The method of claim 1 , further comprising displaying a picture including the decoded blocks of video data.

11. The method of claim 1, further comprising decoding a syntax element indicating a step index for the block of video data, wherein the block of video data is encoded using an inter-merge with motion vector differential (MMVD) mode or an affine MMVD mode, the step index indicating an absolute value of a magnitude of a motion vector differential, and the motion vector differential component having the absolute value of the magnitude. determining one or more entropy decoding context models based on the absolute value of the magnitude; entropy decoding the motion vector code predictor index using the entropy decoding context model; The method of claim 11 further comprising:

13. 1. An apparatus configured to decode video data, comprising: a memory configured to store blocks of video data; one or more processors in communication with the memory; wherein the one or more processors: constructing motion vector candidates using possible sign values, including positive and negative sign values, the magnitudes of each of the motion vector differential components, and a motion vector predictor for the block of video data; sorting the motion vector candidates based on a cost for each of the motion vector candidates to create a sorted list; determining a respective motion vector differential sign for each motion vector differential coordinate based on the sorted list and a motion vector sign predictor index indicating a motion vector candidate in the sorted list; decoding the block of video data using the respective magnitudes of the motion vector difference coordinates and the respective motion vector difference signs of each motion vector difference component; It is configured as follows: Device.

14. 14. The apparatus of claim 13, wherein the block of video data is coded using one of an inter-merge with motion vector differential (MMVD) mode, an affine MMVD, a geometric partitioning mode with MMVD (GPM), or a multiple hypothesis prediction (MHP) mode.

15. The apparatus of claim 13, further comprising means for carrying out the method of any one of claims 3 to 12.

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