History-based motion vector prediction constraint for merge estimation region

Abstract

An apparatus for decoding video data can be configured to store a history-based motion vector predictor (HMVP) table, determine motion information for a first block of video data, add the motion information for the first block to the HMVP table in response to determining that the first block is located at a lower right corner of a motion estimation region (MER), and decode a second block of video data using the HMVP table.

Description

[0001] This application claims priority to U.S. Application No. 17 / 136,983, filed December 29, 2020, which claims the benefit of U.S. Provisional Patent Application No. 62 / 955,977, filed December 31, 2019, the entire contents of each of which are incorporated herein by reference. Technical Field

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

[0003] Digital video functionality can be integrated into a wide variety of devices, including digital televisions, digital direct broadcasting systems, wireless broadcasting systems, personal digital assistants (PDAs), laptops or desktop computers, tablets, e-book readers, digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio phones, so-called "smartphones," video conferencing equipment, video streaming devices, and more. Digital video devices implement video decoding technologies such as MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4, Part 10, Advanced Video Decoding (AVC), ITU-T H.265 / High-Efficiency Video Decoding (HEVC), and extensions to these standards. By implementing such video decoding technologies, video devices can more efficiently transmit, receive, encode, decode, and / or store digital video information.

[0004] Video decoding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or eliminate inherent redundancy in video sequences. For block-based video decoding, video segments (e.g., video pictures or portions of video pictures) can be divided into video blocks, which may also be referred to as decoding tree units (CTUs), decoding units (CUs), and / or decoding nodes. Spatial prediction is used to encode video blocks in intra-frame decoded (I) segments of a picture relative to reference samples in adjacent blocks within the same picture. Video blocks in inter-frame decoded (P or B) segments of a picture can use spatial prediction relative to reference samples in adjacent blocks within the same picture, or temporal prediction relative to reference samples in other reference pictures. A picture can be referred to as a frame, and a reference picture can be referred to as a reference frame. Summary of the Invention

[0005] Merge Estimation Region (MER) typically refers to a region of one or more blocks, where the video encoder and video decoder can derive a merge candidate list of blocks for the region in parallel. As explained in more detail below, existing implementations of History-Based Motion Vector Prediction Factor (HMVP) can prevent parallelization of the merge candidate list derivation implemented using MER. Therefore, existing implementations of HMVP may not be compatible with MER. This disclosure describes a technique for maintaining an HPV table in a manner that enables HPV to be used in conjunction with MER. Specifically, by adding the motion information of a block to the HPV table in response to determining that the first block is located at the lower right corner of the MER, the video encoder and video decoder can simultaneously implement HPV while implementing parallelization of MER.

[0006] According to one example, a method for decoding video data includes: storing a table of historical motion vector predictors (HMVP); determining motion information for a first block of video data; adding the motion information of the first block to the HMVP table in response to determining that the first block is located in the lower right corner of a motion estimation region (MER); and using the HMVP table to decode a second block of video data.

[0007] According to another example, an apparatus for decoding video data includes: a memory configured to store video data; and one or more processors implemented in a circuit and configured to store a table of history-based motion vector predictors (HMVP); determining motion information of a first block of video data; adding the motion information of the first block to the HMVP table in response to determining that the first block is located in the lower right corner of a motion estimation region (MER); and using the HMVP table to decode a second block of video data.

[0008] According to another example, a computer-readable storage medium stores instructions that, when executed by one or more processors, cause the one or more processors to: store a table of history-based motion vector predictors (HMVP); determine motion information for a first block of video data; add the motion information of the first block to the HMVP table in response to determining that the first block is located in the lower right corner of a motion estimation region (MER); and use the HMVP table to decode a second block of video data.

[0009] According to another example, an apparatus for decoding video data includes a unit for storing a table of historical motion vector predictors (HMVP); a unit for determining motion information of a first block of video data; a unit for adding the motion information of the first block to the HMVP table in response to determining that the first block is located in the lower right corner of a motion estimation region (MER); and a unit for using the HMVP table to decode a second block of video data.

[0010] Details of one or more examples are set forth in the accompanying drawings and the following description. Other features, objects, and advantages will be apparent from the description, the drawings, and the claims. Attached Figure Description

[0011] Figure 1 This is a block diagram illustrating an example video encoding and decoding system that can perform the techniques described in this disclosure.

[0012] Figure 2A and Figure 2B This is a conceptual diagram showing an example quadtree binary tree (QTBT) structure and its corresponding decoding tree unit (CTU).

[0013] Figure 3 This is a conceptual diagram showing an example of a merged estimation region.

[0014] Figure 4 This is a block diagram illustrating an example video encoder that can perform the techniques described in this disclosure.

[0015] Figure 5 This is a block diagram illustrating an example video decoder that can perform the techniques described in this disclosure.

[0016] Figure 6 This is a flowchart illustrating an example video encoding process.

[0017] Figure 7 This is a flowchart illustrating an example video decoding process.

[0018] Figure 8 This is a flowchart illustrating an example video decoding process. Detailed Implementation

[0019] Video decoding (e.g., video encoding and / or video decoding) typically involves predicting video data blocks from decoded video data blocks in the same frame (e.g., intra-frame prediction) or from decoded video data blocks in different frames (e.g., inter-frame prediction). In some cases, the video encoder also computes residual data by comparing the predicted block with the original block. Therefore, the residual data represents the difference between the predicted block and the original block. To reduce the number of bits required to signal the residual data, the video encoder transforms and quantizes the residual data, and signals the transformed and quantized residual data in the encoded bitstream. Compression achieved through the transformation and quantization process can be lossy, meaning that the transformation and quantization process can introduce distortion into the decoded video data.

[0020] The video decoder decodes the residual data and adds it to the prediction block to produce a reconstructed video block that matches the original video block more closely than a single prediction block. The first reconstructed block may have distortion or artifacts due to losses introduced by transforming and quantizing the residual data. A common type of artifact or distortion is called block artifacts, where the boundaries of the blocks used to decode the video data are visible.

[0021] To further improve the quality of the decoded video, the video decoder may perform one or more filtering operations on the reconstructed video blocks. Examples of these filtering operations include deblocking filtering, Sample Adaptive Offset (SAO) filtering, and Adaptive Loop Filtering (ALF). The parameters used for these filtering operations may be determined by the video encoder and explicitly signaled in the encoded video bitstream, or they may be implicitly determined by the video decoder without needing to be explicitly signaled in the encoded video bitstream.

[0022] As will be described in more detail below, when using inter-frame prediction to decode video data blocks, the video encoder and video decoder can be configured to decode the blocks in various modes. One such mode is the merge mode. In merge mode, the video encoder and video decoder are configured to generate a merge candidate list, where each merge candidate in the list includes motion information for predicting the block. For example, the motion information may include one or more motion vectors and one or more reference image identifiers.

[0023] By implementing the same list generation process and using only available information from decoded blocks, video encoders and video decoders can be configured to generate the same list of merge candidates with the same order. Therefore, for a video encoder that signals motion information in merge mode, the video encoder can include an index in the encoded bitstream that identifies one of the merge candidates. Since the video decoder has constructed the same list as the video encoder, it can determine the motion information associated with the merge candidate, which is associated with the received index. In merge mode, the video decoder determines prediction blocks based on the motion information associated with the merge candidate, which is associated with the received index.

[0024] Video encoders and decoders can generate a list of merge candidates for a block by adding motion information from spatially adjacent blocks in the same image as the block, blocks at the same location in different images, manually generated candidates, default candidates, or other such candidates in a predefined order. In some cases, video encoders and decoders can also be configured to add history-based candidates, which may include previously used motion information that does not correspond to spatially adjacent blocks or blocks at the same location. To determine history-based candidates, video encoders and decoders can each maintain (e.g., store and update) a history-based motion vector prediction HMVP table. Video encoders and decoders can store a predefined number of motion vectors in the HMVP table. When a new motion vector is added to the HMVP table, older motion vectors can be removed (e.g., in a first-in, first-out manner). In some cases, video encoders and decoders can be configured to add motion information from entries in the HMVP table to the merge candidate list used to merge decoded video blocks.

[0025] The video encoder and video decoder can also be configured to decode blocks using merged estimation regions (MERs) in the images of the video data. The video encoder and / or video decoder can be configured to perform merged mode motion vector prediction processes (e.g., motion vector predictor list construction, such as merged candidate list construction) in parallel for multiple blocks (e.g., decoding units) within the MER.

[0026] As will be explained in more detail below, existing implementations of HMVP can prevent parallelization of the merge candidate list derived using MER. Therefore, existing implementations of HMVP may not be compatible with MER. This disclosure describes techniques for maintaining an HMVP table in a manner that enables HMVP to be used in conjunction with MER. Specifically, by adding the motion information of a block to the HMVP table in response to determining that the first block is located at the lower right corner of the motion estimation region, the video encoder and video decoder can simultaneously implement both HMVP and MER.

[0027] As used in this disclosure, the term video decoding generally refers to video encoding or video decoding. Similarly, the term video decoder may generally refer to video encoder or video decoder. Furthermore, some of the techniques described in this disclosure regarding video decoding can also be applied to video encoding, and vice versa. For example, video encoders and video decoders are typically configured to perform the same or inverse processes. For instance, both video encoders and video decoders may be configured to use the same rules to generate an HMVP table, such that both maintain the same HMVP table without any significant signaling overhead. Additionally, video encoders typically perform video decoding (also known as reconstruction) as part of the process of determining how to encode video data.

[0028] Figure 1 This is a block diagram illustrating an exemplary video encoding and decoding system 100 capable of performing the techniques of this disclosure. The techniques of this disclosure are generally aimed at decoding (encoding and / or decoding) video data. Typically, video data includes any data used for processing video. Therefore, video data can include raw, unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0029] like Figure 1 As shown, 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 can include any of a variety of devices, including desktop computers, laptops, mobile devices, tablets, set-top boxes, mobile phones (e.g., smartphones), televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, broadcast receivers, etc. In some cases, source device 102 and destination device 116 may be equipped for wireless communication and therefore may be referred to as wireless communication devices.

[0030] exist Figure 1 In the example, source device 102 includes a video source 104, memory 106, a video encoder 200, and an 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 of source device 102 and the video decoder 300 of destination device 116 can be configured to apply the techniques disclosed herein for updating HMVP tables. Therefore, 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 and destination devices may include other components or arrangements. For example, source device 102 may receive video data from an external video source such as an external camera. Similarly, destination device 116 may be connected to an external display device, rather than including an integrated display device.

[0031] like Figure 1The system 100 shown is merely an example. Typically, any digital video encoding and / or decoding device can perform the techniques disclosed herein for updating the HMVP table. The source device 102 and destination device 116 are merely examples of such decoding devices, where the source device 102 generates decoded video data for transmission to the destination device 116. This disclosure refers to a “decoding” device as a device that performs the decoding (encoding and / or decoding) of data. Thus, video encoder 200 and video decoder 300 represent examples of decoding devices, specifically a video encoder and a video decoder. In some examples, the source device 102 and destination device 116 may operate in a substantially symmetrical manner, such that each of the source device 102 and destination device 116 includes video encoding and decoding components. Therefore, system 100 can support one-way or two-way video transmission between the source device 102 and destination device 116, for example, for video streaming, video playback, video broadcasting, or video telephony.

[0032] Typically, video source 104 represents a source of video data (i.e., raw, unencoded video data) and provides a sequence of pictures (also called “frames”) of the video data to video encoder 200 for encoding the pictures. Video source 104 of source device 102 may include video capture devices, such as cameras, video archives containing previously captured raw video, and / or video feed interfaces to receive video from video content providers. Alternatively, 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, pre-captured, or computer-generated video data. Video encoder 200 may rearrange the pictures from the received order (sometimes referred to as “display order”) to an encoding order for encoding. Video encoder 200 may generate a bitstream including the encoded video data. Source device 102 may then output the encoded video data to computer-readable medium 110 via output interface 108 for reception and / or retrieval via input interface 122 of destination device 116, for example.

[0033] The memory 106 of source device 102 and the memory 120 of destination device 116 represent general-purpose memory. In some examples, memories 106 and 120 may store raw video data, such as raw video from video source 104 and raw decoded video data from video decoder 300. Alternatively or additionally, memories 106 and 120 may store software instructions that can be executed by, for example, video encoder 200 and video decoder 300 respectively. Although memories 106 and 120 are shown separately from video encoder 200 and video decoder 300 in this example, it should be understood that video encoder 200 and video decoder 300 may also include internal memory for functionally similar or equivalent purposes. Furthermore, memories 106 and 120 may store, for example, encoded video data output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106 and 120 may be allocated as one or more video buffers, for example, to store raw, decoded, and / or encoded video data.

[0034] Computer-readable medium 110 can represent any type of medium or device capable of transmitting encoded video data from source device 102 to destination device 116. In one example, computer-readable medium 110 represents a communication medium enabling source device 102 to transmit encoded video data directly to destination device 116 in real time, for example, via a radio frequency network or a computer-based network. According to a communication standard such as a wireless communication protocol, output interface 108 can modulate the transmitted signal including the encoded video data, and input interface 122 can demodulate the received transmitted signal. The communication medium can include any wireless or wired communication medium, such as radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium can form part of a packet-based network such as a local area network (LAN), a wide area network (WAN), or a global network such as the Internet. The communication medium can include a router, switch, base station, or any other device that can be used to facilitate communication from source device 102 to destination device 116.

[0035] In some examples, source device 102 can output encoded data to storage device 112 from output interface 108. Similarly, destination device 116 can access 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 hard disk drives, Blu-ray discs, DVDs, CD-ROMs, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data.

[0036] In some examples, source device 102 can output encoded video data to file server 114 or another intermediate storage device that can store the encoded video data generated by source device 102. Destination device 116 can access the stored video data from file server 114 via streaming or downloading.

[0037] File server 114 can be any type of server device capable of storing encoded video data and transmitting such encoded video data to destination device 116. File server 114 can 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 One-Way File Delivery (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. File server 114 can additionally or alternatively implement one or more HTTP streaming protocols, such as HTTP-based Dynamic Adaptive Streaming (DASH), HTTP Live Streaming (HLS), Real-Time Streaming Protocol (RTSP), HTTP Dynamic Streaming, etc.

[0038] Destination device 116 can access encoded video data from file server 114 via any standard data connection, including an internet connection. This can include a wireless channel (e.g., Wi-Fi connection), a wired connection (e.g., Digital Subscriber Line (DSL), cable modem, etc.), or a combination of both, suitable for accessing encoded video data stored on file server 114. Input interface 122 can be configured to operate according to any one or more of the various protocols described above for retrieving or receiving media data from file server 114, or other such protocols for retrieving media data.

[0039] Output interface 108 and input interface 122 may represent a wireless transmitter / receiver, a modem, a wired networking component (e.g., an Ethernet card), a wireless communication component operating according to any of the various IEEE 802.11 standards, or other physical components. In examples where output interface 108 and input interface 122 include wireless components, output interface 108 and input interface 122 may be configured to transmit 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 where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 may be configured to operate according to other wireless standards (e.g., the IEEE 802.11 specification, the IEEE 802.15 specification, or ZigBee). TM),Bluetooth TM Standards, etc., are used to transmit data such as encoded video data. In some examples, source device 102 and / or destination device 116 may include their respective system-on-a-chip (SoC) devices. For example, source device 102 may include an SoC device to perform functions belonging to video encoder 200 and / or output interface 108, and destination device 116 may include an SoC device to perform functions belonging to video decoder 300 and / or input interface 122.

[0040] The technology disclosed herein can be applied to video decoding that supports any of a variety of multimedia applications, such as over-the-air television broadcasting, cable television transmission, satellite television transmission, internet streaming video transmission (e.g., Dynamic Adaptive Streaming (DASH) via HTTP), digital video encoded onto data storage media, decoding digital video stored on data storage media, or other applications.

[0041] The input interface 122 of the destination device 116 receives an encoded video bitstream from a computer-readable medium 110 (e.g., a communication medium, storage device 112, file server 114, etc.). The encoded video bitstream may include signaling information defined by the video encoder 200, which is also used by the video decoder 300, such as syntax elements having values ​​describing the characteristics and / or processing of video blocks or other decoding units (e.g., segments, pictures, picture groups, sequences, etc.). The display device 118 displays decoded images of the decoded video data to the 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.

[0042] Although not in Figure 1 As shown, but in some examples, the video encoder 200 and video decoder 300 may each be integrated with the audio encoder and / or audio decoder, and may include appropriate MUX-DEMUX units or other hardware and / or software to process multiplexed streams that include both audio and video in a common data stream. Where applicable, the MUX-DEMUX unit may conform to the ITU H.223 multiplexer protocol or other protocols, such as User Datagram Protocol (UDP).

[0043] The video encoder 200 and video decoder 300 can 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 technology is implemented in part in software, the device may store instructions for software in a suitable non-transitory computer-readable medium and use one or more processors to execute the instructions in hardware to perform the technology of this disclosure. Each of the video encoder 200 and video decoder 300 may be included in one or more encoders or decoders, and any of them may be integrated as part of a combined encoder / decoder (CODEC) in the respective device. Devices including the video encoder 200 and / or video decoder 300 may include integrated circuits, microprocessors, and / or wireless communication devices, such as cellular phones.

[0044] The video encoder 200 and video decoder 300 can operate according to video coding standards such as ITU-T H.265, also known as High Efficiency Video Coding (HEVC) or its extensions, such as Multiview and / or Scalable Video Coding Extensions. Alternatively, the video encoder 200 and video decoder 300 can operate according to other proprietary or industry standards such as the Joint Exploratory Test Model (JEM) or ITU-T H.266 (also known as Versatile Video Coding (VVC)). Bross et al. described the latest draft of the VVC standard: “Versatile Video Coding (Draft 7),” Joint Video Experts Group (JVET) of ITU-T SG 16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 16th meeting: Geneva, CH, October 1-11, 2019, JVET-P2001-v14 (hereinafter referred to as “VVC Draft 7”). Bross et al. described another draft of the VVC standard: “Versatile Video Coding (Draft 10)”, 18th meeting of the Joint Video Experts Group (JVET) of ITU-T SG 16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11: Teleconference, 22 June–1 July 2020, JVET-S2001-v17 (hereinafter referred to as “VVC Draft 10”). However, the technology of this disclosure is not limited to any particular coding standard.

[0045] Typically, video encoder 200 and video decoder 300 can perform block-based decoding of images. The term "block" generally refers to a structure that includes the data to be processed (e.g., encoded, decoded, or otherwise used during encoding and / or decoding processes). For example, a block may include a two-dimensional matrix of samples of luminance and / or chrominance data. Typically, video encoder 200 and video decoder 300 can decode video data represented in YUV (e.g., Y, Cb, Cr) format. That is, instead of decoding the red, green, and blue (RGB) data of samples of an image, video encoder 200 and video decoder 300 can decode the luminance and chrominance components, where the chrominance components may include red and blue chrominance components. In some examples, video encoder 200 converts the received RGB format data to a YUV representation before encoding, and video decoder 300 converts the YUV representation back to RGB format. Alternatively, preprocessing and post-processing units (not shown) can perform these conversions.

[0046] This disclosure can generally relate to the decoding (e.g., encoding and decoding) of images to include the process of encoding or decoding image data. Similarly, this disclosure can relate to the decoding of blocks of images to include the process of encoding or decoding block data, such as prediction and / or residual decoding. Encoded video bitstreams typically include a series of values ​​for syntax elements that represent decoding decisions (e.g., decoding modes) and the partitioning of images into blocks. Therefore, references to decoding images or blocks should generally be understood as decoding the values ​​of syntax elements used to form images or blocks.

[0047] HEVC defines various blocks, including decoding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video decoder (e.g., a video encoder 200) divides the decoding tree unit (CTU) into CUs according to a quadtree structure. That is, the video decoder divides the CTU and CU into four equal, non-overlapping squares, with each node of the quadtree having zero or four child nodes. Nodes without child nodes can be called "leaf nodes," and the CU of such leaf nodes can include one or more PUs and / or one or more TUs. The video decoder can further divide the PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents the partitioning of TUs. In HEVC, PUs represent inter-frame prediction data, while TUs represent residual data. CUs for intra-frame prediction include intra-frame prediction information, such as intra-frame mode indication.

[0048] As another example, video encoder 200 and video decoder 300 can be configured to operate according to VVC. According to VVC, the video decoder (e.g., video encoder 200) partitions the image into multiple decoding tree units (CTUs). Video encoder 200 can partition the CTUs according to a tree structure such as a quadtree-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 quadtree 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 decoding units (CUs).

[0049] In the MTT partitioning structure, blocks can be partitioned using quadtree (QT), binary tree (BT), and one or more types of ternary tree (TT) partitioning (also known as tripartite tree (TT)). A ternary tree partition divides a block into three sub-blocks. In some examples, a ternary tree partition divides a block into three sub-blocks without splitting the original block by a center. The partitioning types in MTT (such as QT, BT, and TT) can be symmetric or asymmetric.

[0050] 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 the two chroma components (or two QTBT / MTT structures for each chroma component).

[0051] The video encoder 200 and video decoder 300 can be configured to use quadtree partitioning for each HEVC, QTBT, MTT, or other partitioning structure. For illustrative purposes, the techniques of this disclosure are described with respect to QTBT partitioning. However, it should be understood that the techniques of this disclosure can also be applied to video decoders configured to use quadtree partitioning or other types of partitioning.

[0052] In some examples, a CTU includes a decoded tree block (CTB) of luminance samples, two corresponding CTBs of chrominance samples of an image with three sample arrays, or a CTB of samples of a monochrome image or an image decoded using three separate color planes and syntax structures for decoding the samples. A CTB can be an N×N sample block of some value N such that dividing the components into CTBs is a partition. A component is an array or a single sample from one of the three arrays (luminance and two chrominance) constituting an image in a 4:2:0, 4:2:2, or 4:4:4 color format, or an array or a single sample from an array constituting an image in monochrome format. In some examples, a decoded block is an M×N sample block of some values ​​M and N such that dividing the CTB into decoded blocks is a partition.

[0053] Blocks can be grouped in various ways within an image (e.g., CTUs or CUs). As an example, a block can refer to a rectangular area of ​​a row of CTUs within a specific tile in an image. A tile can be a rectangular area of ​​CTUs within a specific tile column and a specific tile row in an image. A tile column refers to a rectangular area of ​​CTUs with a height equal to the height of the image and a width specified by a syntax element (e.g., in the image parameter set). A tile row refers to a rectangular area of ​​CTUs with a height specified by a syntax element (e.g., in the image parameter set) and a width equal to the width of the image.

[0054] In some examples, a tile can be divided into multiple blocks, each block comprising one or more CTU rows within that tile. A convexity that is not divided into multiple blocks can also be called a block. However, a block that is a proper subset of a convexity may not be called a convexity.

[0055] You can also arrange blocks from an image into slices. A slice can be an integer number of blocks from an image, and it can be uniquely contained within a single Network Abstraction Layer (NAL) unit. In some examples, a slice consists of multiple complete tiles or a continuous sequence of complete blocks that contain only one tile.

[0056] This disclosure uses "N×N" and "N by N" interchangeably to refer to the sample size of a block (e.g., a CU or other video block) according to its vertical and horizontal dimensions, such as 16×16 samples or 16 by 16 samples. Typically, a 16×16 CU has 16 samples in the vertical direction (y = 16) and 16 samples in the horizontal direction (x = 16). Similarly, an N×N CU typically has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non-negative integer value. Samples in a CU can be arranged in rows and columns. Furthermore, a CU does not necessarily have the same number of samples in the horizontal direction as it does in the vertical direction. For example, a CU may include N×M samples, where M is not necessarily equal to N.

[0057] The video encoder 200 encodes video data containing CUs (Complex Units) representing prediction and / or residual information, as well as other information. The prediction information indicates how the CUs will be predicted to form prediction blocks for the CUs. The residual information typically represents the sample-by-sample difference between the CU samples before encoding and the prediction blocks.

[0058] To predict the Cues (CUs), the video encoder 200 typically forms prediction blocks for the CUs through inter-frame prediction or intra-frame prediction. Inter-frame prediction typically refers to predicting the CUs based on data from previously encoded images, while intra-frame prediction typically refers to predicting the CUs based on previously encoded data from the same image. To perform inter-frame prediction, the video encoder 200 can use one or more motion vectors to generate prediction blocks. The video encoder 200 can typically perform a motion search, for example, based on the difference between the CU and a reference block, to identify a reference block that closely matches the CU. The video encoder 200 can calculate a difference metric using the sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), or other such difference calculations to determine whether the reference block closely matches the current CU. In some examples, the video encoder 200 can use unidirectional or bidirectional prediction to predict the current CU.

[0059] The video encoder 200 can signal motion parameters of a block in various ways. These motion parameters may include motion vectors, reference indices, reference picture list indicators, and / or other motion-related data. In some examples, the video encoder 200 and video decoder 300 may use motion prediction to reduce the amount of data used to signal motion parameters. Motion prediction may involve determining the motion parameters of a block (e.g., PU, ​​CU, etc.) based on the motion parameters of one or more other blocks. Various types of motion prediction exist. For example, merge mode and Advanced Motion Vector Prediction (AMVP) mode are two types of motion prediction.

[0060] In merge mode, video encoder 200 generates a candidate list. The candidate list includes a set of candidates indicating motion parameters of one or more source blocks. Source blocks may be spatially or temporally adjacent to the current block. Furthermore, in merge mode, video encoder 200 can select a candidate from the candidate list and use the motion parameters indicated by the selected candidate as the motion parameters for the current block. Video encoder 200 can signal the position of the selected candidate in the candidate list. Video decoder 300 can determine the index in the candidate list based on information obtained from the bitstream. Alternatively, video decoder 300 can generate the same candidate list and determine the selected candidate based on the index. Video decoder 300 can then use the motion parameters of the selected candidate to generate a predictor block for the current block.

[0061] Skip mode is similar to merge mode. In skip mode, video encoder 200 and video decoder 300 generate a candidate list and use it in the same way as in merge mode. However, when video encoder 200 signals the motion parameters of the current block using skip mode, it does not signal any residual data of the current block. Therefore, video decoder 300 can determine the prediction factor block of the current block based on one or more reference blocks indicated by the motion parameters of the selected candidates in the candidate list. Video decoder 300 can then reconstruct samples in the decoded block of the current block such that the reconstructed samples are equal to the corresponding samples in the prediction factor block of the current block.

[0062] The AMVP mode is similar to the merge mode because the video encoder 200 can generate a candidate list for the current block and select candidates from the list. However, for each corresponding reference block used in the predictor block that determines the current block, the video encoder 200 can signal the corresponding motion vector difference (MVD) of the current block, the corresponding reference index of the current block, and the corresponding candidate index indicating the selected candidate from the candidate list. The MVD of the block indicates the difference between the motion vector of the block and the motion vector of the selected candidate. The reference index of the current block indicates a reference image from which the reference block is determined.

[0063] Furthermore, when using the AMVP mode, for each corresponding reference block used in determining the predictor block of the current block, the video decoder 300 can determine the MVD of the current block, the reference index of the current block, and the candidate index and motion vector prediction MVP flag. The video decoder 300 can generate the same candidate list and can determine the selected candidate in the candidate list based on the candidate index. As previously described, the candidate list may include motion vectors of neighboring blocks associated with the same reference index and temporal motion vector prediction factors derived from motion parameters of neighboring blocks at the same location in the temporal reference picture. The video decoder 300 can recover the motion vector of the current block by adding the MVD to the motion vector indicated by the selected AMVP candidate. That is, the video decoder 300 can determine the motion vector of the current block based on the motion vector indicated by the selected AMVP candidate and the MVD. The video decoder 300 can then use one or more recovered motion vectors of the current block to generate the predictor block of the current block.

[0064] When a video decoder (e.g., video encoder 200 or video decoder 300) generates an AMVP candidate list for the current block, the video decoder may derive one or more AMVP candidates based on motion parameters of reference blocks (e.g., spatially adjacent blocks) that are spatially adjacent to the current PU, and one or more AMVP candidates based on motion parameters of PUs that are temporally adjacent to the current PU. The candidate list may include motion vectors of reference blocks associated with the same reference index and temporal motion vector predictors derived from motion parameters (i.e., motion parameters) of adjacent blocks at the same location in a temporal reference picture. Candidates in the merged candidate list or AMVP candidate list are based on motion parameters of reference blocks that are temporally adjacent to the current block. This disclosure may use the term "temporal motion vector predictor" to refer to a block that is in a different temporal instance than the current block and is used for motion vector prediction.

[0065] Some examples of VVC also provide affine motion compensation modes, which can be viewed as inter-frame prediction modes. In affine motion compensation mode, the video encoder 200 can determine two or more motion vectors representing non-translational motion (such as zooming in or out, rotation, perspective motion, or other irregular motion types).

[0066] To perform intra-frame prediction, the video encoder 200 can select an intra-frame prediction mode to generate prediction blocks. Some examples of VVC provide 67 intra-frame prediction modes, including various directional modes, as well as planar and DC modes. Typically, the video encoder 200 selects an intra-frame prediction mode that describes the neighboring samples to the current block (e.g., a block of a CU) and predicts samples for the current block from them. Assuming the video encoder 200 encodes the CTU and CU in raster scan order (from left to right, from top to bottom), such samples can typically be located above, above, to the left, or to the right of the current block in the same image.

[0067] The video encoder 200 encodes data representing the prediction mode of the current block. For example, for inter-frame prediction modes, the video encoder 200 may encode data indicating which of the various available inter-frame prediction modes is used, along with the motion information for the corresponding mode. For unidirectional or bidirectional inter-frame prediction, for example, the video encoder 200 may use AMVP or merge modes to encode motion vectors. The video encoder 200 may use similar modes to encode motion vectors for affine motion compensation modes.

[0068] Following a prediction, such as intra-frame or inter-frame prediction of a block, the video encoder 200 can compute residual data for that block. The residual data (e.g., a residual block) represents the sample-by-sample difference between that block and its predicted block formed using the corresponding prediction mode. The video encoder 200 can apply one or more transforms to the residual block to produce transformed data in the transform domain rather than the sample domain. For example, the video encoder 200 can apply a Discrete Cosine Transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform to the residual video data. Additionally, the video encoder 200 can apply a secondary transform after the first transform, such as a mode-dependent inseparable secondary transform (MDNSST), a signal-dependent transform, a Karhunen-Loeve transform (KLT), etc. The video encoder 200 produces transform coefficients after applying one or more transforms.

[0069] As described above, after any transformation used to generate the transform coefficients, the video encoder 200 may perform quantization of the transform coefficients. Quantization generally refers to the process of quantizing transform coefficients to potentially reduce the amount of data used to represent them, thereby providing further compression. By performing the 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 round 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.

[0070] After quantization, the video encoder 200 can scan the transform coefficients to produce a one-dimensional vector from a two-dimensional matrix including the quantized transform coefficients. The scan can be designed to place higher-energy (and therefore lower-frequency) transform coefficients before the vector and lower-energy (and therefore higher-frequency) transform coefficients after the vector. In some examples, the video encoder 200 can utilize a predefined scan order to scan the quantized transform coefficients to produce a serialized vector, and then entropy-encode the quantized transform coefficients of the vector. In other examples, the video encoder 200 can perform an adaptive scan. After scanning the quantized transform coefficients to form a one-dimensional vector, the video encoder 200 can entropy-encode the one-dimensional vector, for example, according to context-adaptive binary arithmetic coding (CABAC). The video encoder 200 can also entropy-encode the values ​​of syntax elements that describe metadata associated with the encoded video data for use by the video decoder 300 when decoding the video data.

[0071] To perform CABAC, the video encoder 200 can assign context within a context model to the symbols to be transmitted. Context may involve, for example, whether the neighboring values ​​of a symbol are zero. Probability determination can be based on the context assigned to the symbols.

[0072] The video encoder 200 may also generate syntax data for the video decoder 300, for example, in image headers, block headers, or segment headers. This syntax data may include block-based syntax data, image-based syntax data, and sequence-based syntax data, or other syntax data such as sequence parameter sets (SPS), picture parameter sets (PPS), or video parameter sets (VPS). The video decoder 300 may similarly decode this syntax data to determine how to decode the corresponding video data.

[0073] In this manner, the video encoder 200 can generate a bitstream that includes encoded video data, such as syntax elements describing the division of images into blocks (e.g., CUs) and prediction and / or residual information for the blocks. Finally, the video decoder 300 can receive the bitstream and decode the encoded video data.

[0074] Typically, video decoder 300 performs the inverse process of video encoder 200 to decode encoded video data of the bitstream. For example, video decoder 300 can use CABAC to decode the values ​​of syntax elements of the bitstream in a manner that is inverse but fundamentally similar to the CABAC encoding process of video encoder 200. Syntax elements can define partitioning information for dividing a picture into CTUs, dividing each CTU according to a corresponding partitioning structure (e.g., QTBT structure) to define the CUs of the CTUs. Syntax elements can further define prediction and residual information for blocks (e.g., CUs) of video data.

[0075] The residual information can be represented, for example, by quantized transform coefficients. The video decoder 300 can inversely quantize and inversely transform the quantized transform coefficients of the block to reproduce the residual block of that block. The video decoder 300 uses the signal-informed prediction mode (intra-frame or inter-frame prediction) and associated prediction information (e.g., motion information for inter-frame prediction) to form a prediction block for that block. The video decoder 300 can then combine the prediction block and the residual block (on a sample-by-sample basis) to reproduce the original block. The video decoder 300 can perform additional processing, such as performing deblocking processing to reduce visual artifacts along the block boundaries.

[0076] This disclosure may generally refer to "signaling" certain information, such as syntax elements. The term "signaling" can generally refer to the communication of values ​​for syntax elements and / or other data used to decode encoded video data. That is, video encoder 200 can signal the values ​​of syntax elements in the bitstream. Generally, signaling refers to generating values ​​in the bitstream. As described above, source device 102 can transmit the bitstream to destination device 116 substantially in real-time or non-real-time (such as when storing syntax elements to storage device 112 for later retrieval by destination device 116).

[0077] Figure 2A and Figure 2B This is a conceptual diagram illustrating an exemplary Quadtree Binary Tree (QTBT) structure 130 and its corresponding Decoding Tree Unit (CTU) 132. Solid lines represent quadtree splits, while dashed lines represent binary tree splits. In each split (i.e., non-leaf) node of the binary tree, a flag is signaled to indicate which split type (i.e., horizontal or vertical) is used; in this example, 0 indicates a horizontal split and 1 indicates a vertical split. For quadtree splits, since a quadtree node splits a block horizontally and vertically into four equal-sized sub-blocks, there is no need to indicate the split type. Therefore, the video encoder 200 can encode and the video decoder 300 can decode syntax elements (e.g., split information) at the region tree level (i.e., solid lines) and the prediction tree level (e.g., dashed lines) of the QTBT structure 130. The video encoder 200 can encode and the video decoder 300 can decode video data, such as prediction and transform data, for the CUs represented by the terminal leaf nodes of the QTBT structure 130.

[0078] Generally speaking, Figure 2B The CTU 132 can be associated with parameters that define the size of the block corresponding to the nodes of the QTBT structure 130 at the first and second levels. These parameters can include the CTU size (representing the size of the CTU 132 in the sample), the minimum quadtree size (MinQTSize, representing the minimum allowed size of the leaf nodes of a quadtree), the maximum binary tree size (MaxBTSize, representing the maximum allowed size of the root node of a binary tree), the maximum binary tree depth (MaxBTDepth, representing the maximum allowed depth of a binary tree), and the minimum binary tree size (MinBTSize, representing the minimum allowed size of the leaf nodes of a binary tree).

[0079] The root node of a QTBT structure corresponding to a CTU can have four child nodes at the first level of the QTBT structure, each child node being partitioned according to a quadtree partition. That is, the nodes at the first level are leaf nodes (with no child nodes) or have four child nodes. An example of QTBT structure 130 represents such a node as having a parent node and child nodes with solid lines for branching. If the nodes at the first level are not larger than the maximum allowed binary tree root node size (MaxBTSize), then the nodes can subsequently be further partitioned by the corresponding binary tree. The binary tree split of a node can be iterated until the nodes resulting from the split reach the minimum allowed binary tree leaf node size (MinBTSize) or the maximum allowed binary tree depth (MaxBTDepth). An example of QTBT structure 130 represents such a node as having dashed lines for branching. The binary tree leaf nodes are called decoding units (CUs), which are used for prediction (e.g., intra-frame prediction or inter-frame prediction) and transformation without any further partitioning. As mentioned above, CUs can also be referred to as “video blocks” or “blocks”.

[0080] In one example of a QTBT partitioning structure, the CTU size is set to 128×128 (luminance samples and two corresponding 64×64 chrominance samples), the MinQTSize is set to 16×16, the MaxBTSize is set to 64×64, the MinBTSize (for width and height) is set to 4, and the MaxBTDepth is set to 4. Quadtree partitioning is first applied to the CTU to generate quadtree leaf nodes. The size of the quadtree leaf nodes can range from 16×16 (i.e., MinQTSize) to 128×128 (i.e., the CTU size). If a quadtree leaf node is 128×128, it will not be further partitioned into a binary tree because its size exceeds MaxBTSize (64×64 in this example). Otherwise, the quadtree leaf node will be further partitioned into a binary tree. Therefore, the quadtree leaf node is also the root node of the binary tree, and the depth of the binary tree is 0. When the depth of the binary tree reaches MaxBTDepth (4 in this example), further partitioning is not allowed. A binary tree node with a width equal to MinBTSize (4 in this example) means that no further vertical splits (i.e., split widths) are allowed for that binary tree node. Similarly, a binary tree node with a height equal to MinBTSize means that no further horizontal splits (i.e., split heights) are allowed for that binary tree node. As mentioned above, the leaf nodes of the binary tree are referred to as CUs, and they are further processed according to the prediction and transformation without further splits.

[0081] As described above, the video encoder 200 and video decoder 300 can be configured to decode video data blocks in a merging mode, which is a mode used to signal inter-frame predicted motion information. In some example video codecs (e.g., HEVC and VVC), the merging candidate list construction process may introduce dependencies between adjacent blocks due to the use of spatial merging candidates. In some example video encoder implementations, the motion estimation phase of adjacent blocks is typically performed in parallel or at least in a pipelined manner (e.g., by...). Figure 3 The motion estimation unit 222 performs motion estimation to increase processing power. Due to the dependencies between adjacent blocks, the candidate list for merging adjacent blocks cannot be generated in parallel and can represent a bottleneck in parallel encoder / decoder designs.

[0082] Therefore, a parallel merge estimation process is introduced in HEVC. The parallel merge estimation process in HEVC uses an indication of a region (e.g., MER) in which the video encoder 200 and video decoder 300 can simultaneously derive merge candidate lists for two or more blocks. The video encoder 200 and video decoder 300 can derive merge candidate lists for all blocks within the MER in parallel. In some examples, the MER may include a single block. That is, the video encoder 200 (e.g., via motion estimation unit 222 and motion compensation unit 224) and video decoder 300 (e.g., via motion compensation unit 316) can perform the merge candidate list construction process in parallel for multiple blocks within the indicated region (e.g., MER).

[0083] The video encoder 200 and video decoder 300 determine which block to construct the parallel merge candidate list for by checking whether the candidate block is within the indicated MER. Candidate blocks in the same MER as the current block are not included in the merge candidate list. Therefore, motion data for the candidate is not required during merge candidate list construction.

[0084] In the example of a MER of size 32×32 samples, the video encoder 200 and the video decoder 300 can be configured to construct a merge candidate list in parallel for all blocks (e.g., decoding units or prediction units) in the 32×32 sample region, since all merge candidates within the same 32×32 MER are not added to the merge candidate list. Figure 3 An example of dividing the CTU150 into seven CUs and ten PUs is shown. The first CU includes PU0 and PU1, the second CU includes PU2, the third CU includes PU3, the fourth CU includes PU4, the fifth CU includes PU5 and PU6, the sixth CU includes PU7, and the seventh CU includes PU8 and PU9. Figure 3In this context, the CTU 150 includes a 64×64 luminance decoding tree block. Motion estimation is performed independently for each PU (dashed box) within a 32×32 MER 152, enabling parallel motion estimation (e.g., including candidate list construction) for each PU within a MER 152. For illustrative purposes, Figure 3 Possible spatial merging candidates for PU0, PU5, and PU9 are shown.

[0085] exist Figure 3 In the example, merge candidate 154 for PU0 is available in the merge candidate list because those merge candidates are outside the 32×32 MER that includes PU0. For a 32×32 MER that includes PU2-PU6, the merge candidate list for PU2-PU6 cannot include motion data from any of PU2-PU6 because the merge estimation and merge candidate list construction within that MER should be independent (e.g., will be performed in parallel). Therefore, referring to PU5, merge candidate 156 is unavailable because it is in the same MER that includes PU5. Merge candidate 158 for PU5 is unavailable because the candidate position has not yet been decoded. Therefore, the merge list for PU5 can include only time candidates (if available) and zero MV candidates. For PU9, merge candidate 154 is available because those merge candidates are outside the MER that includes PU9. Merge candidate 156 is unavailable because it is in the same MER as PU9, and merge candidate 158 is unavailable because the candidate positions have not yet been decoded.

[0086] To enable the encoder (e.g., video encoder 200) to balance parallelism and decoding efficiency, the parallel merge estimation level (e.g., the size of the MER) can be adaptive and signaled using syntax elements. For example, video encoder 200 can signal syntax elements (e.g., log2_parallel_merge_level_minus2) indicating the size of the MER in the Picture Parameter Set (PPS). The following MER sizes are allowed in HEVC: 4×4 (parallel merge list construction is not possible), 8×8, 16×16, 32×32, and 64×64. Higher levels of parallelization achieved by larger MERs exclude more potential candidates from the merge candidate list. However, larger MERs may reduce decoding efficiency.

[0087] The HMVP in VVC Draft 7 prevents parallelization derived from the merge candidate list. HMVP merge candidates are added to the merge list after the spatial MVP and TMVP. In the HMVP implemented as in VVC Draft 7, motion information of previously decoded blocks is stored in a table and used as the MVP of the current CU. A table with multiple HMVP candidates is maintained during the encoding / decoding process. When a new CTU row is encountered, the table is reset (cleared). Whenever a non-subblock is inter-decoded by a CU, the associated motion information is added to the last entry of the table as a new HMVP candidate. However, for blocks decoded in parallel within the MER, the motion information of previously decoded blocks may be unknown, potentially preventing the use of HMVP or reducing the parallelism of the MER implementation.

[0088] This disclosure describes a process for restricting the addition of HMVP candidates to the HMVP table when using MER, so that HMVP and MER can be used in combination. According to one technique of this disclosure, updates to the HMVP table are restricted such that the associated motion information of the current block is added as the last entry of the HMVP table as a new HMVP candidate if and only if one of the following is true: (1) the size of the current block is greater than or equal to the size of the MER, or (2) the current block is located at the lower right corner of the current MER. Return to Reference Figure 3 PU1, PU6, PU7, and PU9 are examples of blocks located at the bottom right of MER.

[0089] For example, if the first condition is implemented, the video encoder 200 and the video decoder 300 can be configured to store a table of HMVP; determine motion information of a first block of video data; add the motion information of the first block to the HMVP table in response to determining that the first block is greater than or equal to the size of the MER; and use the HMVP table to decode a second block of video data. If the second condition is implemented, the video encoder 200 and the video decoder 300 can be configured to store a table of HMVP; determine motion information of a first block of video data; add the motion information of the first block to the HMVP table in response to determining that the first block is located at the lower right corner of the MER; and use the HMVP table to decode a second block of video data.

[0090] In some examples, the associated motion information of the current block is added to the last entry of the table as a new HMVP candidate only if one of the following is true:

[0091] 1)cbWidth>=merSize and cbHeight>=merSize

[0092] 2) floor(xCb / merSize) < floor((xCb + cbWidth) / merSize) and floor(yCb / merSize) < floor((yCb + cbHeight) / merSize)

[0093] Here, xCb and yCb are the coordinates of the top - left sample in the current block, cbWidth and cbHeight are the width and height of the current block, and merSize is the size of the MER. Floor(x) is an operator that obtains the largest integer value less than or equal to x. For example, video encoder 200 and video decoder 300 may be configured to determine whether the value of the x - coordinate of the top - left sample of the first block plus the value of the width of the first block divided by the size of the MER is greater than the value of the x - coordinate of the top - left sample divided by the size of the MER, and determine whether the value of the y - coordinate of the top - left sample of the first block plus the value of the height of the first block divided by the size of the MER is greater than the value of the y - coordinate of the top - left sample divided by the size of the MER. Video encoder 200 and video decoder 300 may be configured to add the motion information of the first block to the table of HMVP in response to determining that the value of the x - coordinate of the top - left sample of the first block plus the value of the width of the first block divided by the size of the MER is greater than the value of the x - coordinate of the top - left sample divided by the size of the MER, and in response to determining that the value of the y - coordinate of the top - left sample of the first block plus the value of the height of the first block divided by the size of the MER is greater than the value of the y - coordinate of the top - left sample divided by the size of the MER.

[0094] In another example, the associated motion information of the current block is added to the last entry of the table as a new HMVP candidate if and only if one of the following is true:

[0095] 1) cbWidth >= merSize and cbHeight >= merSize

[0096] 2) floor(xCb / merSize)+1 == floor((xCb + cbWidth) / merSize) and floor(yCb / merSize)+1 ==

[0097] floor((yCb + cbHeight) / merSize).

[0098] In some examples of the present disclosure, a second HMVP table may be maintained. When decoding the current block within the MER, the second table is used instead of the original table. And the second HMVP table is not updated with the associated motion information of the current block. The original HMVP table is updated with the associated motion information of the current block. When decoding the current block that includes one or more MERs, the original table is used.

[0099] In some examples, a second HMVP table is maintained. When decoding the current block within the MER, the second table is used instead of the original table. The associated motion information of the current block is not used to update the second HMVP table. The original HMVP table is updated using the associated motion information of a limited number of blocks located at specific positions within the MER. In some examples, if the current block is located in the bottom right corner of the current MER, the original HMVP table is updated using the associated motion information of the current block. In some examples, if the current block is located in the center of the current MER, the original HMVP table is updated using the associated motion information of the current block. In some examples, if the current block is located in the top left corner of the current MER, the original HMVP table is updated using the associated motion information of the current block.

[0100] Figure 4 This is a block diagram illustrating an example video encoder 200 capable of performing the techniques described herein. Figure 4 This disclosure is for illustrative purposes and should not be construed as limiting the techniques extensively illustrated and described herein. For illustrative purposes, this disclosure describes a video encoder 200 based on JEM, VVC (ITU-T H.266, under development), and HEVC (ITU-T H.265) technologies. However, the techniques of this disclosure can be implemented by video encoding devices configured for other video decoding standards.

[0101] exist Figure 4 In the example, 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 one or all of the video data memory 230, mode selection unit 202, residual generation unit 204, transform processing unit 206, quantization unit 208, inverse quantization unit 210, inverse transform processing unit, reconstruction unit 214, filter unit 216, DPB 218, and entropy coding unit 220 can be implemented in one or more processors or processing circuits. For example, the units of the video encoder 200 can be implemented as part of hardware circuitry or as part of a processor, ASIC, or FPGA, or as one or more circuit or logic elements. Furthermore, the video encoder 200 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0102] The video data storage device 230 can store video data encoded by components of the video encoder 200. The video encoder 200 can retrieve data from, for example, a video source 104 (…). Figure 1The video encoder 200 receives video data stored in video data memory 230. DPB 218 can be used as a reference picture memory, storing reference video data for use by the video encoder 200 when predicting subsequent video data. Video data memory 230 and DPB 218 can be formed from any of a variety of storage devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of storage devices. Video data memory 230 and DPB 218 can be provided by the same storage device or separate storage devices. In various examples, video data memory 230 can be on-chip with other components of the video encoder 200, as shown, or off-chip relative to those components.

[0103] In this disclosure, references to video data memory 230 should not be construed as being limited to memory internal to video encoder 200 unless so specifically described, or memory external to video encoder 200 unless so specifically described. Rather, references to video data memory 230 should be understood as a reference memory storing video data received by video encoder 200 for encoding (e.g., video data of the current block to be encoded). Figure 1 The memory 106 can also provide temporary storage for the outputs of the various units of the video encoder 200.

[0104] Show Figure 4 The various units help to understand the operations performed by the video encoder 200. These units can be implemented as fixed-function circuits, programmable circuits, or a combination thereof. A fixed-function circuit is a circuit that provides a specific function and is pre-programmed to perform certain operations. A programmable circuit is a circuit that can be programmed to perform various tasks and provides flexible functionality in the operations it can perform. For example, a programmable circuit can execute software or firmware that causes it to operate in a manner defined by software or firmware instructions. A fixed-function circuit can execute software instructions (e.g., to receive or output parameters), but the type of operation performed by a fixed-function circuit is typically immutable. In some examples, one or more units may be different circuit blocks (fixed-function or programmable), and in some examples, one or more units may be integrated circuits.

[0105] The video encoder 200 may include an arithmetic logic unit (ALU), an essential function unit (EFU), digital circuitry, analog circuitry, and / or a programmable core, all formed by programmable circuitry. In an example where the operation of the video encoder 200 is performed using software executed by programmable circuitry, memory 106 ( Figure 1The video encoder 200 may store instructions (e.g., object code) of the software received and executed by the video encoder 200, or such instructions may be stored in another memory (not shown) within the video encoder 200.

[0106] The video data storage unit 230 is configured to store received video data. The video encoder 200 can extract images of the video data from the video data storage unit 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 storage unit 230 can be the raw video data to be encoded.

[0107] The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra-frame prediction unit 226. The mode selection unit 202 may include other functional units to perform video prediction based on other prediction modes. As an example, the mode selection unit 202 may include a palette unit, an intra-block copying 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.

[0108] Mode selection unit 202 typically coordinates multiple encoding operations to test combinations of encoding parameters and the resulting rate distortion values ​​for such combinations. Encoding parameters may include dividing the CTU into CUs, the prediction mode for the CUs, the transformation type for the residual data of the CUs, the quantization parameters for the residual data of the CUs, and so on. Mode selection unit 202 can ultimately select a combination of encoding parameters that yields a rate distortion value superior to other tested combinations.

[0109] The video encoder 200 can divide the images extracted from the video data storage 230 into a series of CTUs and encapsulate one or more CTUs within a segment. The mode selection unit 202 can divide the image into CTUs according to a tree structure, such as the QTBT structure or quadtree structure of HEVC described above. As mentioned above, the video encoder 200 can form one or more CUs by dividing CTUs according to a tree structure. Such CUs are usually referred to as "video blocks" or "blocks".

[0110] Typically, mode selection unit 202 also controls its components (e.g., motion estimation unit 222, motion compensation unit 224, and intra-prediction unit 226) to generate prediction blocks for the current block (e.g., the current CU, or the overlapping portion of PU and TU in HEVC). To perform inter-frame prediction for the current block, motion estimation unit 222 may perform a motion search to identify one or more closely matching reference blocks in one or more reference pictures (e.g., one or more previously encoded pictures stored in DPB 218). Specifically, motion estimation unit 222 may calculate values ​​representing the similarity between the potential reference block and the current block, for example, based on sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared error (MSD), etc. Motion estimation unit 222 may typically perform these calculations using sample-by-sample differences between the current block and the considered reference blocks. Motion estimation unit 222 may identify reference blocks with the lowest values ​​produced by these calculations, indicating the reference block that most closely matches the current block.

[0111] Motion estimation unit 222 can generate one or more motion vectors (MVs) that define the position of a reference block in a reference image relative to the position of a current block in the current image. Motion estimation unit 222 can then provide the motion vectors to motion compensation unit 224. For example, for unidirectional inter-frame prediction, motion estimation unit 222 can provide a single motion vector, while for bidirectional inter-frame prediction, motion estimation unit 222 can provide two motion vectors. Motion compensation unit 224 can then use the motion vectors to generate prediction blocks. For example, motion compensation unit 224 can use the motion vectors to extract data from the reference blocks. As another example, if the motion vectors have fractional-sample precision, motion compensation unit 224 can interpolate the values ​​of the prediction blocks according to one or more interpolation filters. Furthermore, for bidirectional inter-frame prediction, motion compensation unit 224 can extract data from the two reference blocks identified by the corresponding motion vectors, for example, by per-sample averaging or weighted averaging, and combine the extracted data. Motion estimation unit 222 and motion compensation unit 224 can be configured to use MER to decode the blocks as described above.

[0112] As another example, for intra-prediction or intra-prediction decoding, intra-prediction unit 226 can generate a prediction block based on samples adjacent to the current block. For example, in directional mode, intra-prediction unit 226 can typically mathematically combine the values ​​of adjacent samples and fill these calculated values ​​across the current block in a defined direction to generate a prediction block. As another example, in DC mode, intra-prediction unit 226 can calculate the average of the adjacent samples of the current block and generate a prediction block such that each sample in the prediction block includes the obtained average.

[0113] Mode selection unit 202 provides the prediction block to residual generation unit 204. Residual generation unit 204 receives the original uncoded version of the current block from video data memory 230 and the prediction block from mode selection unit 202. Residual generation unit 204 calculates the sample-by-sample difference between the current block and the prediction block. The resulting sample-by-sample difference defines the residual block for the current block. In some examples, residual generation unit 204 may also determine the difference between sample values ​​in the residual block to generate the residual block using residual differential pulse code modulation (RDPCM). In some examples, one or more subtractor circuits performing binary subtraction may be used to form residual generation unit 204.

[0114] In the example where mode selection unit 202 divides a CU into PUs, each PU can be associated with a luma prediction unit and a corresponding chroma prediction unit. Video encoder 200 and video decoder 300 can support PUs of various sizes. As mentioned above, the size of a CU can refer to the size of its luma coding block, and the size of a PU can refer to the size of the luma prediction unit within that PU. Assuming a specific CU size is 2N×2N, video encoder 200 can support PU sizes of 2N×2N or N×N for intra-frame prediction, and symmetrical PU sizes of 2N×2N, 2N×N, N×2N, N×N, or similar sizes for inter-frame prediction. Video encoder 200 and video decoder 300 can also support asymmetric partitioning of PU sizes of 2N×nU, 2N×nD, nL×2N, and nR×2N for inter-frame prediction.

[0115] In the example where mode selection unit 202 does not further divide the CU into PUs, each CU can be associated with a luma coding block and a corresponding chroma coding block. As mentioned above, the size of the CU can refer to the size of the luma coding block of the CU. The video encoder 200 and the video decoder 300 can support CU sizes of 2N×2N, 2N×N, or N×2N.

[0116] For other video decoding techniques (such as intra-block copy mode decoding, affine mode decoding, and linear model (LM) mode decoding, as a few examples), mode selection unit 202 generates a prediction block for the current block being encoded via a corresponding unit associated with the decoding technique. In some examples, such as palette mode decoding, mode selection unit 202 may not generate a prediction block, but instead generate syntax elements that indicate how the block should be reconstructed based on the selected palette. In such modes, mode selection unit 202 can provide these syntax elements to entropy coding unit 220 for encoding.

[0117] As described above, the residual generation unit 204 receives video data of the current block and the corresponding prediction 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 prediction block and the current block.

[0118] Transform processing unit 206 applies one or more transformations 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 transformations to the residual block to form the transform coefficient block. For example, transform processing unit 206 may apply a Discrete Cosine Transform (DCT), direction transformation, Karhunen-Loeve Transform (KLT), or a conceptually similar transformation to the residual block. In some examples, transform processing unit 206 may perform multiple transformations on the residual block, such as first-order and second-order transformations, such as rotation transformations. In some examples, transform processing unit 206 does not apply any transformations to the residual block.

[0119] Quantization unit 208 can quantize the transform coefficients in a transform coefficient block to produce a quantized transform coefficient block. Quantization unit 208 can quantize the transform coefficients of the transform coefficient block based on the quantization parameter (QP) value associated with the current block. Video encoder 200 (e.g., via mode selection unit 202) can 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 introduce information loss; therefore, the quantized transform coefficients may have lower precision than the original transform coefficients generated by transform processing unit 206.

[0120] The inverse quantization unit 210 and the inverse transform processing unit 212 can apply inverse quantization and inverse transform to the quantized transform coefficient block, respectively, to reconstruct the residual block from the transform coefficient block. The reconstruction unit 214 can generate a reconstructed block corresponding to the current block based on the reconstructed residual block and the prediction block generated by the mode selection unit 202 (although it may have some degree of distortion). For example, the reconstruction unit 214 can add samples of the reconstructed residual block to corresponding samples of the prediction block generated by the mode selection unit 202 to generate the reconstructed block.

[0121] Filter unit 216 can perform one or more filter operations on the reconstructed block. For example, filter unit 216 can perform a deblocking operation to reduce blocky artifacts along the edges of the CU. In some examples, the operations of filter unit 216 can be skipped.

[0122] The video encoder 200 stores reconstructed blocks in the DPB 218. For example, in an example where the operation of the filter unit 216 is not required, the reconstruction unit 214 can store the reconstructed blocks in the DPB 218. In an example where the operation of the filter unit 216 is required, the filter unit 216 can store filtered reconstructed blocks in the DPB 218. The motion estimation unit 222 and the motion compensation unit 224 can extract reference images from the DPB 218, which are formed from the reconstructed (and possibly filtered) blocks, to perform inter-frame prediction of blocks in subsequent encoded images. Additionally, the intra-frame prediction unit 226 can use the reconstructed blocks in the DPB 218 of the current image to perform intra-frame prediction of other blocks in the current image.

[0123] Typically, entropy coding unit 220 can entropy-encode syntax elements received from other functional components of video encoder 200. For example, entropy coding unit 220 can entropy-encode quantized transform coefficient blocks from quantization unit 208. As another example, entropy coding unit 220 can entropy-encode predictive syntax elements (e.g., motion information for inter-frame prediction or intra-frame mode information for intra-frame prediction) from mode selection unit 202. Entropy coding unit 220 can perform one or more entropy coding operations on syntax elements (which are another example of video data) to generate entropy-encoded data. For example, entropy coding unit 220 can perform context-adaptive variable-length coding (CAVLC), CABAC, variable-to-variable (V2V) length coding, syntax-based context-adaptive binary arithmetic coding (SBAC), probabilistic interval segmented entropy (PIPE) coding, exponential Golomb coding, or another entropy coding operation on the data. In some examples, entropy coding unit 220 can operate in a bypass mode where no entropy coding is performed on syntax elements.

[0124] The video encoder 200 can output a bitstream containing the entropy-coded syntax elements required to reconstruct segments or images. Specifically, the entropy coding unit 220 can output a bitstream.

[0125] The above operations are described in relation to the blocks. Such a description should be understood as referring to operations on the luma decoding block and / or chroma decoding block. As mentioned above, in some examples, the luma decoding block and chroma decoding block are the luma and chroma components of the CU. In some examples, the luma decoding block and chroma decoding block are the luma and chroma components of the PU.

[0126] In some examples, it is not necessary to repeat the operations performed for the luma-coded block for the chroma-coded block. As an example, it is not necessary to repeat the operations used to identify the MV and reference image for the luma-coded block in order to identify the motion vector (MV) and reference image for the chroma-coded block. Instead, the MV for the luma-coded block can be scaled to determine the MV for the chroma-coded block, and the reference image can be the same. As another example, the intra-frame prediction processing can be the same for both the luma-coded block and the chroma-coded block.

[0127] Video encoder 200 represents an example 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 the techniques of this disclosure. For example, mode selection unit 202 (e.g., motion estimation unit 222 and / or motion compensation unit 224) may store a table of HMVPs, which will be used when constructing a merge candidate list for blocks decoded in merge mode. Mode selection unit 202 may determine motion information for a first block of video data, add the motion information of the first block to the HMVP table in response to determining that the first block is located at the lower right corner of the MER, and use the HMVP table to decode a second block of video data. Mode selection unit 202 may, for example, use entries from the HMVP table to generate a merge candidate list for the second block.

[0128] Figure 5 This is a block diagram illustrating an example video decoder 300 capable of performing the techniques described herein. Figure 5 This disclosure is for illustrative purposes and should not be construed as limiting the techniques extensively illustrated and described herein. For illustrative purposes, this disclosure describes a video decoder 300 based on JEM, VVC (ITU-T H.266, under development), and HEVC (ITU-T H.265) technologies. However, the techniques of this disclosure can be implemented by video decoding devices configured for other video decoding standards.

[0129] exist Figure 5In the example, the video decoder 300 includes an encoded 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 one or all of the CPB memory 320, entropy decoding unit 302, prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, filter unit 312, and DPB 314 can be implemented in one or more processors or processing circuitry. For example, units of the video decoder 300 can be implemented as part of hardware circuitry or as part of a processor, ASIC, or FPGA, or as one or more circuit or logic elements. Furthermore, the video decoder 300 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0130] The prediction processing unit 304 includes a motion compensation unit 316 and an intra-frame prediction unit 318. The prediction processing unit 304 may include additional units to perform predictions based on other prediction modes. As an example, the prediction processing unit 304 may include a palette unit, an intra-block copy unit (which may form part of the motion compensation unit 316), an affine unit, a linear model (LM) unit, etc. In other examples, the video decoder 300 may include more, fewer, or different functional components.

[0131] CPB memory 320 can store video data, such as encoded video bitstreams, that will be decoded by components of video decoder 300. For example, it can be stored from computer-readable medium 110 ( Figure 1 The video data stored in the CPB memory 320 is obtained. The CPB memory 320 may include a CPB that stores encoded video data (e.g., syntax elements) from the encoded video bitstream. Furthermore, the CPB memory 320 may store video data other than the syntax elements of the encoded picture, such as temporary data representing the output from various units of the video decoder 300. The DPB 314 typically stores decoded pictures, which the video decoder 300 may use as reference video data when outputting and / or decoding subsequent data or pictures of the encoded video bitstream. The CPB memory 320 and the DPB 314 may be formed from any of a variety of storage devices, such as DRAM, including SDRAM, MRAM, RRAM, or other types of storage devices. The CPB memory 320 and the DPB 314 may be provided by the same storage device or separate storage devices. In various examples, the CPB memory 320 may be on-chip with other components of the video decoder 300, or off-chip relative to those components.

[0132] Alternatively, in some examples, the video decoder 300 can be derived from the memory 120 ( Figure 1 Extract encoded video data. That is, memory 120 can store data together with CPB memory 320 as described above. Similarly, when some or all of the functions of video decoder 300 are implemented in software to be executed by the processing circuitry of video decoder 300, memory 120 can store instructions to be executed by video decoder 300.

[0133] Show Figure 5 The various units shown aid in understanding the operations performed by the video decoder 300. These units can be implemented as fixed-function circuits, programmable circuits, or a combination thereof. Similar to... Figure 4 Fixed-function circuits are circuits that provide a specific function and are pre-programmed to perform certain operations. Programmable circuits are circuits that can be programmed to perform various tasks and provide flexible functionality in the operations they can perform. For example, a programmable circuit can execute software or firmware that causes it to operate in a manner defined by software or firmware instructions. Fixed-function circuits can execute software instructions (e.g., to receive or output parameters), but the type of operation performed by a fixed-function circuit is typically immutable. In some examples, one or more units may be different circuit blocks (fixed-function or programmable), and in some examples, one or more units may be integrated circuits.

[0134] The video decoder 300 may include an ALU, EFU, digital circuitry, analog circuitry, and / or a programmable core formed by programmable circuitry. In an example where the operation of the video decoder 300 is performed by software executed on the programmable circuitry, on-chip or off-chip memory may store instructions (e.g., object code) of the software received and executed by the video decoder 300.

[0135] Entropy decoding unit 302 can receive encoded video data from the CPB and perform entropy decoding on the video data to reproduce the syntax elements. Prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, and filter unit 312 can generate decoded video data based on the syntax elements extracted from the bitstream.

[0136] Typically, the video decoder 300 reconstructs the image on a block-by-block basis. The video decoder 300 can perform the reconstruction operation on each block individually (where the block currently being reconstructed (i.e., decoded) can be referred to as the "current block").

[0137] Entropy decoding unit 302 can entropy decode the syntax elements of the quantized transform coefficients defining the quantized transform coefficient block, as well as transform information such as quantization parameters (QP) and / or transform mode indications. Inverse quantization unit 306 can use the QP associated with the quantized transform coefficient block to determine the quantization degree, and similarly, determine the inverse quantization degree for application by inverse quantization unit 306. Inverse quantization unit 306 can, for example, perform a bitwise left shift operation to inverse quantize the quantized transform coefficients. Inverse quantization unit 306 can thereby form a transform coefficient block including the transform coefficients.

[0138] After the inverse quantization unit 306 forms the transform coefficient block, the inverse transform processing unit 308 can 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 can apply the inverse DCT, inverse integer transform, inverse Karhunen-Loeve transform (KLT), inverse rotation transform, inverse direction transform, or another inverse transform to the transform coefficient block.

[0139] Furthermore, prediction processing unit 304 generates prediction blocks based on prediction information syntax elements entropy decoded by entropy decoding unit 302. For example, if the prediction information syntax elements indicate that the current block is inter-frame predicted, motion compensation unit 316 can generate prediction blocks. In this case, the prediction information syntax elements may indicate a reference image from which the reference block is extracted in DPB 314, and a motion vector that identifies the position of the reference block in the reference image relative to the current block in the current image. Motion compensation unit 316 can typically be configured with respect to motion compensation unit 224 ( Figure 4 Inter-frame prediction processing is performed in a manner substantially similar to that described above. The motion compensation unit 316 can be configured to use MER to decode blocks as described above.

[0140] As another example, if the prediction information syntax element indicates that the current block is intra-predictive, then intra-predictive unit 318 can generate a prediction block according to the intra-predictive mode indicated by the prediction information syntax element. Similarly, intra-predictive unit 318 can typically be configured with respect to intra-predictive unit 226 ( Figure 4 Intra-prediction processing is performed in a manner substantially similar to that described above. Intra-prediction unit 318 can extract data from neighboring samples of the current block from DPB 314.

[0141] Reconstruction unit 310 can use the prediction block and the residual block to reconstruct the current block. For example, reconstruction unit 310 can add samples from the residual block to the corresponding samples from the prediction block to reconstruct the current block.

[0142] Filter unit 312 can perform one or more filter operations on the reconstructed block. For example, filter unit 312 can perform a deblocking operation to reduce blocky artifacts along the edges of the reconstructed block. The operation of filter unit 312 is not necessarily performed in all examples.

[0143] The video decoder 300 can store reconstructed blocks in the DPB 314. For example, in an example where the filter unit 312 is not operating, the reconstruction unit 310 can store reconstructed blocks in the DPB 314. In an example where the filter unit 312 is operating, the filter unit 312 can store filtered reconstructed blocks in the DPB 314. As described above, the DPB 314 can provide reference information to the prediction processing unit 304, such as samples of the current image for intra-frame prediction and previously decoded images for subsequent motion compensation. Furthermore, the video decoder 300 can output decoded images (e.g., decoded video) from the DPB 314 for subsequent display on a display device (e.g., [unclear text - possibly a device name]). Figure 1 It is displayed on the display device 118.

[0144] Video decoder 300 represents an example of a video decoding device, including a memory configured to store video data; and one or more processing units implemented in circuitry and configured to perform the techniques of this disclosure. For example, prediction processing unit 304 (e.g., motion compensation unit 316) may store a table of HMVPs, which will be used when constructing a merge candidate list for blocks decoded in merge mode. Prediction processing unit 304 may determine motion information for a first block of video data, add the motion information of the first block to the HMVP table in response to determining that the first block is located at the lower right corner of the MER, and use the HMVP table to decode a second block of video data. Prediction processing unit 304 may, for example, use entries from the HMVP table to generate a merge candidate list for the second block.

[0145] Figure 6 This is a flowchart illustrating an example process for encoding the current block. The current block may include the current CU. Although regarding video encoder 200 ( Figure 1 and 4 The description is provided, but it should be understood that other devices can be configured to perform the same actions. Figure 6 A similar process.

[0146] In this example, the video encoder 200 initially predicts the current block (350). As part of the predicted block, the video encoder 200 may maintain one or more HMVP tables as disclosed herein and may update those tables according to the techniques described herein. For example, the video encoder 200 may form a predicted block for the current block. The video encoder 200 may then compute a residual block for the current block (352). To compute the residual block, the video encoder 200 may compute the difference between the original uncoded block and the predicted block for the current block. The video encoder 200 may then transform the residual block and quantize the transform coefficients of the residual block (354). Next, the video encoder 200 may scan the quantized transform coefficients of the residual block (356). During or after the scan, the video encoder 200 may entropy-encode the transform coefficients (358). For example, the video encoder 200 may use CAVLC or CABAC to encode the transform coefficients. The video encoder 200 may then output the entropy-encoded data of the block (360).

[0147] Figure 7 This is a flowchart illustrating an example process for decoding the current block of video data. The current block may include the current CU. Although regarding video decoder 300 ( Figure 1 and Figure 5 The description is provided, but it should be understood that other devices can be configured to perform the same actions. Figure 7 A similar process.

[0148] The video decoder 300 may receive entropy-coded data of the current block, such as entropy-coded prediction information and entropy-coded data corresponding to the coefficients of the residual block of the current block (370). The video decoder 300 may entropy-decode the entropy-coded data to determine the prediction information of the current block and reproduce the coefficients of the residual block (372). The video decoder 300 may, for example, use an intra-frame or inter-frame prediction mode indicated by the prediction information of the current block to predict the current block (374) to compute the prediction block of the current block. As part of the prediction block, the video decoder 300 may maintain one or more HMVP tables as disclosed herein and may update those tables according to the techniques described herein. The video decoder 300 may then perform an inverse scan on the reproduced coefficients (376) to produce a quantized transform coefficient block. The video decoder 300 may then perform inverse quantization and inverse transform on the transform coefficients to produce a residual block (378). The video decoder 300 may finally decode the current block by combining the prediction block and the residual block (380).

[0149] Figure 8 This is a flowchart illustrating an example process for decoding the current block of video data. The current block may include the current CU. The description will be in relation to a general video decoder. Figure 8 The technology, the general video decoder may, for example, correspond to video decoder 300 ( Figure 1 and Figure 5), Video decoder loop of video encoder 200 ( Figure 1 and Figure 4 (or any other such video decoder.)

[0150] The video decoder stores a table of HMVP (400). The video decoder may, for example, maintain the HMVP table and, when decoding a new block, add motion information for decoding the new block to the HMVP table. The decoder may also periodically remove entries from the HMVP table to limit the table size. The video decoder determines motion information for the first block of video data (402). The video decoder may, for example, use the determined motion information to predict the first block inter-frame.

[0151] The video decoder adds the motion information of the first block to the HMVP table (404) in response to determining that the first block is located at the bottom right corner of the MER. The MER can be the first MER, and the second block can belong to the second MER. In order to add the motion information of the first block to the HMVP table in response to determining that the first block is located at the bottom right corner of the MER, the video decoder can, for example, determine whether the x-coordinate value of the top left sample of the first block plus the width of the first block divided by the size of the MER is greater than the x-coordinate value of the top left sample divided by the size of the MER, and determine whether the y-coordinate value of the top left sample of the first block plus the height of the first block divided by the size of the MER is greater than the y-coordinate value of the top left sample divided by the size of the MER. In response to determining that the x-coordinate value of the top left sample of the first block plus the width of the first block divided by the size of the MER is greater than the x-coordinate value of the top left sample divided by the size of the MER, and in response to determining that the y-coordinate value of the top left sample of the first block plus the height of the first block divided by the size of the MER is greater than the y-coordinate value of the top left sample divided by the size of the MER, the video decoder can add the motion information of the first block to the HMVP table.

[0152] The video decoder uses an HMVP table to decode the second block of video data (406). To use the HMVP table to decode the second block of video data, the video decoder can, for example, be configured to generate a candidate list of motion information for the second block, the candidate list including candidates from the HMVP table; select a candidate from the candidate list of motion vectors; and use the selected candidate to decode the second block of video data. The video decoder can, for example, output a decoded version of the video data including the first and second blocks. In an implementation where the video decoder is operating to perform a video encoding process, the video decoder can store one or more decoded images including the decoded versions of the first and second blocks, and use one or more of the stored decoded images to encode other blocks of other images of the video data.

[0153] The following clauses represent exemplary implementations of the technologies and devices described above.

[0154] Clause 1: A method for decoding video data, comprising: storing a table of historical motion vector predictors (HMVP); determining motion information of a current block of video data; and updating the table of historical motion vector predictors based on the determined motion information of the current block according to any technique or combination of techniques described in this disclosure.

[0155] Clause 2: According to the method of Clause 1, wherein updating the HMVP table based on the determined motion information of the current block includes: adding the motion information of the current block to the HMVP table in response to determining that the current block is greater than or equal to the size of the motion estimation region.

[0156] Clause 3: According to the method of Clause 1, wherein updating the HMVP table based on the determined motion information of the current block includes: adding the motion information of the current block to the HMVP table in response to determining that the current block is located in the lower right corner of the motion estimation region.

[0157] Clause 4: The method according to any one of Clauses 1 to 3 further includes, for a second current block being decoded after the current block, generating a candidate list for the second current block by adding candidates from the table of HMVP to the candidate list.

[0158] Clause 5: A method for decoding video data, comprising: storing a table of first history-based motion vector prediction factors (HMVP); storing a table of second HMVP; determining motion information of a current block of video data; and updating the table of first HMVP and / or the table of second HMVP based on the determined motion information of the current block, according to any technique or combination of techniques described in this disclosure.

[0159] Clause 6: The method of Clause 5 further includes, for a second current block being decoded after the current block, generating a candidate list for the second current block by adding candidates from the table of the first HMVP or the table of the second HMVP to the candidate list.

[0160] Clause 7: The method according to any one of Clauses 1 to 6, wherein decoding includes decoding.

[0161] Clause 8: The method according to any one of Clauses 1 to 6, wherein decoding includes encoding.

[0162] Clause 9: An apparatus for decoding video data, the apparatus comprising one or more modules for performing a method pursuant to any one of Clauses 1 to 8.

[0163] Clause 10: A device pursuant to Clause 9, wherein one or more modules include one or more processors implemented in a circuit.

[0164] Clause 11: The device pursuant to any one of Clauses 9 and 10 also includes a memory for storing video data.

[0165] Clause 12: The device pursuant to any one of Clauses 9-11 also includes a display configured to display decoded video data.

[0166] Clause 13: Equipment under any one of Clauses 9-12, wherein the equipment includes one or more of a camera, computer, mobile device, broadcast receiver equipment or set-top box.

[0167] Clause 14: Device pursuant to any one of Clauses 9-13, wherein the device includes a video decoder.

[0168] Clause 15: Devices pursuant to any one of Clauses 9-14, wherein the device includes a video encoder.

[0169] Clause 16: A computer-readable storage medium having instructions stored thereon, which, when executed, cause one or more processors to perform a method according to any one of Clauses 1 to 8.

[0170] It should be recognized that, based on the examples, certain operations or events of any technique described herein may be performed in a different order, and may be added, combined, or omitted entirely (e.g., not all described operations or events are necessary for implementing the technique). Furthermore, in some examples, operations or events may be performed concurrently rather than sequentially, for example, through multithreading, interrupt handling, or multiple processors.

[0171] In one or more exemplary designs, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored or transmitted as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium includes a computer storage medium, which corresponds to a tangible medium such as a data storage medium, or a communication medium, including, for example, any medium that facilitates the transfer of a computer program from one place to another according to a communication protocol. In this way, a computer-readable medium may generally correspond to (1) a non-transitory tangible computer-readable storage medium, 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 extract instructions, code, and / or data structures to implement the techniques described in this disclosure. Computer program products may include computer-readable media.

[0172] For example, but not limited to, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, flash memory, or any other medium that can be used to store required program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, any connection may be appropriately referred to as a computer-readable medium. For example, if software is 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, wireless, and microwave, then such coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are also included in the definition of medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but rather refer to non-transient tangible storage media. The disks and optical discs used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, wherein disks typically reproduce data magnetically, while optical discs typically reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable media.

[0173] Instructions can be executed by one or more processors, such as one or more DSPs, general-purpose microprocessors, application-specific integrated circuits (ASICs), FPGAs, or other equivalent integrated or discrete logic circuits. Accordingly, the terms "processor" and "processing circuit" as used herein can refer to any of the foregoing structures or any other structures suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein can be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into combined codecs. Similarly, the technique can be fully implemented in one or more circuit or logic elements.

[0174] The technologies disclosed herein can be implemented in various devices or apparatuses, including wireless handheld devices, integrated circuits (ICs), or a set of ICs (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize functional aspects of a device configured to perform the disclosed technologies, but they do not necessarily need to be implemented by different hardware units. Rather, as described above, various units can be combined in a codec hardware unit or provided by a collection of interoperable hardware units, including one or more processors as described above combined with suitable software and / or firmware.

[0175] Various examples have been described. These and other examples are within the scope of the appended claims.

Claims

1. A method for decoding video data, the method comprising: A table storing historical motion vector predictors (HMVP); Determine the motion information of the first block of the video data; In response to determining that the first block is located in the lower right corner of the motion estimation region (MER), the motion information of the first block is added to the table of the HMVP; as well as Use the table in the HMVP to decode the second block of the video data. The process of adding the motion information of the first block to the table of the HMVP in response to determining that the first block is located at the lower right corner of the MER includes: Determine whether floor((xCb + cbWidth) / merSize) is greater than floor(xCb / merSize), where xCb represents the x-coordinate of the top-left sample of the first block, cbWidth represents the width of the first block, merSize represents the size of the MER, and floor() represents the floor function (rounding down). Determine whether floor((yCb + cbHeight) / merSize) is greater than floor(yCb / merSize), where yCb represents the y-coordinate of the top-left sample of the first block, and cbHeight represents the height of the first block; and In response to determining that floor((xCb + cbWidth) / merSize) is greater than floor(xCb / merSize) and in response to determining that floor((yCb + cbHeight) / merSize) is greater than floor(yCb / merSize), the motion information of the first block is added to the table of the HMVP. Wherein, the MER is the first MER, and the second block belongs to the second MER.

2. The method according to claim 1, wherein, The second block of decoding the video data using the HMVP table includes: For the second block, a candidate list of motion information is generated, wherein the candidate list includes candidates from the table of the HMVP; Candidates are selected from the candidate list of motion vectors; and The selected candidate is used to decode the second block of the video data.

3. The method according to claim 1, further comprising: The output includes decoded versions of the first and second blocks of decoded video data.

4. The method according to claim 1, wherein, The method of performing the decoding of video data as part of a video encoding process further includes: Storage includes one or more decoded images comprising decoded versions of the first block and the second block; and Other blocks of other images are encoded using one or more of the stored decoded images to encode the video data.

5. An apparatus for decoding video data, the apparatus comprising: A memory configured to store video data; as well as One or more processors are implemented in a circuit and configured to perform the following operations: A table storing historical motion vector predictors (HMVP); Determine the motion information of the first block of the video data; In response to determining that the first block is located in the lower right corner of the motion estimation region (MER), the motion information of the first block is added to the table of the HMVP; as well as Use the table in the HMVP to decode the second block of the video data. In order to add the motion information of the first block to the table of the HMVP in response to determining that the first block is located at the lower right corner of the MER, the one or more processors are further configured to perform the following operations: Determine whether floor((xCb + cbWidth) / merSize) is greater than floor(xCb / merSize), where xCb represents the x-coordinate of the top-left sample of the first block, cbWidth represents the width of the first block, merSize represents the size of the MER, and floor() represents the floor function (rounding down). Determine whether floor((yCb + cbHeight) / merSize) is greater than floor(yCb / merSize), where yCb represents the y-coordinate of the top-left sample of the first block, and cbHeight represents the height of the first block; and In response to determining that floor((xCb + cbWidth) / merSize) is greater than floor(xCb / merSize) and in response to determining that floor((yCb + cbHeight) / merSize) is greater than floor(yCb / merSize), the motion information of the first block is added to the table of the HMVP. Wherein, the MER is the first MER, and the second block belongs to the second MER.

6. The device according to claim 5, wherein, In order to use the HMVP table to decode the second block of the video data, the one or more processors are further configured to: For the second block, a candidate list of motion information is generated, wherein the candidate list includes candidates from the table of the HMVP; Select a candidate from the candidate list of motion vectors; and The selected candidate is used to decode the second block of the video data.

7. The device according to claim 5, wherein, The one or more processors are also configured to perform the following operations: The output includes decoded versions of the first and second blocks of decoded video data.

8. The device according to claim 5, wherein, The device includes a video encoder, and wherein the one or more processors are further configured to perform the following operations: Storage includes one or more decoded images comprising decoded versions of the first block and the second block; and Other blocks of other images in the video data are encoded using one or more stored decoded images.

9. The device according to claim 5, wherein, The device includes a wireless communication device and a receiver configured to receive encoded video data.

10. The device according to claim 9, wherein, The wireless communication device includes a handset telephone, and wherein the receiver is configured to demodulate a signal including the encoded video data according to a wireless communication standard.

11. The device according to claim 5, further comprising: A display that is configured to display decoded video data.

12. The device according to claim 5, wherein, The device includes one or more of a camera, computer, mobile device, broadcast receiver, or set-top box.

13. The device according to claim 5, wherein, The device includes a wireless communication device and a transmitter configured to transmit encoded video data.

14. The device according to claim 13, wherein, The wireless communication device includes a handset telephone, and wherein the transmitter is configured to modulate a signal including the encoded video data according to a wireless communication standard.

15. The device according to claim 5, further comprising: A camera configured to acquire the video data.

16. A computer-readable storage medium storing instructions, which, when executed by one or more processors, cause the one or more processors to perform the following operations: A table storing historical motion vector predictors (HMVP); Determine the motion information of the first block of video data; In response to determining that the first block is located in the lower right corner of the motion estimation region (MER), the motion information of the first block is added to the table of the HMVP; and Use the table in the HMVP to decode the second block of the video data. in, In order to add the motion information of the first block to the table of the HMVP in response to determining that the first block is located at the lower right corner of the MER, the instruction causes the one or more processors to perform the following operations: Determine whether floor((xCb + cbWidth) / merSize) is greater than floor(xCb / merSize), where xCb represents the x-coordinate of the top-left sample of the first block, cbWidth represents the width of the first block, merSize represents the size of the MER, and floor() represents the floor function (rounding down). Determine whether floor((yCb + cbHeight) / merSize) is greater than floor(yCb / merSize), where yCb represents the y-coordinate of the top-left sample of the first block, and cbHeight represents the height of the first block; and In response to determining that floor((xCb + cbWidth) / merSize) is greater than floor(xCb / merSize) and in response to determining that floor((yCb + cbHeight) / merSize) is greater than floor(yCb / merSize), the motion information of the first block is added to the table of the HMVP. Wherein, the MER is the first MER, and the second block belongs to the second MER.

17. The computer-readable storage medium of claim 16, wherein, In order to use the HMVP table to decode the second block of the video data, the instruction causes the one or more processors to perform the following operations: For the second block, a candidate list of motion information is generated, wherein the candidate list includes candidates from the table of the HMVP; Select a candidate from the candidate list of motion vectors; and The selected candidate is used to decode the second block of video data.

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