Reference block fusion using derived vectors

Abstract

A method of encoding or decoding video data includes determining, for a chroma block of a picture, a luma block co-located with the chroma block; determining two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a position within the picture; fusing the two or more reference chroma blocks to generate a prediction sample of the chroma block; and performing block vector encoding or decoding on the chroma block based on the prediction sample.

Description

[0001] This application claims priority to U.S. Patent Application No. 18 / 625,670, filed April 3, 2024, and U.S. Provisional Application No. 63 / 495,979, filed April 13, 2023, the entire contents of which are hereby incorporated by reference. U.S. Patent Application No. 18 / 625,670, filed April 3, 2024, claims the benefit of U.S. Provisional Application No. 63 / 495,979, filed April 13, 2023. TECHNICAL FIELD

[0002] The present disclosure relates to video encoding and video decoding. BACKGROUND

[0003] Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite radio telephones, so-called “smart phones,” video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video coding techniques, such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4, Part 10, Advanced Video Coding (AVC), ITU-T H.265 / High Efficiency Video Coding (HEVC), ITU-T H.266 / Versatile Video Coding (VVC), and extensions of such standards, as well as proprietary video codecs / formats such as AOMedia Video 1 (AV1) developed by the Alliance for Open Media. By implementing such video coding techniques, video devices can more efficiently send, receive, encode, decode, and / or store digital video information.

[0004] Video coding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove redundancy inherent in video sequences. For block-based video coding, a video slice (e.g., a video picture or a portion of a video picture) can be partitioned into video blocks, which can also be referred to as coding tree units (CTUs), coding units (CUs), and / or coding nodes. Video blocks in the intra-coded (I) slices of a picture are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same picture. Video blocks in the inter-coded (P or B) slices of a picture can use spatial prediction with respect to reference samples in neighboring blocks in the same picture or temporal prediction with respect to reference samples in other reference pictures. Pictures can be referred to as frames, and reference pictures can be referred to as reference frames. SUMMARY

[0005] Typically, this disclosure describes techniques for generating prediction samples based on two or more reference chroma blocks and / or reference chroma blocks and one or more sub-blocks. For some video decoding techniques, reference blocks may be pointed to by vectors (e.g., motion vectors or block vectors), but the reference blocks may not match the original pixels (e.g., in a reference image of the motion vector or in the current image of the block vector). This disclosure describes example techniques for fusing multiple reference chroma blocks to remove errors between the original pixels and the prediction samples. That is, in one or more examples, the example techniques include generating prediction samples of chroma blocks based on two or more reference chroma blocks and / or generating prediction samples of decoding units (CUs) based on one or more sub-blocks and at least one reference block.

[0006] In one or more examples, a video decoder (e.g., a video encoder or video decoder) can be configured to determine two or more reference chroma blocks based on co-addressed luminance blocks that co-address with the chroma blocks. The video decoder can then fuse the two or more reference chroma blocks to generate prediction samples for encoding or decoding the chroma blocks.

[0007] In this way, compared to other techniques used to generate prediction samples, the example technique can generate prediction samples that serve as better predictors of chroma blocks. Therefore, compared to other techniques, the difference between the actual chroma blocks and the prediction samples can be reduced, resulting in reduced signaling and efficient bandwidth utilization.

[0008] In one example, this disclosure describes a method for encoding or decoding video data, the method comprising: for a chroma block of an image, determining a luma block co-located with the chroma block; determining two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; fusing the two or more reference chroma blocks to generate a prediction sample of the chroma block; and performing block vector encoding or decoding of the chroma block based on the prediction sample.

[0009] In one example, this disclosure describes an apparatus for encoding or decoding video data, the apparatus comprising: one or more memories configured to store the video data; and processing circuitry coupled to the one or more memories and configured to: determine, for a chroma block of an image, a luma block co-located with the chroma block; determine two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; fuse the two or more reference chroma blocks to generate a prediction sample of the chroma block; and perform block vector encoding or decoding of the chroma block based on the prediction sample.

[0010] In one example, this disclosure describes a computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to: determine, for a chroma block of an image, a luma block co-located with the chroma block; determine two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; fuse the two or more reference chroma blocks to generate a prediction sample of the chroma block; and perform block vector encoding or decoding of the chroma block based on the prediction sample.

[0011] 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, drawings, and claims. Attached Figure Description

[0012] Figure 1 This is a block diagram illustrating an example video encoding and decoding system that can perform the techniques of this disclosure.

[0013] Figure 2 This is a block diagram illustrating an example video encoder that can perform the techniques of this disclosure.

[0014] Figure 3 This is a block diagram illustrating an example video decoder that can perform the techniques of this disclosure.

[0015] Figure 4 This is a flowchart illustrating an example method for encoding the current block according to the technology of this disclosure.

[0016] Figure 5 This is a flowchart illustrating an example method for decoding the current block according to the technology of this disclosure.

[0017] Figure 6A and Figure 6B This is a conceptual diagram illustrating an example of a direct block vector (BV) that defines a chroma block.

[0018] Figure 7 This is a conceptual diagram illustrating an example of overlapping block motion compensation (OBMC) hybridization for OBMC modes at the decoder unit (CU) boundary.

[0019] Figure 8 This is a conceptual diagram illustrating an example of a reference block and an L-shaped template used in the intraTMP mode.

[0020] Figure 9 This is a conceptual diagram illustrating an example of blending reference chroma blocks.

[0021] Figure 10 This is a flowchart illustrating example methods of operation according to one or more examples described in this disclosure. Detailed Implementation

[0022] A video decoder (e.g., a video encoder or video decoder) can be configured to determine prediction samples (e.g., prediction blocks) for predicting the current block. For example, a video encoder can signal information indicating the residual values ​​between the prediction samples and the current block, and a video decoder can add the residual values ​​to the prediction samples to reconstruct the current block.

[0023] In some cases, the reference block used to generate the prediction sample may not match the original pixels of the current block. This disclosure describes example techniques for fusing multiple reference chroma blocks (e.g., using a derived set of weighting factors) to remove the error between the original pixels and the prediction sample. As an example, this disclosure describes a technique for fusing multiple reference chroma blocks derived from the block vectors of juxtaposed (i.e., co-located) luma blocks. As another example, this disclosure describes a technique for fusing a boundary sub-block (e.g., top and left boundary sub-blocks) of a luma or chroma CU with a reference block derived from information from neighboring blocks.

[0024] By generating predictive samples based on example fusion techniques, the predicted samples can be better predictions of the current block compared to other techniques. Therefore, the residual value can be smaller compared to other techniques, and the amount of information to be signaled can be reduced. Thus, example techniques can promote efficient bandwidth utilization in video decoding technologies, such as by generating predictive samples that are closer to the values ​​of the current block being encoded or decoded.

[0025] Figure 1 This is a block diagram illustrating an example video encoding and decoding system 100 capable of performing the techniques of this disclosure. The techniques of this disclosure generally relate to decoding (encoding and / or decoding) video data. Typically, video data includes any data used for processing video. Thus, video data may include raw, unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0026] 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 computer-readable medium 110. Source device 102 and destination device 116 can be or may include any of a wide variety of devices, such as desktop computers, laptop computers, mobile devices, tablet computers, set-top boxes, mobile phones such as smartphones, televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, broadcast receiver devices, etc. In some cases, source device 102 and destination device 116 may be equipped for wireless communication and are therefore referred to as wireless communication devices.

[0027] exist Figure 1 In the example, source device 102 includes a video source 104, memory 106, video encoder 200, and output interface 108. Destination device 116 includes an input interface 122, video decoder 300, memory 120, and display device 118. According to this disclosure, the video encoder 200 of source device 102 and the video decoder 300 of destination device 116 can be configured to apply a technique for reference block fusion using derived vectors. Thus, source device 102 represents an example of a video encoding device, while destination device 116 represents an example of a video decoding device. In other examples, the source device and destination device may include other components or 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 interface with an external display device, rather than including an integrated display device.

[0028] like Figure 1 The system 100 shown is merely an example. Typically, any digital video encoding and / or decoding device can perform techniques for reference block fusion using derived vectors. Source device 102 and destination device 116 are merely examples of such decoding devices, where source device 102 generates decoded video data for transmission to destination device 116. This disclosure refers to a “decoding” device as a device that performs the decoding (e.g., encoding and / or decoding) of data. Thus, video encoder 200 and video decoder 300 represent examples of decoding devices, specifically, video encoder and video decoder, respectively. In some examples, source device 102 and destination device 116 may operate in a substantially symmetrical manner, such that each of source device 102 and destination device 116 includes video encoding and decoding components. Therefore, system 100 may support one-way or two-way video transmission between source device 102 and destination device 116, for example, for video streaming, video playback, video broadcasting, or video telephony.

[0029] Typically, video source 104 represents the source of video data (i.e., raw, unencoded video data) and provides a sequential series of pictures (also referred to as "frames") of the video data to video encoder 200, which encodes the data for the pictures. Video source 104 of source device 102 may include video capture devices such as cameras, video archives containing previously captured raw video, and / or video feed interfaces for receiving 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 a decoding order for decoding. Video encoder 200 may generate a bitstream comprising encoded video data. The source device 102 can then output encoded video data to a computer-readable medium 110 via the output interface 108 for reception and / or retrieval, for example, by the input interface 122 of the destination device 116.

[0030] 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. Additionally or alternatively, memories 106 and 120 may store software instructions executable by, for example, video encoder 200 and video decoder 300. 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 encoded video data, such as 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.

[0031] Computer-readable medium 110 may represent any type of medium or device capable of transmitting encoded video data from source device 102 to destination device 116. In one example, computer-readable medium 110 represents a communication medium that enables source device 102 to directly transmit encoded video data 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 may modulate the transmitted signal including the encoded video data, and input interface 122 may demodulate the received transmitted signal. The communication medium may include any wireless or wired communication medium, such as radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may form part of a packet-based network such as a local area network, a wide area network, or a global network (such as the Internet). The communication medium may include a router, switch, base station, or any other equipment that may be useful for facilitating communication from source device 102 to destination device 116.

[0032] In some examples, source device 102 can output encoded data from output interface 108 to storage device 112. Similarly, destination device 116 can access encoded data from storage device 112 via input interface 122. Storage device 112 may include any data storage medium of various 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.

[0033] In some examples, source device 102 may output encoded video data to file server 114 or another intermediate storage device that may store the encoded video data generated by source device 102. Destination device 116 may access the stored video data from file server 114 via streaming or download.

[0034] File server 114 can be any type of server device capable of storing encoded video data and sending 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 FLUTE-based file delivery 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 may 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.

[0035] Destination device 116 can access encoded video data from file server 114 via any standard data connection, including an internet connection. This may 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, adapted 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 discussed above for retrieving or receiving media data from file server 114, or other such protocols for retrieving media data.

[0036] Output interface 108 and input interface 122 can 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 can be configured to transmit data such as encoded video data according to cellular communication standards such as 4G, 4G-LTE (Long Term Evolution), Advanced LTE, 5G, etc. In some examples where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 can be configured according to other wireless standards such as the IEEE 802.11 specification, the IEEE 802.15 specification (e.g., ZigBee), etc. TM ),Bluetooth TMStandards are used to transmit data such as encoded video data. In some examples, source device 102 and / or destination device 116 may include corresponding system-on-chip (SoC) devices. For example, source device 102 may include an SoC device for performing functions belonging to video encoder 200 and / or output interface 108, and destination device 116 may include an SoC device for performing functions belonging to video decoder 300 and / or input interface 122.

[0037] The technology disclosed herein can be applied to video decoding to support any multimedia application in a variety of multimedia applications, such as over-the-air television broadcasting, cable television transmission, satellite television transmission, internet streaming video transmission (such as HTTP-based Dynamic Adaptive Streaming (DASH)), digital video encoded onto data storage media, decoding of digital video stored on data storage media, or other applications.

[0038] 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 and 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., slices, pictures, picture groups, sequences, etc.). The display device 118 displays a decoded picture 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.

[0039] Despite Figure 1 Not shown, but in some examples, both the video encoder 200 and the video decoder 300 may 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.

[0040] Both the video encoder 200 and the video decoder 300 can 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 partially implemented in software, the device may store instructions for the software in a suitable non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to perform the technology of this disclosure. Each of the video encoder 200 and the video decoder 300 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined encoder / decoder (encoder-decoder) in the respective device. Devices including the video encoder 200 and / or the video decoder 300 may implement the video encoder 200 and / or the video decoder 300 in processing circuitry such as integrated circuits and / or microprocessors. Such devices may be wireless communication devices (such as cellular phones) or any other type of device described herein.

[0041] The video encoder 200 and video decoder 300 may operate according to a video decoding standard such as ITU-TH.265 (also known as High Efficiency Video Decoding (HEVC)) or its extensions (such as Multi-View and / or Scalable Video Decoding Extensions)). Alternatively, the video encoder 200 and video decoder 300 may operate according to other proprietary or industry standards such as ITU-TH.266 (also known as Multi-Functional Video Decoding (VVC)). In other examples, the video encoder 200 and video decoder 300 may operate according to proprietary video codecs / formats such as AOMedia Video1 (AV1), extensions to AV1, and / or subsequent versions of AV1 (e.g., AV2)). In other examples, the video encoder 200 and video decoder 300 may operate according to other proprietary formats or industry standards. However, the techniques disclosed herein are not limited to any particular decoding standard or format. Typically, the video encoder 200 and the video decoder 300 can be configured to perform the techniques of this disclosure by combining any video decoding technique that uses motion vectors (e.g., samples from a reference image different from the image containing the block being encoded or decoded) or block vectors (e.g., samples from the same image containing the block being encoded or decoded).

[0042] Typically, video encoder 200 and video decoder 300 perform block-based decoding of images. The term "block" generally refers to a structure that includes data to be processed (e.g., encoded, decoded, or otherwise used during encoding and / or decoding). 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 decode video data represented in YUV (e.g., Y, Cb, Cr) format. That is, instead of decoding the red, green, and blue (RGB) data used for images, video encoder 200 and video decoder 300 decode both the luminance and chrominance components, where the chrominance components may include both red and blue hue 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 to RGB format. Alternatively, preprocessing and post-processing units (not shown) may perform these conversions.

[0043] This disclosure generally relates to the decoding (e.g., encoding and decoding) of images to include processes of encoding or decoding data of the image. Similarly, this disclosure may relate to the decoding of blocks of images to include processes of encoding or decoding data for the blocks (e.g., prediction and / or residual decoding). Encoded video bitstreams typically include a series of values ​​for syntax elements representing decoding decisions (e.g., decoding modes) and the partitioning of images into blocks. Therefore, references to the decoding of an image or block should generally be understood as the decoded values ​​of the syntax elements that form the image or block.

[0044] HEVC defines various blocks, including decoding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video decoder (such as a video encoder 200) divides the decoding tree unit (CTU) into CUs based on a quadtree structure. That is, the video decoder divides the CTU and CU into four equal, non-overlapping squares, and each node of the quadtree has zero or four child nodes. Nodes without child nodes are called "leaf nodes," and the CU of such leaf nodes may include one or more PUs and / or one or more TUs. The video decoder may further divide the PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents the partitioning of the TU. In HEVC, the PU represents inter-frame prediction data, while the TU represents residual data. The CU after intra-frame prediction includes intra-frame prediction information, such as intra-frame mode indication.

[0045] As another example, video encoder 200 and video decoder 300 can be configured to operate according to VVC. According to VVC, the video decoder (such as video encoder 200) partitions the image into multiple 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 removes 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 quadtree partitioning, and a second level partitioned according to binary tree partitioning. The root node of the QTBT structure corresponds to a CTU. The leaf nodes of the binary tree correspond to CUs.

[0046] In the MTT partitioning structure, blocks can be divided using quadtree (QT) partitioning, binary tree (BT) partitioning, and one or more types of ternary tree (TT) partitioning (also known as triplet tree (TT)). A ternary tree or triplet tree partition is a partition in which a block is divided into three sub-blocks. In some examples, a ternary tree or triplet tree partition divides a block into three sub-blocks without dividing the original block through the center. Partition types in MTT (e.g., QT, BT, and TT) can be symmetric or asymmetric.

[0047] When operating according to the AV1 codec, the video encoder 200 and video decoder 300 can be configured to decode video data in blocks. In AV1, the largest decoded block that can be processed is called a superblock. In AV1, a superblock can be a 128x128 luma sample or a 64x64 luma sample. However, in subsequent video decoding formats (e.g., AV2), superblocks can be defined by different (e.g., larger) luma sample sizes. In some examples, the superblock is the top level of a block quadtree. The video encoder 200 can further divide the superblock into smaller decoded blocks. The video encoder 200 can use square or non-square partitions to divide the superblock and other decoded blocks into smaller blocks. Non-square blocks can include N / 2×N blocks, N×N / 2 blocks, N / 4×N blocks, and N×N / 4 blocks. The video encoder 200 and video decoder 300 can perform separate prediction and transform processing for each decoded block.

[0048] AV1 also defines video data tiles. A tile is a rectangular array of superblocks that can be decoded independently of other tiles. That is, the video encoder 200 and video decoder 300 can encode and decode the decoding blocks within a tile separately without using video data from other tiles. However, the video encoder 200 and video decoder 300 can perform filtering across tile boundaries. The tile size can be uniform or non-uniform. Tile-based decoding enables parallel processing and / or multithreading in the encoder and decoder implementations.

[0049] 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 the respective chroma components).

[0050] The video encoder 200 and the video decoder 300 can be configured to use quadtree partitioning, QTBT partitioning, MTT partitioning, superblock partitioning or other partitioning structures.

[0051] 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 a syntax structure for decoding the samples. A CTB can be an N×N block of samples of some value N, such that a partitioning method divides the components into CTBs. A component is an array or a single sample from one of the three arrays (luminance and two chrominance) constituting a 4:2:0, 4:2:2, or 4:4:4 color format image, or an array or a single sample constituting an array or array constituting a monochrome format image. In some examples, a decoded block is an M×N block of samples of values ​​M and N, such that a partitioning method divides the CTB into decoded blocks.

[0052] Blocks (e.g., CTUs or CUs) can be grouped in various ways within an image. As an example, a brick 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 syntax elements (e.g., such as in an image parameter set). A tile row refers to a rectangular area of ​​CTUs with a height specified by syntax elements (e.g., such as in an image parameter set) and a width equal to the width of the image.

[0053] In some examples, a tile can be divided into multiple bricks, each brick comprising one or more CTU rows within the tile. A tile that is not divided into multiple bricks can also be called a brick. However, bricks that are a true subset of a tile cannot be called a tile. Bricks in an image can also be arranged in slices. A slice can be an integer number of bricks in an image that can be uniquely contained within a single Network Abstraction Layer (NAL) unit. In some examples, a slice comprises multiple complete tiles or a continuous sequence of complete bricks comprising only one tile.

[0054] This disclosure uses "N×N" and "N by N" interchangeably to refer to the sample size of a block (such as a CU or other video block) in the vertical and horizontal dimensions, for example, 16×16 samples or 16 by 16 samples. Typically, a 16×16 CU will have 16 samples in the vertical direction (y = 16) and 16 samples in the horizontal direction (x = 16). Similarly, an N×NCU typically has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non-negative integer value. Samples in a CU may be arranged in rows and columns. Furthermore, a CU does not necessarily need to 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.

[0055] The video encoder 200 encodes video data representing prediction and / or residual information, as well as other information, for use in the control unit (CU). The prediction information indicates how the CU should be predicted to form a prediction block for the CU. The residual information typically represents the sample-by-sample difference between the prediction block and a sample of the CU before encoding.

[0056] To predict the Cubic Frame (CU), the video encoder 200 typically forms prediction blocks for the CU through inter-frame prediction or intra-frame prediction. Inter-frame prediction typically refers to predicting the CU from data in a previously decoded image, while intra-frame prediction typically refers to predicting the CU from data in a previously decoded image within the same frame. 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 to identify reference blocks that closely match the CU, for example, based on the differences between the CU and a reference block. The video encoder 200 can use sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), or other such difference calculations to compute difference metrics to determine whether a 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.

[0057] Some examples of VVC also provide an affine motion compensation mode, which can be viewed as an inter-frame prediction mode. 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).

[0058] 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 sixty-seven 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 of the current block (e.g., a block of CU), from which it predicts samples for the current block. Assuming the video encoder 200 decodes the CTU and CU in raster scan order (from left to right, from top to bottom), such samples can typically be located above, to the upper left, or to the left of the current block within the same frame as the current block.

[0059] 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, as well as the motion information for the corresponding mode. For example, for unidirectional or bidirectional inter-frame prediction, the video encoder 200 may encode motion vectors using Advanced Motion Vector Prediction (AMVP) or merging modes. The video encoder 200 may use similar modes to encode motion vectors used for affine motion compensation modes.

[0060] AV1 includes two common techniques for encoding and decoding blocks of video data. These two common techniques are intra-frame prediction (e.g., intra-frame prediction or spatial prediction) and inter-frame prediction (e.g., inter-frame prediction or temporal prediction). In the context of AV1, when using intra-frame prediction modes to predict blocks of video data for the current frame, the video encoder 200 and video decoder 300 do not use video data from other frames of the video data. For most intra-frame prediction modes, the video encoder 200 encodes blocks of the current frame based on the difference between sample values ​​in the current block and predicted values ​​generated from reference samples in the same frame. The video encoder 200 determines the predicted values ​​generated from the reference samples based on the intra-frame prediction mode.

[0061] After prediction (such as intra-frame or inter-frame prediction for a block), the video encoder 200 can compute residual data for the block. The residual data (such as a residual block) represents the sample-wise difference between the block and the prediction block used to form the block, which is 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 Correlated Inseparable Quadratic Transform (MDNSST), a Signal Correlation Transform, a Karhunen-Loeve Transform (KLT), etc. The video encoder 200 produces transform coefficients after applying one or more transforms.

[0062] As noted above, after any transformation that produces the transform coefficients, the video encoder 200 may perform quantization on the transform coefficients. Quantization typically refers to a process in which the transform coefficients are quantized to 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 down 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 bit-by-bit right shift of the value to be quantized.

[0063] After quantization, the video encoder 200 can scan the transform coefficients to generate a one-dimensional vector from a two-dimensional matrix containing 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 that 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 decoding (CABAC). The video encoder 200 can also entropy-encode the values ​​of syntax elements describing metadata associated with the encoded video data for use by the video decoder 300 when decoding the video data.

[0064] 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.

[0065] The video encoder 200 may further generate syntax data for the video decoder 300, such as block-based syntax data, image-based syntax data, and sequence-based syntax data, for example, in image headers, block headers, and slice headers, or generate other syntax data such as sequence parameter sets (SPS), image parameter sets (PPS), or video parameter sets (VPS). The video decoder 300 may also decode such syntax data to determine how to decode the corresponding video data.

[0066] In this manner, the video encoder 200 can generate a bitstream comprising encoded video data, such as syntax elements describing the partitioning 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.

[0067] Typically, the video decoder 300 performs the reverse process of the video encoder 200 to decode the encoded video data of the bitstream. For example, the video decoder 300 may use CABAC to decode the values ​​of syntax elements used for the bitstream in a manner substantially similar to, but reversed, the CABAC encoding process of the video encoder 200. Syntax elements may define partitioning information for dividing a picture into CTUs and for partitioning each CTU according to a corresponding partitioning structure such as a QTBT structure to define the CUs of the CTU. Syntax elements may further define prediction and residual information for video data blocks (e.g., CUs).

[0068] 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 reconstruct the residual block for the block. The video decoder 300 uses a prediction mode (intra-frame prediction or inter-frame prediction) and associated prediction information (e.g., motion information for inter-frame prediction) to form a prediction block for the block. The video decoder 300 can then combine the prediction block and the residual block (on a sample-by-sample basis) to reconstruct the original block. The video decoder 300 can perform additional processing, such as performing a deblocking process to reduce visual artifacts along the block boundaries.

[0069] This disclosure may generally relate to "signaling" certain information (such as syntax elements). The term "signaling" can generally refer to the communication of values ​​and / or other data of syntax elements used to decode encoded video data. That is, video encoder 200 may signal the values ​​of syntax elements in the bitstream. Generally, signaling refers to generating values ​​in the bitstream. As noted above, source device 102 may transmit the bitstream to destination device 116 substantially in real time or not in real time (such as when syntax elements are stored in storage device 112 for later retrieval by destination device 116).

[0070] As noted above, Multifunctional Video Decoding (VVC) is a new video decoding standard developed by the Joint Video Experts Group (JVET) of ITU-T and ISO / IEC to achieve higher compression capabilities than HEVC for a wide range of applications. The VVC specification was completed in July 2020 and published by both ITU-T and ISO / IEC. The VVC specification defines standard bitstream and picture formats, High-Level Syntax (HLS) and decoding unit-level syntax, as well as parsing and decoding procedures. VVC also specifies profile / layer / level (PTL) constraints, byte stream formats, hypothetical reference decoders, and supplementary enhancement information (SEI) in its appendices.

[0071] Since April 2021, JVET has been developing Enhanced Compression Model (ECM) software: M.Coban, FLLéannec, MGSarwer, and J. "Algorithm description of Enhanced Compression Model 8 (ECM 8)," JVET-AC2025, April 2023, to enhance compression capabilities beyond VVC. The set of decoding tools in ECM software includes all functional blocks in the hybrid video decoding framework, including intra-frame prediction, inter-frame prediction, transform and coefficient decoding, intra-loop filtering, and entropy decoding. The example techniques described in this disclosure can be applied to ECM and video codecs such as VVC, AV1, etc.

[0072] In ECM-8.0, there are 13 intra-frame modes for chroma intra-mode decoding. These intra-frame modes are classified into two chroma mode lists: the CCLM mode list and the non-CCLM mode list. The CCLM mode list includes six cross-component linear model modes: LM and LM_L, LM_T, MMLM, MMLM_L, and MMLM_T. The non-CCLM mode list includes one direct BV (DBV) mode (JVET-AC0071, titled "EE2-3.1: Direct block vector mode for chroma prediction", Huo et al.), one chroma DIMD mode (JVET-Z0051, titled "Ee2-1.2: On chromaintra prediction", Li et al.), and five traditional intra-frame modes: direct mode (DM) and default mode.

[0073] like Figure 6A and Figure 6BAs shown, if the selected luminance CU is decoded by intraTMP (intra-template matching prediction) or IBC (intra-block copying), the concept of DBV will be derived from the chrominance BV (bvC[0], bvC[1]) based on the corresponding luminance BV of the juxtaposed luminance CUs (chosen from one of the following CUs: c, TL, TR, BL, BR). The corresponding offset position (xCb+bvC[0], yCb+bvC[1]) is determined by using the current chrominance block's location (xCb, yCb) and the current chrominance block's block vector (bvC), and block copying prediction is performed.

[0074] For example, Figure 6A Luminance component 600 and chrominance component 602 are illustrated. The current chrominance block is illustrated as CU 603 in chrominance component 602. Example luminance CUs that co-address with the chrominance blocks are illustrated as c, TL, TR, BL, and BR. Figure 6B This example illustrates the current block 604 (e.g., a chroma block) and a reference block 606, which can be pointed to using the block vector (bvC) of the co-located luma block (e.g., ...). Figure 6A (One example from the examples shown).

[0075] Overlapping Block Motion Compensation (OBMC) is a predictive hybrid method based on current MV information and neighboring MV information. Two OBMC modes exist: CU boundary OBMC mode and sub-block boundary OBMC mode.

[0076] Figure 7 This is a conceptual diagram illustrating an example of overlapping block motion compensation (OBMC) hybridization for OBMC modes at the decoder unit (CU) boundary. Figure 7 The CU 700 is shown as an example. For example... Figure 7 As shown, when using CU boundary mode, the original prediction block (referred to as "original block") that uses the current CU MV is mixed with another prediction block (referred to as "OBMC block") that uses the adjacent CU MV. In some techniques, OBMC is only applied to inter-frame mode and inter-frame merge mode, which may be a limitation on the OBMC that the example techniques can address.

[0077] For example, a motion vector of CU 700 can point to block B1 702. Block B1 702 is an example of a raw block. A motion vector for a block above CU 700 can point to block BT (block top) 706. Block BT 706 is an example of an OBMC block. Video encoder 200 and video decoder 300 can multiply samples of block B1 702 by "a" and multiple samples of block BT 706 by "b", and sum the results to generate a mixed block 710. In this case, the values ​​of a and b are based on the distance of the portion co-located with block B1 702 to the boundary of CU 700 (e.g., the left or right boundary).

[0078] As another example, a motion vector of CU 700 can point to block B2 704. Block B2 704 is an example of a raw block. A motion vector for the block to the left of CU 700 can point to block BL (left side of block) 708. Block BL 708 is an example of an OBMC block. Video encoder 200 and video decoder 300 can multiply samples of block B2 704 by "a" and multiple samples of block BL 708 by "b", and sum the results to generate a mixed block 712. In this case, the values ​​of a and b are based on the distance of the portion co-located with block B2 704 to the boundary of CU 700 (e.g., above or below the boundary).

[0079] ECM employs, for example, Figure 8 The intraTMP pattern shown (JVET-AB0130, named "EE2-1.14: IntraTMPadaptation for camera-captured content", Naser et al.) is used to match the reference block whose L-shaped template differs least from the L-shaped template of the current block 800. Then, the matched reference block 802 is copied to the current block 800. R1, R2, R3, and R4 are the search areas.

[0080] In some cases, reference blocks may not match the original pixels. This disclosure describes example techniques for fusing multiple reference blocks (e.g., using a derived set of weighting factors) to remove errors between the original pixels and the predicted samples. One example of these techniques includes fusing multiple reference chroma blocks derived from the block vectors (BVs) of juxtaposed (i.e., co-located) luma blocks. Another example of these techniques includes fusing one of the top and left boundary sub-blocks of a luma or chroma CU with a reference block derived from information from neighboring blocks. To the extent possible, example techniques may also be combined. For example, example techniques are described in relation to the fusion of reference blocks derived from direct BVs and the fusion of reference sub-blocks derived from neighboring blocks. However, to the extent possible, these example techniques may be combined or performed individually.

[0081] In contrast to the fusion of reference blocks derived directly from BV, the video encoder 200 or the video decoder 300 can fuse multiple reference chroma blocks derived from chroma BV. Figure 9 An example of fusion of two reference chroma blocks 902A and 902B for chroma block 900 is shown. In the fusion, the video encoder 200 and the video decoder 300 may average or scale and sum the samples of two or more reference chroma blocks, as described in more detail below.

[0082] In one example, if the selected luma block is decoded by intraTMP or IBC, then as follows Figure 6A As shown, the chromaticity BV is derived from the luminance BV of juxtaposed luminance blocks. As an example, assume... Figure 9 The chroma block 900 corresponds to Figure 6A CU 603. In this example, chroma block 900 is... Figure 6A The luminance blocks TL, TR, C, BR, and BL of luminance component 600 are co-addressed (i.e., arranged side-by-side). There may be more or fewer luminance blocks co-addressed with chrominance block 900, and for illustrative purposes, luminance blocks TL, TR, C, BR, and BL are used.

[0083] In one or more examples, video encoder 200 and video decoder 300 can determine the block vectors (BVs) of luma blocks TL, TR, C, BR, and BL. Based on the BVs of the luma blocks, video encoder 200 and video decoder 300 can determine reference chroma blocks 902A and 902B for chroma block 900. For example, suppose bv1 is... Figure 6A bv2 is a scaled version of the block vector of one of the luma blocks TL, TR, C, BR, and BL, and bv2 is Figure 6A The block vector of the luma block 600 is a scaled version of the block vector of another of the luma blocks TL, TR, C, BR, and BL. Because the chroma component 600 can be downsampled relative to the luma component 602, the video encoder 200 and the video decoder 300 can scale the block vector of the luma block.

[0084] There can be various ways in which the video encoder 200 and video decoder 300 can determine the reference chroma blocks used for fusion. As an example, the video encoder 200 and video decoder 300 can determine the block vectors of two or more co-located luma blocks that co-address with chroma block 900. The video encoder 200 and video decoder 300 can construct a list of chroma block vectors from the luma block vectors of the co-located luma blocks. For example, the video encoder 200 and video decoder 300 can determine the block vector of luma block TL and add that block vector or a scaled version of it to the list of chroma block vectors. The video encoder 200 and video decoder 300 can determine the block vector of luma block TR and add that block vector or a scaled version of it to the list of chroma block vectors, and so on.

[0085] In one example, video encoder 200 can signal the index of an identifier block vector in a chroma block vector list, and video decoder 300 can receive that index. Video encoder 200 and video decoder 300 can use the block vectors retrieved from the chroma block vector list to determine two or more reference chroma blocks (e.g., reference chroma block 902A and reference chroma block 902B). Video encoder 200 and video decoder 300 can then fuse the two or more reference chroma blocks to generate a predicted sample of chroma block 900.

[0086] In some examples, after initially constructing the chroma block vector list, the video encoder 200 and video decoder 300 can reorder the chroma block vector list to generate a final chroma block vector list. For example, block vector candidate reordering can be performed by comparing templates adjacent to a reference block with templates adjacent to the current block.

[0087] For example, video encoder 200 and video decoder 300 can determine corresponding candidate reference chroma blocks based on the corresponding block vectors of luma blocks. In other words, for each block vector of two or more co-located luma blocks, video encoder 200 and video decoder 300 can determine candidate reference chroma blocks. As an example, video encoder 200 and video decoder 300 can utilize the block vector of luma block C (e.g., based on scaling the block vector of luma block C if necessary) to determine candidate block vectors and determine the candidate reference chroma blocks pointed to by the candidate block vectors. Video encoder 200 and video decoder 300 can repeat such operations for each block vector in the block vectors of the co-located luma blocks to be evaluated. In this way, video encoder 200 and video decoder 300 determine a set of candidate reference chroma blocks. The actual reference chroma blocks used can be drawn from this set of candidate reference chroma blocks.

[0088] The video encoder 200 and video decoder 300 can determine the corresponding cost of the respective candidate reference chroma blocks. One example method for determining the corresponding cost is based on template matching techniques. For example... Figure 9 As shown, template 904 includes a sample adjacent to chroma block 900. Template 906 includes a sample adjacent to reference chroma block 902A, and template 908 includes a sample adjacent to reference chroma block 902B.

[0089] The video encoder 200 and video decoder 300 can determine the corresponding cost based on comparing template 904 with corresponding templates of candidate reference chroma blocks (e.g., comparing template 904 with template 906; comparing template 904 with template 908, and so on). One example comparison technique is to determine the sum of absolute differences (SAD). Another example comparison technique is the mean squared error (MSE). Other example comparison techniques are possible.

[0090] Using the corresponding costs of the candidate reference chroma blocks, the video encoder 200 and video decoder 300 can reorder the chroma block vector list. For example, the video encoder 200 and video decoder 300 can reorder the chroma block vector list such that candidate reference chroma blocks with lower costs (e.g., better match with template 904) are placed earlier in the chroma block vector list, while candidate reference chroma blocks with higher costs (e.g., poorer match with template 904) are placed later in the chroma block vector list.

[0091] In some examples, the chroma block vectors of adjacent chroma blocks (e.g., the chroma block adjacent to chroma block 900) may also be included in the chroma block vector list. The video encoder 200 and the video decoder 300 may similarly determine the corresponding costs of candidate reference chroma blocks pointed to by the block vectors of adjacent chroma blocks and reorder the chroma block vector list accordingly.

[0092] Video encoder 200 can signal an index in a list of chroma block vectors (e.g., after reordering), and video decoder 300 can receive that index. Video decoder 300 can then determine a reference chroma block (e.g., based on the chroma block pointed to by the block vector retrieved from the list of chroma block vectors, possibly after scaling). Video encoder 200 and video decoder 300 can fuse the reference chroma block to generate a predicted sample of chroma block 900.

[0093] However, in some examples, signaling in the chroma block vector list may not be necessary. For example, after the video encoder 200 and video decoder 300 determine which candidate reference chroma blocks have the lowest response cost, they may select N (e.g., 2 to 5) candidate reference chroma blocks with the lowest response cost as reference chroma blocks. The video encoder 200 and video decoder 300 may fuse the reference chroma blocks to generate a prediction sample. Thus, in one or more examples, the reference chroma blocks with the minimum template matching (TM) cost are fused to generate a predictor (e.g., a prediction sample) for the current chroma block 900.

[0094] In other words, for a chroma block of an image, the video encoder 200 and video decoder 300 can determine the luma block co-located with the chroma block, and determine two or more reference chroma blocks based on the block vector of the luma block, the block vector pointing to a location within the image. The video encoder 200 and video decoder 300 can generate a prediction sample of the chroma block based on the two or more reference chroma blocks (e.g., by fusing two or more reference chroma blocks), and perform block vector encoding or decoding of the chroma block based on the prediction sample (e.g., encoding or decoding the chroma block based on a prediction sample generated from a sample in the same image as the chroma block).

[0095] Video encoder 200 and video decoder 300 can fuse two or more reference chroma blocks to generate prediction samples. Fusing two or more reference chroma blocks (e.g., reference chroma block 902A and reference chroma block 902B) can include averaging the two or more reference chroma blocks and / or scaling and summing the two or more reference chroma blocks, as described in more detail. For example, video encoder 200 and video decoder 300 can determine corresponding weights for the two or more reference chroma blocks, wherein fusion includes fusing the two or more reference chroma blocks based on the corresponding weights.

[0096] As described above, video encoder 200 and video decoder 300 can compare templates adjacent to a reference chroma block (e.g., templates 906 and 908) with templates adjacent to the current chroma block 900 (e.g., template 904) to determine costs and which reference chroma blocks to use. That is, multiple block vectors of co-located luma blocks can exist, and each block reference can point to a candidate reference chroma block (e.g., "candidate," because the reference chroma block may be selected, but it may not be selected as a reference chroma block). Therefore, video encoder 200 and video decoder 300 can determine the corresponding candidate reference chroma blocks based on each block vector in the block vectors of the luma blocks, and determine the corresponding cost of the corresponding candidate reference chroma blocks. That is, video encoder 200 and video decoder 300 can determine the cost associated with each candidate reference chroma block in the candidate reference chroma blocks. Video encoder 200 and video decoder 300 can select two or more candidate reference chroma blocks from the candidate reference chroma blocks based on the corresponding costs to determine two or more reference chroma blocks. For example, determining the corresponding cost may include determining the amount of matching between a first template (e.g., templates 906 and 908) adjacent to the corresponding candidate reference chroma block and a second template (e.g., template 904) adjacent to chroma block 900.

[0097] To fuse reference chroma blocks, video encoder 200 and video decoder 300 can apply weighting factors to each reference chroma block. For example, suppose reference chroma blocks 902A and 902B are selected as reference chroma blocks to be fused. Video encoder 200 and video decoder 300 can determine a first weight applied to the samples of reference chroma block 902A and a second weight applied to the samples of reference chroma block 902B. Video encoder 200 and video decoder 300 can add the weighted samples together to determine the predicted samples. In some examples, video encoder 200 and video decoder 300 can simply average (e.g., unweighted) the samples of reference chroma blocks 902A and 902B to fuse reference chroma blocks 902A and 902B and generate the predicted samples.

[0098] There can be various ways in which the video encoder 200 and video decoder 300 can determine the weights (also called weighting factors). For example, the weighting factors of the fusion can be derived from the TM (template matching) cost, where a larger weighting factor is applied to the reference block if the TM cost is low. In some examples, the weighting factors are derived by minimizing the mean squared error (MMSE) between the sum of the templates of the reference chroma blocks used and the template of the current block.

[0099] For example, suppose video encoder 200 and video decoder 300 determine a first TM cost (e.g., SAD) between templates 906 and 904 and a second TM cost between templates 908 and 904. Assume the first TM cost is less than the second TM cost. In this example, the weighting applied by video encoder 200 and video decoder 300 to samples of reference chroma block 902A may be greater than the weighting applied to samples of reference chroma block 902B.

[0100] Other methods of determining weights may exist. In some examples, the video encoder 200 and video decoder 300 can determine the weighting factor derivation operation. For example, the video encoder 200 can signal an index in the list of weighting factor derivation techniques, and the video decoder 300 can receive that index to indicate which weighting factor derivation operation was used for the current chroma block 900. In one example, there are four fusion modes: (1) no fusion; (2) fusion with weights derived from TM cost; (3) fusion with weights derived from MMSE; and (4) fusion with fixed weights. Fixed weights can be signaled or determined.

[0101] In the above example, it is not necessary to consider every block vector of every co-located luma block. For example, the number of block vectors derived from the luma juxtaposition (co-located) blocks is determined based on the TM cost. For example, if the TM cost i is close to the minimum TM cost j (e.g., TM_cost_i < threshold * TM_cost_j, where the threshold is a pre-assigned positive value), then the video encoder 200 and the video decoder 300 can fuse the reference chroma block "i" with the optimal reference chroma block "j".

[0102] This disclosure describes extending OBMC to CUs decoded in non-inter-frame modes (e.g., intra-frame mode, intraTMP mode, etc.) relative to merging reference sub-blocks derived from neighboring blocks. When OBMC is applied to a CU decoded in intraTMP mode, if neighboring blocks are decoded by IBC or intraTMP, the boundary sub-blocks (e.g., Figure 7 Blocks B1 702 and B2 704 in the middle) and the BV of the adjacent blocks (e.g., Figure 7 Reference blocks derived from blocks BT 706 and BL 708 in the model are merged. In another case, if adjacent blocks are decoded in inter-frame mode or merge mode, the boundary sub-blocks (e.g., Figure 7 Blocks B1 702 and B2 704 in the middle) and the MV of adjacent blocks (e.g., Figure 7 Reference block fusion is derived from blocks BT 706 and BL 708 in the OBMC. The same fusion method can be applied when the OBMC is applied to a CU decoded in conventional intra-frame mode.

[0103] When OBMC is applied to a CU block (e.g., whether in inter-frame mode or non-inter-frame mode), the video encoder 200 and video decoder 300 can use the BV of the adjacent block (e.g., when the adjacent block is decoded by IBC or intraTMP) if the adjacent block is not. Figure 7 Blocks BT 706 and BL 708 in the code are used to generate reference sub-blocks to correspond with boundary sub-blocks (e.g., Figure 7 The video encoder 200 and video decoder 300 can fuse blocks B1 702 and B2 704 in the CU block. When the OBMC is applied to the CU block (whether in inter-frame mode or non-inter-frame mode), if the BV and MV of the adjacent blocks are not available, the video encoder 200 and video decoder 300 can be based on the adjacent blocks (e.g., Figure 7 The BV is derived from the TM cost used in the intraTMP of blocks BT 706 and BL 708 in the block. The reference sub-block located by the derived BV can then be compared with the boundary sub-block (e.g., ...). Figure 7 The blocks B1 702 and B2 704 in the middle are merged.

[0104] Therefore, in one or more examples, the video encoder 200 and the video decoder 300 can be configured to determine one or more sub-blocks of a decoding unit (CU) and determine at least one reference block based on at least one vector of at least one block that is close to the CU. The video encoder 200 and the video decoder 300 can generate prediction samples of the CU based on one or more sub-blocks and at least one reference block, and encode or decode the CU based on the prediction samples.

[0105] In some examples, one or more sub-blocks of a CU are located at the boundaries of the CU. For example, one or more sub-blocks are the top and left boundary sub-blocks of the CU. In some examples, the CU is a luminance CU or a chrominance CU.

[0106] To generate prediction samples, the video encoder 200 and the video decoder 300 may fuse one or more sub-blocks and at least one reference block. Fusion may include averaging the one or more sub-blocks and at least one reference block; and / or scaling and summing the one or more sub-blocks and at least one reference block.

[0107] Figure 2 This is a block diagram illustrating an example video encoder 200 that can perform the techniques of this disclosure. Figure 2 This disclosure is provided for illustrative purposes and should not be construed as a limitation on the techniques extensively illustrated and described herein. For illustrative purposes, this disclosure describes the video encoder 200 in accordance with VVC and HEVC techniques. However, the techniques of this disclosure can be performed by video encoding devices configured for other video decoding standards and video decoding formats, such as AV1 and subsequent formats of AV1 video decoding.

[0108] exist Figure 2 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 encoding unit 220. Any 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 212, reconstruction unit 214, filter unit 216, DPB 218, and entropy encoding unit 220 can be implemented in one or more processors or in processing circuitry. For example, the units of the video encoder 200 can be implemented as one or more circuit or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Furthermore, the video encoder 200 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0109] Video data storage 230 can store video data to be encoded by components of video encoder 200. Video encoder 200 can receive data from, for example, video source 104 (…). Figure 1 The video data memory 230 receives video data stored in the video data memory 230. The DPB 218 can act as a reference picture memory, storing reference video data for use when the video encoder 200 predicts subsequent video data. The video data memory 230 and DPB 218 can be formed from any of a variety of memory devices, such as dynamic random access memory (DRAM) (including synchronous DRAM (SDRAM)), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The video data memory 230 and DPB 218 can be provided by the same memory device or separate memory devices. In various examples, the video data memory 230 can be on-chip (as illustrated) with other components of the video encoder 200, or off-chip relative to those components.

[0110] In this disclosure, references to video data memory 230 should not be construed as limited to memory inside video encoder 200 (unless otherwise stated) or memory outside video encoder 200 (unless otherwise stated). Rather, references to video data memory 230 should be understood as reference memory storing video data received by video encoder 200 for encoding (e.g., video data for the current block to be encoded). Figure 1 The memory 106 can also provide temporary storage for the outputs from various units of the video encoder 200.

[0111] Examples Figure 2 Various units help understand the operations performed by the video encoder 200. Units can be implemented as fixed-function circuits, programmable circuits, or combinations thereof. A fixed-function circuit is a circuit that provides specific functionality and is pre-defined for the operations that can be performed. A programmable circuit is a circuit that can be programmed to perform various tasks and provides flexible functionality for the operations that can be performed. For example, a programmable circuit can execute software or firmware that causes the programmable circuit to operate in a manner defined by the instructions of the software or firmware. 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 generally immutable. In some examples, one or more units in the unit may be different circuit blocks (fixed-function or programmable), and in some examples, one or more units in the unit may be integrated circuits.

[0112] 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 1 The video encoder 200 may store instructions (e.g., object code) of the software received and executed by the video encoder 200, or another memory (not shown) within the video encoder 200 may store such instructions.

[0113] The video data storage unit 230 is configured to store received video data. The video encoder 200 can retrieve 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 raw video data to be encoded.

[0114] 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 additional functional units for performing video prediction based on other prediction modes. As an example, the mode selection unit 202 may include a palette unit, an intra-frame 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.

[0115] Mode selection unit 202 typically coordinates multiple coding channels to test combinations of coding parameters and the resulting rate-distortion values ​​for such combinations. Coding parameters may include the CTU-CU partitioning, the prediction mode for the CU, the transformation type of the residual data for the CU, the quantization parameters of the residual data for the CU, etc. Mode selection unit 202 can ultimately select a combination of coding parameters that has a better rate-distortion value compared to other tested combinations.

[0116] Video encoder 200 can divide images retrieved from video data storage 230 into a series of CTUs and encapsulate one or more CTUs within slices. Mode selection unit 202 can divide the CTUs of an image according to a tree structure (such as an MTT structure, QTBT structure, superblock structure, or the quadtree structure described above). As described above, video encoder 200 can form one or more CUs by dividing CTUs according to a tree structure. Such CUs are also commonly referred to as "video blocks" or "blocks".

[0117] 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, in HEVC, the overlapping portion of PU and TU). 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 decoded pictures stored in DPB 218). Specifically, motion estimation unit 222 may calculate values ​​representing the similarity between a 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 difference (MSD), etc. Motion estimation unit 222 may typically perform these calculations using sample-by-sample differences between the current block and the reference blocks under consideration. Motion estimation unit 222 may identify reference blocks with the lowest values ​​produced by these calculations to indicate the reference block that best matches the current block.

[0118] Motion estimation unit 222 can generate one or more motion vectors (MVs) that define the location of a reference block in a reference image relative to the location of the 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 a prediction block. For example, motion compensation unit 224 can use the motion vectors to retrieve data for a reference block. As another example, where the motion vectors have fractional sample precision, motion compensation unit 224 can interpolate the values ​​of the prediction block based on one or more interpolation filters. Furthermore, for bidirectional inter-frame prediction, motion compensation unit 224 can retrieve data for two reference blocks identified by corresponding motion vectors and combine the retrieved data, for example, by per-sample averaging or weighted averaging.

[0119] When operating according to the AV1 video decoding format, the motion estimation unit 222 and the motion compensation unit 224 can be configured to encode the decoded blocks of video data (e.g., both luma and chroma decoded blocks) using translational motion compensation, affine motion compensation, overlap block motion compensation (OBMC), and / or composite inter-intra-frame prediction.

[0120] As another example, for intra-prediction or intra-prediction decoding, intra-prediction unit 226 may generate a prediction block from samples adjacent to the current block. For example, for directional mode, intra-prediction unit 226 may typically mathematically combine the values ​​of adjacent samples and fill these calculated values ​​across the current block in a defined direction to produce a prediction block. As another example, for DC mode, intra-prediction unit 226 may calculate the average of the adjacent samples of the current block and generate a prediction block to include the resulting average for each sample of the prediction block.

[0121] When operating according to the AV1 video decoding format, the intra-frame prediction unit 226 can be configured to encode decoded blocks of video data (e.g., both luma and chroma decoded blocks) using directional intra-frame prediction, non-directional intra-frame prediction, recursive filter intra-frame prediction, luma-chroma (CFL) prediction, intra-block copy (IBC), and / or palette modes. The mode selection unit 202 may include additional functional units for performing video prediction based on other prediction modes.

[0122] Mode selection unit 202 provides a 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 decoding modulation (RDPCM). In some examples, residual generation unit 204 may be formed using one or more subtractor circuits performing binary subtraction.

[0123] 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 noted above, the size of a CU can refer to the size of its luma decoding block, while the size of a PU can refer to the size of the luma prediction unit within that PU. Assuming a particular CU size is 2N×2N, video encoder 200 can support PU sizes of 2N×2N or N×N for intra-frame prediction, and symmetric PU sizes of 2N×2N, 2N×N, N×2N, N×N, or similar for inter-frame prediction. Video encoder 200 and video decoder 300 can also support asymmetric partitioning for PU sizes of 2N×nU, 2N×nD, nL×2N, and nR×2N for inter-frame prediction.

[0124] In an example where mode selection unit 202 does not further divide the CU into PUs, each CU can be associated with a luma decoding block and a corresponding chroma decoding block. As mentioned above, the size of the CU can refer to the size of the luma decoding 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.

[0125] For other video decoding techniques, such as intra-block copy mode decoding, affine mode decoding, and linear model (LM) mode decoding, as some 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 indicating how the block is reconstructed based on a selected palette. In such modes, mode selection unit 202 may provide these syntax elements to entropy coding unit 220 for encoding.

[0126] As described above, the residual generation unit 204 receives video data for the current block and the corresponding prediction block. Then, the residual generation unit 204 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.

[0127] 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 primary transformations and secondary transformations (such as rotation transformations). In some examples, transform processing unit 206 does not apply any transformations to the residual block.

[0128] When operating according to AV1, transform processing unit 206 may apply one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a "transform coefficient block"). Transform processing unit 206 may apply various transforms to the residual block to form the transform coefficient block. For example, transform processing unit 206 may apply a combination of horizontal / vertical transforms, which may include the Discrete Cosine Transform (DCT), the Asymmetric Discrete Sine Transform (ADST), the Reversed ADST (e.g., ADST in reverse order), and the Identity Transform (IDTX). When using the Identity Transform, the transform is skipped in either the vertical or horizontal direction. In some examples, transform processing may be skipped entirely.

[0129] Quantization unit 208 quantizes the transform coefficients in a transform coefficient block to produce a quantized transform coefficient block. Quantization unit 208 quantizes the transform coefficients of the transform coefficient block according to 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 cause information loss, and therefore, the quantized transform coefficients may have lower accuracy compared to the original transform coefficients produced by transform processing unit 206.

[0130] The inverse quantization unit 210 and the inverse transform processing unit 212 can apply inverse quantization and inverse transform, respectively, to the quantized transform coefficient block to reconstruct the residual block based on the transform coefficient block. The reconstruction unit 214 can generate a reconstructed block corresponding to the current block (although potentially with some degree of distortion) based on the reconstructed residual block and the prediction block generated by the mode selection unit 202. 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.

[0131] Filter unit 216 may perform one or more filtering operations on the reconstructed block. For example, filter unit 216 may perform a deblocking operation to reduce block artifacts along the edges of the CU. In some examples, the operation of filter unit 216 may be skipped.

[0132] When operating according to AV1, filter unit 216 may perform one or more filtering operations on the reconstructed block. For example, filter unit 216 may perform a deblocking operation to reduce block artifacts along the edges of the CU. In other examples, filter unit 216 may apply a constrained direction enhancement filter (CDEF) after deblocking, and may include the application of a non-separable, nonlinear, low-pass directional filter based on the estimated edge direction. Filter unit 216 may also include a loop recovery filter applied after CDEF, and may include a separable symmetric normalized Wiener filter or a dual-guided filter.

[0133] The video encoder 200 stores reconstructed blocks in the DPB 218. For example, in an example where the filter unit 216 is not operated, the reconstruction unit 214 may store reconstructed blocks in the DPB 218. In an example where the filter unit 216 is operated, the filter unit 216 may store filtered reconstructed blocks in the DPB 218. The motion estimation unit 222 and the motion compensation unit 224 may retrieve a reference picture formed by the reconstructed (and potentially filtered) blocks from the DPB 218 to perform inter-frame prediction of blocks in subsequently encoded pictures. Additionally, the intra-frame prediction unit 226 may use the reconstructed blocks of the current picture in the DPB 218 to perform intra-frame prediction of other blocks in the current picture.

[0134] 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 a block of quantized transform coefficients 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 the syntax elements (another example of video data) to generate entropy-coded data. For example, entropy coding unit 220 can perform context-adaptive variable-length decoding (CAVLC), CABAC, variable-to-variable (V2V) length decoding, syntax-based context-adaptive binary arithmetic decoding (SBAC), probability interval partitioning entropy (PIPE) decoding, exponential Golomb coding, or another type of entropy coding operation on the data. In some examples, entropy coding unit 220 can operate in a bypass mode where syntax elements are not entropy-encoded.

[0135] The video encoder 200 can output a bitstream that includes the entropy-encoded syntax elements required to reconstruct slices or blocks of images. Specifically, the entropy coding unit 220 can output a bitstream.

[0136] According to AV1, entropy coding unit 220 can be configured as a symbol-to-symbol adaptive multi-symbol arithmetic decoder. The syntax elements in AV1 include an N-element alphabet, and the context (e.g., a probability model) includes a set of N probabilities. Entropy coding unit 220 can store the probabilities as an n-bit (e.g., 15-bit) cumulative distribution function (CDF). Entropy coding unit 220 can perform recursive scaling using an update factor based on the alphabet size to update the context.

[0137] The operations described above are relative to blocks. Such descriptions should be understood as operations applied to luma decoding blocks and / or chroma decoding blocks. As described 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.

[0138] In some examples, it is not necessary to repeat the operations performed relative to the luma decoder for the chroma decoder block. As an example, the operations for identifying the motion vector (MV) and reference image of the luma decoder block do not need to repeat the MV and reference image used to identify the chroma block. Specifically, the MV used for the luma decoder block can be scaled to determine the MV used for the chroma block, and the reference image can be the same. As another example, the intra-frame prediction process can be the same for both the luma and chroma decoders.

[0139] Video encoder 200 represents an example of a device configured to encode video data, the device including: a memory configured to store video data; and one or more processing units implemented in circuitry and configured to: determine a luma block co-located with the chroma block for a chroma block of an image; determine two or more reference chroma blocks based on the block vector of the luma block, the block vector pointing to a location within the image; generate prediction samples of the chroma block based on the two or more reference chroma blocks (e.g., via fusion); and perform block vector encoding on the chroma block based on the prediction samples.

[0140] The video encoder 200 also represents an example of a device configured to encode video data, the device comprising: a memory configured to store video data; and one or more processing units implemented in circuitry and configured to: determine one or more sub-blocks of a decoding unit (CU); determine at least one reference block based on at least one vector of at least one adjacent block of the CU; generate prediction samples of the CU based on the one or more sub-blocks and at least one reference block; and encode the CU based on the prediction samples.

[0141] Figure 3 This is a block diagram illustrating an example video decoder 300 that can perform the techniques of this disclosure. Figure 3 This disclosure is provided for illustrative purposes and not for limiting the techniques extensively illustrated and described herein. For illustrative purposes, this disclosure describes the video decoder 300 based on VVC and HEVC techniques. However, the techniques of this disclosure can be implemented by video decoding devices configured for other video decoding standards.

[0142] exist Figure 3 In the example, the video decoder 300 includes a decoded 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 DPB 314. Any 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 may be implemented in one or more processors or in processing circuitry. For example, units of the video decoder 300 may be implemented as one or more circuit or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Furthermore, the video decoder 300 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0143] The prediction processing unit 304 includes a motion compensation unit 316 and an intra-prediction unit 318. The prediction processing unit 304 may include additional units that perform predictions based on other prediction modes. As an example, the prediction processing unit 304 may include a palette unit, an intra-block copying 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.

[0144] When operating according to AV1, motion compensation unit 316 can be configured to decode video data blocks (e.g., both luma and chroma blocks) using translational motion compensation, affine motion compensation, OBMC, and / or composite inter-intra-frame prediction, as described above. Intra-frame prediction unit 318 can be configured to decode video data blocks (e.g., both luma and chroma blocks) using directional intra-frame prediction, non-directional intra-frame prediction, recursive filter intra-frame prediction, CFL, IBC, and / or palette mode, as described above.

[0145] CPB memory 320 may store video data to be decoded by components of video decoder 300, such as encoded video bitstreams. For example, it may be available 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 decoded picture, such as temporary data representing the output from various units of the video decoder 300. The DPB 314 typically stores a decoded picture, which the video decoder 300 may output, and / or uses as reference video data when decoding subsequent data or pictures of the encoded video bitstream. The CPB memory 320 and the DPB 314 may be formed from any of a variety of memory devices, such as DRAM (including SDRAM), MRAM, RRAM, or other types of memory devices. The CPB memory 320 and the DPB 314 may be provided by the same memory device or separate memory devices. In various examples, the CPB memory 320 may be on-chip with other components of the video decoder 300, or off-chip relative to those components.

[0146] Additionally or alternatively, in some examples, the video decoder 300 may be located from the memory 120 ( Figure 1Retrieving decoded video data. That is, memory 120 can utilize CPB memory 320 to store data as discussed above. Similarly, when some or all of the functionality of video decoder 300 is implemented in software to be executed by the processing circuitry of video decoder 300, memory 120 can store instructions to be executed by video decoder 300.

[0147] Examples Figure 3 The various units shown help to understand 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 2 Fixed-function circuits are circuits that provide specific functionality and are pre-defined for the operations they can perform. Programmable circuits are circuits that can be programmed to perform various tasks and provide flexible functionality for the operations they can perform. For example, a programmable circuit can execute software or firmware that causes the programmable circuit to operate in a manner defined by the instructions of the software or firmware. 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 in a unit may be different circuit blocks (fixed-function or programmable), and in some examples, one or more units in a unit may be integrated circuits.

[0148] 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.

[0149] Entropy decoding unit 302 can receive encoded video data from CPB and perform entropy decoding on the video data to reproduce 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 syntax elements extracted from the bitstream.

[0150] Typically, the video decoder 300 reconstructs the image block by block. 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").

[0151] 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 degree of quantization, and similarly, determine the degree of inverse quantization to be applied by inverse quantization unit 306. Inverse quantization unit 306 can, for example, perform a bit-by-bit 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.

[0152] After the inverse quantization unit 306 forms the transform coefficient block, the inverse transform processing unit 308 may apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, the inverse transform processing unit 308 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotation transform, an inverse direction transform, or another inverse transform to the transform coefficient block.

[0153] Furthermore, the prediction processing unit 304 generates a prediction block based on the prediction information syntax elements entropy-decoded by the entropy decoding unit 302. For example, if the prediction information syntax elements indicate that the current block is an inter-frame prediction, the motion compensation unit 316 can generate the prediction block. In this case, the prediction information syntax elements may indicate the reference picture from which the reference block is to be retrieved in the DPB 314, and a motion vector identifying the position of the reference block in the reference picture relative to the position of the current block in the current picture. The motion compensation unit 316 can typically be configured according to the parameters relative to the motion compensation unit 224 ( Figure 2 The method described is essentially the same as the method used to perform the inter-frame prediction process.

[0154] As another example, when the prediction information syntax element indicates that the current block is intra-predictive, the intra-predictive unit 318 can generate a prediction block according to the intra-predictive mode indicated by the prediction information syntax element. Similarly, the intra-predictive unit 318 can typically generate a prediction block according to the intra-predictive unit 226 ( Figure 2 The intra-prediction process is performed in a manner substantially similar to that described above. The intra-prediction unit 318 can retrieve data of neighboring samples of the current block from the DPB 314.

[0155] The reconstruction unit 310 can use the prediction block and the residual block to reconstruct the current block. For example, the reconstruction unit 310 can add samples from the residual block to the corresponding samples from the prediction block to reconstruct the current block.

[0156] Filter unit 312 may perform one or more filtering operations on the reconstructed block. For example, filter unit 312 may perform a deblocking operation to reduce block artifacts along the edges of the reconstructed block. The operation of filter unit 312 may not be performed in all examples.

[0157] The video decoder 300 can store reconstructed blocks in the DPB 314. For example, in an example where the operation of the filter unit 312 is not performed, the reconstruction unit 310 can store the reconstructed blocks in the DPB 314. In an example where the operation of the filter unit 312 is performed, the filter unit 312 can store the filtered reconstructed blocks in the DPB 314. As discussed above, the DPB 314 can provide reference information (such as samples of the current image for intra-frame prediction and samples of previously decoded images for subsequent motion compensation) to the prediction processing unit 304. Furthermore, the video decoder 300 can output decoded images (e.g., decoded video) from the DPB 314 for use in applications such as... Figure 1 The subsequent presentation on display devices such as display device 118.

[0158] Video decoder 300 represents an example of a device configured to encode video data, the device including: a memory configured to store video data; and one or more processing units implemented in circuitry and configured to: determine, for chroma blocks of an image, a luma block co-located with the chroma block; determine two or more reference chroma blocks based on block vectors of the luma blocks, the block vectors pointing to locations within the image; generate prediction samples of the chroma blocks based on the two or more reference chroma blocks (e.g., via fusion); and perform block vector decoding of the chroma blocks based on the prediction samples.

[0159] The video decoder 300 also represents an example of a device configured to encode video data, the device comprising: a memory configured to store video data; and one or more processing units implemented in circuitry and configured to: determine one or more sub-blocks of a decoding unit (CU); determine at least one reference block based on at least one vector of at least one block adjacent to the CU; generate prediction samples of the CU based on the one or more sub-blocks and at least one reference block; and decode the CU based on the prediction samples.

[0160] Figure 4 This is a flowchart illustrating an example method for encoding the current block according to the technology of this disclosure. The current block may be or may include the current CU. Although relative to video encoder 200 ( Figure 1 and Figure 2 This is described in the context of [the specific device described], but it should be understood that other devices can be configured to perform [the same actions]. Figure 4 Similar to the method.

[0161] In this example, the video encoder 200 initially predicts the current block (400). For example, the video encoder 200 may form a prediction block for the current block. According to the techniques described in this disclosure, the video encoder 200 can generate prediction samples of the prediction block by fusing two or more reference chroma blocks. The video encoder 200 may select two or more reference chroma blocks based on the block vector of a co-located luma block.

[0162] The video encoder 200 can then compute a residual block for the current block (402). To compute the residual block, the video encoder 200 can compute the difference between the original uncoded block and the predicted block for the current block. The video encoder 200 can then transform the residual block and quantize the transform coefficients of the residual block (404). Next, the video encoder 200 can scan the quantized transform coefficients of the residual block (406). During or after the scan, the video encoder 200 can entropy-encode the transform coefficients (408). For example, the video encoder 200 can use CAVLC or CABAC to encode the transform coefficients. The video encoder 200 can then output the entropy-encoded data of the block (410).

[0163] Figure 5 This is a flowchart illustrating an example method for decoding a current block of video data according to the technology of this disclosure. The current block may be or may include the current CU. Although relative to video decoder 300 ( Figure 1 and Figure 3 This is described in the context of [the specific device described], but it should be understood that other devices can be configured to perform [the same actions]. Figure 5 Similar to the method.

[0164] The video decoder 300 can receive entropy-coded data for the current block, such as entropy-coded prediction information and entropy-coded data for the transform coefficients of the residual block corresponding to the current block (500). The video decoder 300 can perform entropy decoding on the entropy-coded data to determine the prediction information for the current block and reproduce the transform coefficients of the residual block (502).

[0165] The video decoder 300 may, for example, use an intra-frame prediction mode or an inter-frame prediction mode indicated by prediction information for the current block to predict the current block (504) to compute a prediction block for the current block. According to the techniques described in this disclosure, the video decoder 300 may generate prediction samples of the prediction block by fusing two or more reference chroma blocks. The video decoder 300 may select two or more reference chroma blocks based on the block vector of a co-located luma block.

[0166] The video decoder 300 can then perform an inverse scan (506) on the reproduced transform coefficients to create a block of quantized transform coefficients. The video decoder 300 can then inverse quantize the transform coefficients and apply the inverse transform to the transform coefficients to produce a residual block (508). The video decoder 300 can then perform final decoding on the current block by combining the predicted block and the residual block (510).

[0167] Figure 10 This is a flowchart illustrating an example method of operation according to one or more examples described in this disclosure. For convenience, example techniques are described with respect to one or more memories and processing circuitry coupled to said one or more memories. One example of processing circuitry, such as for encoding chroma blocks, includes fixed-function and / or programmable circuitry of a video encoder 200. In such examples, the one or more memories may be memory 106, video data memory 230, DPB memory 218, or any other memory for storing video data. One example of processing circuitry, such as for decoding chroma blocks, includes fixed-function and / or programmable circuitry of a video decoder 300. In such examples, the one or more memories may be memory 120, CPB memory 320, DPB memory 314, or any other memory for storing video data.

[0168] For a chroma block of an image, the processing circuitry can be configured to determine the luminance block (1000) that co-addresses the chroma block. For example, refer to... Figure 6A In different partitioning schemes, the chroma component 602 and the luma component 600 can be divided in different ways. Furthermore, due to subsampling (e.g., 4:2:0 or 4:2:2 chroma mode), multiple luma blocks can co-address with a chroma block. A luma block co-addressed with a chroma block refers to a luma block and a chroma block that include sample values ​​used to generate video content for the same area on the display. However, because the chroma component 602 is downsampled relative to the luma component 600, multiple luma blocks co-address with a chroma block exist. For example, in... Figure 6A In the example, the CU 603 of chrominance component 602 (e.g., chrominance block 603) is co-located with at least the luma blocks TL, TR, C, BL and BR.

[0169] The processing circuit can determine two or more reference chroma blocks based on the block vector of the luma block, which points to location (1002) within the image. For example, the processing circuit can determine corresponding candidate reference chroma blocks based on the corresponding block vector of the luma block. As an example, the processing circuit can utilize... Figure 6A The block vectors of each of the luma blocks TL, TR, C, BL, and BR, and possibly after scaling, candidate block vectors, such as candidate block vectors for chroma block 900 (assuming... Figure 9900 chroma blocks and Figure 6A (Same as CU 603). The processing circuit can determine which blocks each candidate block vector in the candidate block vector points to. The block pointed to by each candidate block vector in the candidate block vector is the corresponding candidate reference chroma block.

[0170] The processing circuitry can determine the corresponding cost of a given candidate reference chroma block. As an example, to determine the corresponding cost, the processing circuitry can determine the matching amount between a first template adjacent to the corresponding candidate reference chroma block and a second template adjacent to the chroma block. For example, reference... Figure 9 The processing circuit can determine the cost of the TM-based reference chroma block 902A based on the SAD between templates 904 and 906, and determine the cost of the TM-based reference chroma block 902B based on the SAD between templates 908 and 906. SAD is one example of cost determination. Another example is using MSE to determine cost.

[0171] To determine two or more reference chroma blocks, the processing circuitry can select two or more candidate reference chroma blocks from among the candidate reference chroma blocks based on a corresponding cost. As an example, the processing circuitry can select N candidate reference chroma blocks associated with the lowest cost. As another example, the processing circuitry can construct a chroma block vector list based on a corresponding cost. For example, the processing circuitry can construct an original chroma block vector list based on the block vectors of co-located luma blocks, and may include the block vectors of adjacent chroma blocks. The processing circuitry can reorder the original chroma block vector list based on a corresponding cost (e.g., from lowest cost to highest cost) to construct a new chroma block vector list. To select two or more candidate reference chroma blocks from among the candidate reference chroma blocks, the processing circuitry can select two or more candidate reference chroma blocks from among the candidate reference chroma blocks based on the chroma block vector list. As an example, the video encoder 200 can signal an index in the chroma block vector list, and the video decoder 300 can receive that index.

[0172] The processing circuitry can be configured to fuse two or more reference chroma blocks to generate predicted samples of the chroma blocks (1004). As an example, the processing circuitry can average the two or more reference chroma blocks, or it can scale and sum the two or more reference chroma blocks. For example, suppose the reference chroma blocks are reference chroma block 902A and reference chroma block 902B. In one example, the processing circuitry can average (e.g., add and divide by two) the samples corresponding to the samples in reference chroma blocks 902A and 902B to generate predicted samples. As another example, the processing circuitry can scale each sample in reference chroma blocks 902A and 902B and sum the results of the corresponding samples to generate predicted samples.

[0173] As a further example, the processing circuitry can determine corresponding weights for two or more reference chroma blocks. For instance, the processing circuitry can determine a first weight for scaling samples of reference chroma block 902A and a second weight for scaling samples of reference chroma block 902B. For fusion, the processing circuitry can be configured to fuse two or more reference chroma blocks 902A and 902B based on their respective weights.

[0174] Various methods may exist for determining weights (e.g., a first weight and a second weight). As an example, the processing circuitry can determine the corresponding costs of two or more reference chroma blocks. For instance, the processing circuitry can determine a first cost based on the SAD or MSE between template 906 and template 904, and a second cost based on the SAD or MSE between template 908 and template 904.

[0175] The processing circuit can determine the corresponding weights based on the respective costs. For example, if the first cost is less than the second cost, the first weight applied to the samples of reference chroma block 902A is greater than the second weight applied to the samples of reference chroma block 902B, making the contribution of reference chroma block 902A greater in the predicted samples. If the second cost is less than the first cost, the second weight applied to the samples of reference chroma block 902B is greater than the first weight applied to the samples of reference chroma block 902A, making the contribution of reference chroma block 902B greater in the predicted samples.

[0176] As another example, the processing circuitry can determine the weighting factor derivation operation. The processing circuitry can determine the corresponding weights based on the weighting factor derivation operation. For example, video encoder 200 can signal information indicating whether the weights are derived based on TM (e.g., SAD), MSE, or fixed weights (e.g., where the fixed weights are predefined or signaled), and video decoder 300 can receive this information.

[0177] The processing circuitry can perform block vector encoding or decoding of the chroma block based on the prediction sample (1006). As an example, block vector encoding or decoding of the chroma block can be decoding the chroma block. To decode the chroma block, the processing circuitry can be configured to determine a residual value (e.g., via decoding) indicating the difference between the prediction sample and the chroma block. The processing circuitry can then add the residual value to the prediction sample to reconstruct the chroma block.

[0178] As another example, block vector encoding or decoding of a chroma block can be performed by encoding the chroma block. To encode a chroma block, the processing circuitry can determine a residual value indicating the difference between the predicted sample and the chroma block, and signal the information indicating the residual value.

[0179] The following numbered clauses illustrate one or more aspects of the devices and technologies described in this disclosure.

[0180] Clause 1. A method for encoding or decoding video data, the method comprising: for chroma blocks of an image, determining a luma block co-located with the chroma block; determining two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; generating a prediction sample of the chroma block based on the two or more reference chroma blocks; and performing block vector encoding or decoding of the chroma block based on the prediction sample.

[0181] Clause 2. The method according to Clause 1, wherein generating the prediction sample includes fusing the two or more reference chromaticity blocks.

[0182] Clause 3. The method according to Clause 2, wherein fusing the two or more reference chroma blocks includes averaging the two or more reference blocks; and / or scaling and summing the two or more reference blocks.

[0183] Clause 4. The method according to any one of Clauses 2 and 3, the method further comprising determining corresponding weights for the two or more reference chromaticity blocks, wherein fusion includes fusion of the two or more reference blocks based on the corresponding weights.

[0184] Clause 5. The method according to any one of Clauses 1 to 4, the method further comprising: determining a corresponding candidate reference chromaticity block based on each block vector in the block vectors of the luma block; and determining a corresponding cost of the corresponding candidate reference chromaticity block, wherein determining the two or more reference chromaticity blocks includes selecting two or more candidate reference chromaticity blocks from the candidate reference chromaticity blocks based on the corresponding cost.

[0185] Clause 6. The method according to Clause 5, wherein determining the corresponding cost includes determining the amount of matching between a first template adjacent to the corresponding candidate reference chroma block and a second template adjacent to the chroma block.

[0186] Clause 7. A method for encoding or decoding video data, the method comprising: determining one or more sub-blocks of a decoding unit (CU); determining at least one reference block based on at least one vector of at least one block adjacent to the CU; generating a prediction sample of the CU based on the one or more sub-blocks and the at least one reference block; and encoding or decoding the CU based on the prediction sample.

[0187] Clause 8. The method according to Clause 7, wherein the one or more sub-blocks of the CU are located at the boundary of the CU.

[0188] Clause 9. The method according to any one of Clauses 7 and 8, wherein generating a prediction sample comprises fusing the one or more sub-blocks and the at least one reference block.

[0189] Clause 10. The method according to Clause 9, wherein fusion includes averaging the one or more sub-blocks and the at least one reference block; and / or scaling and summing the one or more sub-blocks and the at least one reference block.

[0190] Clause 11. The method according to any one of Clauses 7 to 10, wherein the one or more sub-blocks are the top and left boundary sub-blocks of the CU.

[0191] Clause 12. The method according to any one of Clauses 7 to 11, wherein the CU is a luminance CU or a chromaticity CU.

[0192] Clause 13. An apparatus for encoding or decoding video data, the apparatus comprising: a memory configured to store the video data; and one or more processors embedded in circuitry and coupled to the memory, the one or more processors being configured to perform a method according to any one of Clauses 1 to 6 or 7 to 12.

[0193] Clause 14. The device according to Clause 13, the device further includes a display configured to display decoded video data.

[0194] Clause 15. The device pursuant to any one of Clauses 13 and 14, wherein the device comprises one or more of a camera, computer, mobile device, broadcast receiver device or set-top box.

[0195] Clause 16. The device according to any one of Clauses 13 to 15, wherein said device includes a video decoder.

[0196] Clause 17. The device according to any one of Clauses 13 to 15, wherein said device includes a video encoder.

[0197] Clause 18. A computer-readable storage medium having instructions stored thereon, which, when executed, cause one or more processors to perform the method according to any one of Clauses 1 to 6 or 7 to 12.

[0198] Clause 19. An apparatus for encoding or decoding video data, the apparatus comprising components for performing the method according to any one of Clauses 1 to 6 and 7 to 12.

[0199] Clause 1A. A method for encoding or decoding video data, the method comprising: for chroma blocks of an image, determining a luma block co-located with the chroma block; determining two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; fusing the two or more reference chroma blocks to generate a prediction sample of the chroma block; and performing block vector encoding or decoding of the chroma block based on the prediction sample.

[0200] Clause 2A. The method according to Clause 1A, wherein fusing the two or more reference chroma blocks includes performing at least one of the following: averaging the two or more reference chroma blocks; or scaling and summing the two or more reference chroma blocks.

[0201] Clause 3A. The method according to any one of Clauses 1A and 2A, the method further comprising determining corresponding weights for the two or more reference chroma blocks, wherein fusion includes fusion of the two or more reference chroma blocks based on the corresponding weights.

[0202] Clause 4A. The method according to Clause 3A, the method further comprising: determining the respective costs of the two or more reference chromaticity blocks, wherein determining the respective weights includes determining the respective weights based on the respective costs.

[0203] Clause 5A. The method according to any one of Clauses 3A or 4A, the method further comprising: determining a weighting factor derivation operation, wherein determining the corresponding weights includes determining the corresponding weights based on the weighting factor derivation operation.

[0204] Clause 6A. The method according to any one of Clauses 1A to 5A, the method further comprising: determining a corresponding candidate reference chromaticity block based on a corresponding block vector of the luma block; and determining a corresponding cost of the corresponding candidate reference chromaticity block, wherein determining the two or more reference chromaticity blocks includes selecting two or more candidate reference chromaticity blocks from the candidate reference chromaticity blocks based on the corresponding cost.

[0205] Clause 7A. The method according to Clause 6A, wherein determining the corresponding cost includes determining the amount of matching between a first template adjacent to the corresponding candidate reference chroma block and a second template adjacent to the chroma block.

[0206] Clause 8A. The method according to any one of Clauses 6A or 7A, the method further comprising constructing a chroma block vector list based on the respective cost, wherein selecting two or more candidate reference chroma blocks from the candidate reference chroma blocks includes selecting two or more candidate reference chroma blocks from the candidate reference chroma blocks based on the chroma block vector list.

[0207] Clause 9A. The method according to any one of Clauses 1A to 8A, wherein block vector encoding or decoding of the chroma block includes decoding the chroma block, and wherein decoding the chroma block includes: determining a residual value indicating a difference between the prediction sample and the chroma block; and adding the residual value to the prediction sample to reconstruct the chroma block.

[0208] Clause 10A. The method according to any one of Clauses 1A to 9A, wherein block vector encoding or decoding of the chroma block includes encoding the chroma block, and wherein encoding the chroma block includes: determining a residual value indicating the difference between the predicted sample and the chroma block; and signaling information indicating the residual value.

[0209] Clause 11A. An apparatus for encoding or decoding video data, the apparatus comprising: one or more memories configured to store the video data; and processing circuitry coupled to the one or more memories and configured to: for chroma blocks of an image, determine a luma block co-located with the chroma block; determine two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; fuse the two or more reference chroma blocks to generate a prediction sample of the chroma block; and perform block vector encoding or decoding of the chroma block based on the prediction sample.

[0210] Clause 12A. The apparatus according to Clause 11A, wherein, in order to fuse the two or more reference chroma blocks, the processing circuitry is configured to perform at least one of the following: averaging the two or more reference chroma blocks; or scaling and summing the two or more reference chroma blocks.

[0211] Clause 13A. The apparatus of any one of Clauses 11A and 12A, wherein the processing circuitry is configured to: determine corresponding weights of the two or more reference chromaticity blocks, wherein, in order to perform fusion, the processing circuitry is configured to fuse the two or more reference chromaticity blocks based on the corresponding weights.

[0212] Clause 14A. The apparatus of Clause 13A, wherein the processing circuitry is configured to determine the respective costs of the two or more reference chromaticity blocks, wherein, in order to determine the respective weights, the processing circuitry is configured to determine the respective weights based on the respective costs.

[0213] Clause 15A pursuant to the apparatus described in Clauses 13A and 14A, wherein the processing circuitry is configured to: determine a weighting factor derivation operation, wherein, in order to determine the corresponding weights, the processing circuitry is configured to determine the corresponding weights based on the weighting factor derivation operation.

[0214] Clause 16A. The apparatus of Clauses 11A to 15A, wherein the processing circuitry is configured to: determine a corresponding candidate reference chromaticity block based on a corresponding block vector of the luminance block; and determine a corresponding cost of the corresponding candidate reference chromaticity block, wherein in order to determine the two or more reference chromaticity blocks, the processing circuitry is configured to select two or more candidate reference chromaticity blocks from the candidate reference chromaticity blocks based on the corresponding cost.

[0215] Clause 17A. The apparatus according to Clause 16A, wherein, in order to determine the corresponding cost, the processing circuitry is configured to determine the amount of matching between a first template adjacent to the corresponding candidate reference chroma block and a second template adjacent to the chroma block.

[0216] Clause 18A. The apparatus of Clauses 16A and 17A, wherein the processing circuitry is configured to: construct a chroma block vector list based on the corresponding cost, wherein in order to select two or more candidate reference chroma blocks from the candidate reference chroma blocks, the processing circuitry is configured to select two or more candidate reference chroma blocks from the candidate reference chroma block vector list.

[0217] Clause 19A. The apparatus of any one of Clauses 11A to 18A, wherein the processing circuitry is configured to: determine a residual value indicating a difference between the predicted sample and the chroma block; and perform at least one of the following: adding the residual value to the predicted sample to reconstruct the chroma block; or signaling information indicating the residual value.

[0218] Clause 20A. A computer-readable storage medium having instructions stored thereon, the instructions, when executed, causing one or more processors to: determine, for a chroma block of an image, a luma block co-located with the chroma block; determine two or more reference chroma blocks based on a block vector of the luma block, the block vector pointing to a location within the image; fuse the two or more reference chroma blocks to generate a prediction sample of the chroma block; and perform block vector encoding or decoding of the chroma block based on the prediction sample.

[0219] It should be recognized that, based on the examples, certain actions 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 actions or events described are necessary for implementing the technique). Furthermore, in some examples, actions or events may be performed concurrently (e.g., through multithreading, interrupt handling, or multiple processors) rather than sequentially.

[0220] In one or more examples, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on a computer-readable medium or transmitted via a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include a computer-readable storage medium (which corresponds to a tangible medium such as a data storage medium) or a communication medium, 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 retrieve instructions, code, and / or data structures for implementing the techniques described in this disclosure. Computer program products may include computer-readable media.

[0221] By way of example, and not limitation, such computer-readable storage media may include one or more of 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 capable of storing desired program code in the form of instructions or data structures and accessible by a computer. Furthermore, any connection is appropriately referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology (such as infrared, radio, and microwave), then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is 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 instead refer to non-transient tangible storage media. As used herein, disks and optical discs include compact optical discs (CDs), laser optical discs, optical discs, digital versatile optical discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically, while optical discs use lasers to reproduce data optically. Combinations of these should also be included within the scope of computer-readable media.

[0222] Instructions can be executed by one or more processors, such as one or more DSPs, general-purpose microprocessors, ASICs, FPGAs, or other equivalent integrated or discrete logic circuits. Therefore, as used herein, the terms "processor" and "processing circuit" can refer to any of the foregoing structures or any other structure suitable for implementing the techniques described herein. Furthermore, 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. Moreover, these techniques can be fully implemented in one or more circuit or logic elements.

[0223] The techniques disclosed herein can be implemented in a wide variety of devices or apparatuses, including wireless mobile phones, integrated circuits (ICs), or IC sets (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 techniques, but implementation by different hardware units is not necessarily required. Specifically, as described above, various units may be combined in a codec hardware unit, or various units may be provided by a collection of interoperable hardware units (including one or more processors as described above) combined with appropriate software and / or firmware.

[0224] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. A method for encoding or decoding video data, the method comprising: For each chroma block in an image, determine the luminance block that shares the same address with the chroma block; Two or more reference chromaticity blocks are determined based on the block vector of the luminance block, the block vector pointing to a position within the image; The two or more reference chromaticity blocks are fused to generate a predicted sample of the chromaticity block; as well as The chroma blocks are then encoded or decoded based on the predicted samples.

2. The method of claim 1, wherein fusing the two or more reference chromaticity blocks comprises performing at least one of the following: Averaging the two or more reference chromaticity blocks; or The two or more reference chromaticity blocks are scaled and summed.

3. The method according to claim 1, further comprising: Determine the corresponding weights of the two or more reference chromaticity blocks. The fusion process includes fusing the two or more reference chromaticity blocks based on the corresponding weights.

4. The method according to claim 3, further comprising: Determine the corresponding cost of the two or more reference chromaticity blocks. Determining the corresponding weights includes determining the corresponding weights based on the corresponding costs.

5. The method according to claim 3, further comprising: Determine the weighting factor derivation operation. Determining the corresponding weights includes determining the corresponding weights based on the weighting factor derivation operation.

6. The method according to claim 1, further comprising: The corresponding candidate reference chromaticity block is determined based on the corresponding block vector of the luminance block; as well as Determine the corresponding cost of the respective candidate reference chromaticity blocks. Determining the two or more reference chromaticity blocks includes selecting two or more candidate reference chromaticity blocks from among the candidate reference chromaticity blocks based on the corresponding cost.

7. The method of claim 6, wherein determining the corresponding cost includes determining the amount of matching between a first template adjacent to the corresponding candidate reference chroma block and a second template adjacent to the chroma block.

8. The method according to claim 6, further comprising: A list of chroma block vectors is constructed based on the corresponding costs. Selecting two or more candidate reference chromaticity blocks from the candidate reference chromaticity blocks includes selecting two or more candidate reference chromaticity blocks from the candidate reference chromaticity blocks based on the chromaticity block vector list.

9. The method of claim 1, wherein block vector encoding or decoding of the chroma block includes decoding the chroma block, and wherein decoding the chroma block includes: Determine the residual value that indicates the difference between the predicted sample and the color patch; as well as The residual value is added to the predicted sample to reconstruct the chroma block.

10. The method of claim 1, wherein block vector encoding or decoding of the chroma block comprises encoding the chroma block, and wherein encoding the chroma block comprises: Determine the residual value that indicates the difference between the predicted sample and the color patch; as well as Send a signal to indicate the information indicating the residual value.

11. An apparatus for encoding or decoding video data, the apparatus comprising: One or more memories, the one or more memories being configured to store the video data; and Processing circuitry, coupled to the one or more memories and configured to: For each chroma block in an image, determine the luminance block that shares the same address with the chroma block; Two or more reference chromaticity blocks are determined based on the block vector of the luminance block, the block vector pointing to a position within the image; The two or more reference chromaticity blocks are fused to generate a predicted sample of the chromaticity block; as well as The chroma blocks are then encoded or decoded based on the predicted samples.

12. The apparatus of claim 11, wherein, in order to fuse the two or more reference chromaticity blocks, the processing circuitry is configured to perform at least one of the following: Averaging the two or more reference chromaticity blocks; or The two or more reference chromaticity blocks are scaled and summed.

13. The device of claim 11, wherein the processing circuit is configured to: Determine the corresponding weights of the two or more reference chromaticity blocks. In order to perform the fusion, the processing circuit is configured to fuse the two or more reference chromaticity blocks based on the corresponding weights.

14. The device of claim 13, wherein the processing circuit is configured to: Determine the corresponding cost of the two or more reference chromaticity blocks. In order to determine the corresponding weight, the processing circuit is configured to determine the corresponding weight based on the corresponding cost.

15. The apparatus of claim 13, wherein the processing circuit is configured to: Determine the weighting factor derivation operation. In order to determine the corresponding weights, the processing circuit is configured to determine the corresponding weights based on the weighting factor derivation operation.

16. The apparatus of claim 11, wherein the processing circuit is configured to: Based on the corresponding block vector of the luminance block, determine the corresponding candidate reference chrominance block; and Determine the corresponding cost of the respective candidate reference chromaticity blocks. In order to determine the two or more reference chromaticity blocks, the processing circuit is configured to select two or more candidate reference chromaticity blocks from the candidate reference chromaticity blocks based on the corresponding cost.

17. The apparatus of claim 16, wherein, in order to determine the corresponding cost, the processing circuitry is configured to determine the matching amount between a first template adjacent to the corresponding candidate reference chroma block and a second template adjacent to the chroma block.

18. The device of claim 16, wherein the processing circuit is configured to: A list of chroma block vectors is constructed based on the corresponding costs. In order to select two or more candidate reference chroma blocks from the candidate reference chroma blocks, the processing circuit is configured to select two or more candidate reference chroma blocks from the candidate reference chroma blocks based on the chroma block vector list.

19. The apparatus of claim 11, wherein the processing circuit is configured to: Determine the residual value indicating the difference between the predicted sample and the chromaticity patch; and Perform at least one of the following: Add the residual value to the predicted sample to reconstruct the chroma block; or Send a signal to indicate the information indicating the residual value.

20. A computer-readable storage medium having instructions stored thereon, the instructions causing one or more processors to: For each chroma block in an image, determine the luminance block that shares the same address with the chroma block; Two or more reference chromaticity blocks are determined based on the block vector of the luminance block, the block vector pointing to a position within the image; The two or more reference chromaticity blocks are fused to generate a predicted sample of the chromaticity block; as well as The chroma blocks are then encoded or decoded based on the predicted samples.

Images