Video encoding and decoding method and device and storage medium

Abstract

The invention provides a video decoding method and device and a storage medium. A video decoding method includes receiving an encoded video bitstream including a current picture. The method includes determining a predetermined condition associated with signaling data included in the encoded video bitstream. The method includes determining a size of an index for a candidate list for vector predictors included in the signaling data based on a number of merge mode candidates and a number of intra block copy (IBC) candidates according to the predetermined condition. The method includes constructing the candidate list using vector predictors. The method includes retrieving vector predictors in the candidate list according to the index, where the value of the index does not exceed the size of the determined index. The method includes decoding the current block according to the retrieved vector predictor.

Description

[0001] Incorporation by Reference

[0002] The present disclosure claims priority to U.S. Application No. 16 / 863,661, filed on April 30, 2020, for “Method and Apparatus for Signaling a Candidate List Size of a Predictor for Intra Image Block Compensation,” which claims priority to U.S. Provisional Application No. 62 / 904,307, filed on September 23, 2019, for “Prediction Method for Intra Image Block Compensation,” and U.S. Provisional Application No. 62 / 873,044, filed on July 11, 2019, for “Signaling a Candidate List Size of a Predictor for Intra Image Block Compensation.” The entire disclosure of the prior application is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure describes embodiments related to video coding. Background Art

[0004] The background description provided herein is intended to present the background of the present application as a whole. The extent to which the work of the presently named inventors described in the background section and various aspects of this specification is performed does not indicate that it is prior art at the time of filing this application, and it is never explicitly or implicitly admitted that it is prior art for this application.

[0005] Video encoding and decoding are made possible by inter-picture prediction techniques with motion compensation. An uncompressed digital video may include a series of pictures, each picture having a spatial dimension of, for example, 1920×1080 luminance samples and associated chrominance samples. The series of pictures has a fixed or variable picture rate (also informally referred to as a frame rate), for example, 60 pictures per second or 60Hz. Uncompressed video has very large bitrate requirements. For example, 1080p60 4:2:0 video (1920x1080 luminance sample resolution, 60Hz frame rate) with 8 bits per sample requires close to 1.5Gbit / s bandwidth. One hour of such video requires more than 600GB of storage space.

[0006] One goal of video encoding and decoding is to reduce redundant information in the input video signal through compression. Video compression can help reduce the bandwidth or storage space requirements mentioned above, in some cases by two or more orders of magnitude. Both lossless and lossy compression, as well as combinations of the two, can be used. Lossless compression refers to techniques that reconstruct an exact replica of the original signal from the compressed original signal. When lossy compression is used, the reconstructed signal may not be exactly the same as the original signal, but the distortion between the original and the reconstructed signal is small enough that the reconstructed signal can be used for the intended application. Lossy compression is widely used in video. The amount of distortion allowed depends on the application. For example, users of some consumer streaming applications may tolerate higher distortion than users of television applications. The achievable compression ratio reflects that higher allowed / tolerable distortion results in higher compression ratios.

[0007] Motion compensation may be a lossy compression technique and may involve a technique where a block of sample data from a previously reconstructed picture or part of a reconstructed picture (reference picture) is used for prediction of a newly reconstructed picture or part of a picture after being spatially shifted in the direction indicated by a motion vector (hereinafter MV). In some cases, the reference picture may be the same as the picture currently being reconstructed. The MV may have two dimensions, X and Y, or three dimensions, where the third dimension indicates the reference picture in use (the latter may indirectly be the temporal dimension).

[0008] In some video compression techniques, the MV applied to a region of sample data can be predicted based on other MVs, such as those MVs associated with another region of sample data that is spatially adjacent to the region being reconstructed and that precede the MV in decoding order. Doing so can greatly reduce the amount of data required to encode the MV, thereby eliminating redundant information and increasing the amount of compression. MV prediction can be done effectively, for example, when encoding an input video signal derived from a camera (called natural video), there is a statistical probability that regions larger than the region to which a single MV applies will move in a similar direction, so in some cases, similar motion vectors derived from MVs of neighboring regions can be used for prediction. This results in the MV found for a given region being similar or identical to the MV predicted from the surrounding MVs, and after entropy coding, it can be represented with fewer bits than the number of bits used when the MV is directly encoded. In some cases, MV prediction can be an example of lossless compression of a signal (i.e., MV) derived from the original signal (i.e., sample stream). In other cases, MV prediction itself may be lossy, for example due to rounding errors when calculating predicted values ​​based on several surrounding MVs.

[0009] H.265 / HEVC (ITU-T Rec. H.265, "High Efficiency Video Coding", December 2016) describes various MV prediction mechanisms. Among the various MV prediction mechanisms provided by H.265, this article describes a technique hereinafter referred to as "spatial merging".

[0010] 1 , the current block (101) includes samples found by the encoder during a motion search process, which can be predicted based on a previous block that has been spatially moved by the same size. The MV is not encoded directly, but is derived from metadata associated with one or more reference pictures, such as the most recent (in decoding order) reference picture, using an MV associated with any of the five surrounding samples. The five surrounding samples are represented by A0, A1 and B0, B1, B2 (102 to 106 respectively). In H.265, MV prediction can use the prediction value of the same reference picture being used by the adjacent blocks. The order of forming the candidate list can be A0→B0→B1→A1→B2. Summary of the invention

[0011] According to an exemplary embodiment, a video decoding method includes: receiving an encoded video bitstream including a current picture. The method includes: determining a predetermined condition associated with signaling data included in the encoded video bitstream. The method includes: determining the size of an index of a candidate list for a vector prediction value included in the signaling data based on the number of merge mode candidates and the number of intra-block copy IBC candidates according to the predetermined condition. The method includes: constructing the candidate list using the vector prediction value. The method includes: retrieving the vector prediction value in the candidate list according to the index, wherein the value of the index does not exceed the size of the determined index. The method includes: decoding the current block according to the retrieved vector prediction value.

[0012] According to an exemplary embodiment, a video decoding method includes: receiving an encoded video bitstream including a current picture. The method also includes: retrieving signaling data of the encoded video bitstream for a current block. The method also includes: determining whether the signaling data retrieved for the current block includes a maximum number of merge candidates. The method also includes: setting a maximum number of intra-block copy (IBC) candidates based on whether the maximum number of merge candidates is included in the signaling data of the current block.

[0013] According to an exemplary embodiment, a video decoding device for video decoding includes a processing circuit for receiving an encoded video bitstream including a current picture. The processing circuit is also used to determine a predetermined condition associated with signaling data included in the encoded video bitstream. The processing circuit is also used to determine the size of an index of a candidate list for vector prediction values ​​included in the signaling data based on the number of merge mode candidates and the number of intra-block copy IBC candidates according to the predetermined condition. The processing circuit is also used to construct the candidate list using the vector prediction value; according to the index, retrieve the vector prediction value in the candidate list, wherein the value of the index does not exceed the size of the determined index. The processing circuit is also used to decode the current block according to the retrieved vector prediction value.

[0014] According to an exemplary embodiment, a video decoder device for video decoding includes a processing circuit for receiving an encoded video bitstream including a current picture. The processing circuit is also used to retrieve signaling data of the encoded video bitstream for a current block. The processing circuit is also used to determine whether the signaling data retrieved for the current block includes a maximum number of merge candidates. The processing circuit is also used to set a maximum number of intra-block copy (IBC) candidates based on whether the maximum number of merge candidates is included in the signaling data of the current block.

[0015] A non-volatile computer-readable medium storing instructions, when the instructions are executed by a processor in a video decoder, causes the processor to perform a method, the method comprising receiving an encoded video bitstream including a current picture. The method comprises determining a predetermined condition associated with signaling data included in the encoded video bitstream. The method comprises determining the size of an index of a candidate list for a vector prediction value included in the signaling data based on the number of merge mode candidates and the number of intra-block copy (IBC) candidates according to the predetermined condition. The method comprises constructing the candidate list using the vector prediction value. The method comprises retrieving the vector prediction value in the candidate list according to the index, wherein the value of the index does not exceed the size of the determined index. The method comprises decoding the current block according to the retrieved vector prediction value.

[0016] A non-volatile computer-readable medium storing instructions, which, when executed by a processor in a video decoder, causes the processor to perform a method, the method comprising receiving an encoded video bitstream including a current picture. The method further comprises retrieving signaling data of the encoded video bitstream for a current block. The method further comprises determining whether the signaling data retrieved for the current block includes a maximum number of merge candidates. The method further comprises setting a maximum number of intra-block copy (IBC) candidates based on the determination of whether the signaling data of the current block includes the maximum number of merge candidates. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, properties and various advantages of the disclosed subject matter will become more apparent from the following detailed description and accompanying drawings, in which:

[0018] FIG. 1 is a schematic diagram of a current block and its surrounding spatial merging candidates in an example.

[0019] Figure 2 is a schematic diagram of a simplified block diagram of a communication system according to one embodiment.

[0020] Figure 3 is a schematic diagram of a simplified block diagram of a communication system according to another embodiment.

[0021] Figure 4 is a schematic diagram of a simplified block diagram of a decoder according to one embodiment.

[0022] Figure 5 is a schematic diagram of a simplified block diagram of an encoder according to one embodiment.

[0023] Figure 6 A block diagram of an encoder according to another embodiment is shown.

[0024] Figure 7 A block diagram of a decoder according to another embodiment is shown.

[0025] Figure 8 is a schematic diagram of intra-frame image block compensation according to an embodiment.

[0026] Figures 9A-9D It is a schematic diagram of intra-frame image block compensation with a Coding Tree Unit (CTU) size search range according to one embodiment.

[0027] Figures 10A-10D is a schematic diagram of how to update a buffer according to an embodiment.

[0028] Fig.11Ais a diagram of a debit flow chart of a history-based MV prediction (HMVP) buffer.

[0029] Fig. 11B is a schematic diagram of updating the HMVP buffer.

[0030] Fig.12 is a diagram of an example decoding process according to an embodiment.

[0031] Fig.13 is a diagram of an example decoding process according to an embodiment.

[0032] Fig.14 is a schematic diagram of a computer system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] Figure 2 2 is a simplified block diagram of a communication system (200) according to an embodiment disclosed in the present application. The communication system (200) includes a plurality of terminal devices, which can communicate with each other through, for example, a network (250). For example, the communication system (200) includes a first terminal device (210) and a second terminal device (220) interconnected through the network (250). Figure 2 In an embodiment of the present invention, the first terminal device (210) and the second terminal device (220) perform unidirectional data transmission. For example, the first terminal device (210) may encode video data (e.g., a video picture stream collected by the terminal device (210)) for transmission to the second terminal device (220) via the network (250). The encoded video data is transmitted in the form of one or more encoded video bit streams. The second terminal device (220) may receive the encoded video data from the network (250), decode the encoded video data to restore the video data, and display the video picture based on the restored video data. Unidirectional data transmission is more common in applications such as media services.

[0034] In another embodiment, the communication system (200) includes a third terminal device (230) and a fourth terminal device (240) that perform bidirectional transmission of encoded video data, which can occur, for example, during a video conference. For bidirectional data transmission, each of the third terminal device (230) and the fourth terminal device (240) can encode video data (e.g., a video picture stream collected by the terminal device) to transmit to the other terminal device of the third terminal device (230) and the fourth terminal device (240) through a network (250). Each of the third terminal device (230) and the fourth terminal device (240) can also receive the encoded video data transmitted by the other terminal device of the third terminal device (230) and the fourth terminal device (240), and can decode the encoded video data to restore the video data, and can display the video picture on an accessible display device based on the restored video data.

[0035] exist Figure 2 In the embodiment of the present invention, the first terminal device (210), the second terminal device (220), the third terminal device (230) and the fourth terminal device (240) may be servers, personal computers and smart phones, but the principles disclosed in the present application may not be limited thereto. The embodiments disclosed in the present application are applicable to laptop computers, tablet computers, media players and / or dedicated video conferencing equipment. The network (250) represents any number of networks that transmit encoded video data between the first terminal device (210), the second terminal device (220), the third terminal device (230) and the fourth terminal device (240), including, for example, wired (wired) and / or wireless communication networks. The communication network (250) may exchange data in circuit switching and / or packet switching channels. The network may include a telecommunications network, a local area network, a wide area network and / or the Internet. For the purpose of the present application, unless explained below, the architecture and topology of the network (250) may be irrelevant to the operation disclosed in the present application.

[0036] As an example, Figure 3 The video encoder and video decoder are shown in a streaming environment. The subject matter disclosed in this application is equally applicable to other video-enabled applications, including, for example, video conferencing, digital TV, storing compressed video on digital media including CDs, DVDs, memory sticks, etc.

[0037] The streaming system may include an acquisition subsystem (313), which may include a video source (301) such as a digital camera, which creates an uncompressed video picture stream (302). In an embodiment, the video picture stream (302) includes samples captured by the digital camera. Compared to the encoded video data (304) (or the encoded video bitstream), the video picture stream (302) is depicted as a thick line to emphasize the high data volume of the video picture stream, and the video picture stream (302) can be processed by an electronic device (320), which includes a video encoder (303) coupled to the video source (301). The video encoder (303) may include hardware, software, or a combination of hardware and software to implement or implement various aspects of the disclosed subject matter as described in more detail below. Compared to the video picture stream (302), the encoded video data (304) (or the encoded video bitstream (304)) is depicted as a thin line to emphasize the lower amount of data of the encoded video data (304) (or the encoded video bitstream (304)), which can be stored on the streaming server (305) for future use. One or more streaming client subsystems, such as Figure 3 The client subsystem (306) and the client subsystem (308) in the streaming server (305) can access the streaming server (305) to retrieve the copy (307) and the copy (309) of the encoded video data (304). The client subsystem (306) may include, for example, a video decoder (310) in the electronic device (330). The video decoder (310) decodes the incoming copy (307) of the encoded video data and generates an output video picture stream (311) that can be presented on a display (312) (e.g., a display screen) or another presentation device (not depicted). In some streaming systems, the encoded video data (304), the video data (307), and the video data (309) (e.g., a video bitstream) can be encoded according to certain video encoding / compression standards. Examples of these standards include ITU-T H.265. In an embodiment, the video coding standard under development is informally referred to as Versatile Video Coding (VVC), and the present application can be used in the context of the VVC standard.

[0038] It should be noted that the electronic device (320) and the electronic device (330) may include other components (not shown). For example, the electronic device (320) may include a video decoder (not shown), and the electronic device (330) may also include a video encoder (not shown).

[0039] Figure 44 is a block diagram of a video decoder (410) according to an embodiment disclosed in the present application. The video decoder (410) may be provided in an electronic device (430). The electronic device (430) may include a receiver (431) (e.g., a receiving circuit). The video decoder (410) may be used to replace Figure 3 A video decoder (310) of an embodiment.

[0040] The receiver (431) may receive one or more encoded video sequences to be decoded by the video decoder (410); in the same or another embodiment, one encoded video sequence is received at a time, wherein the decoding of each encoded video sequence is independent of the other encoded video sequences. The encoded video sequence may be received from a channel (401), which may be a hardware / software link to a storage device storing the encoded video data. The receiver (431) may receive the encoded video data as well as other data, such as encoded audio data and / or auxiliary data streams that may be forwarded to their respective consuming entities (not shown). The receiver (431) may separate the encoded video sequence from the other data. To prevent network jitter, a buffer memory (415) may be coupled between the receiver (431) and the entropy decoder / parser (420) (hereinafter referred to as "parser (420)"). In some applications, the buffer memory (415) is part of the video decoder (410). In other cases, the buffer memory (415) may be provided external to the video decoder (410) (not shown). In other cases, a buffer memory (not shown) is provided outside the video decoder (410) to prevent network jitter, for example, and another buffer memory (415) may be configured inside the video decoder (410) to handle broadcast timing, for example. When the receiver (431) receives data from a storage / forward device with sufficient bandwidth and controllability or from an isochronous network, it may not be necessary to configure the buffer memory (415), or the buffer memory may be made smaller. Of course, in order to use on a service packet network such as the Internet, a buffer memory (415) may also be required, and the buffer memory may be relatively large and have an adaptive size, and may be at least partially implemented in an operating system or a similar element (not shown) outside the video decoder (410).

[0041] The video decoder (410) may include a parser (420) to reconstruct symbols (421) from the encoded video sequence. The types of symbols include information used to manage the operation of the video decoder (410) and potential information used to control a display device such as a display device (412) (e.g., a display screen) that is not part of the electronic device (430) but can be coupled to the electronic device (430), such as Figure 4As shown in . The control information for the display device may be a parameter set fragment (not indicated) of Supplemental Enhancement Information (SEI message) or Video Usability Information (VUI). The parser (420) may parse / entropy decode the received coded video sequence. The encoding of the coded video sequence may be performed according to a video coding technique or standard, and may follow various principles, including variable length coding, Huffman coding, arithmetic coding with or without context sensitivity, and the like. The parser (420) may extract a subgroup parameter set of at least one subgroup of the subgroups of pixels in the video decoder from the coded video sequence based on at least one parameter corresponding to the group. The subgroup may include a Group of Pictures (GOP), a picture, a tile, a slice, a macroblock, a Coding Unit (CU), a block, a Transform Unit (TU), a Prediction Unit (PU), and the like. The parser (420) may also extract information from the encoded video sequence, such as transform coefficients, quantizer parameter values, motion vectors, and so on.

[0042] The parser (420) may perform entropy decoding / parsing operations on the video sequence received from the buffer memory (415), thereby creating symbols (421).

[0043] Depending on the type of coded video picture or portion of coded video picture (e.g., inter- and intra-pictures, inter- and intra-blocks) and other factors, the reconstruction of the symbol (421) may involve multiple different units. Which units are involved and how they are involved may be controlled by subgroup control information parsed by the parser (420) from the coded video sequence. For the sake of brevity, such subgroup control information flow between the parser (420) and the multiple units below is not described.

[0044] In addition to the functional blocks already mentioned, the video decoder (410) can be conceptually subdivided into several functional units as described below. In a practical embodiment operating under commercial constraints, many of these units interact closely with each other and can be integrated with each other. However, for the purpose of describing the disclosed subject matter, the conceptual subdivision into the following functional units is appropriate.

[0045] The first unit is a sealer / inverse transform unit (451). The sealer / inverse transform unit (451) receives quantized transform coefficients as symbols (421) from the parser (420) and control information, including which transform method to use, block size, quantization factor, quantization scaling matrix, etc. The sealer / inverse transform unit (451) can output a block including sample values, which can be input into an aggregator (455).

[0046] In some cases, the output samples of the scaler / inverse transform unit (451) may belong to an intra-coded block; that is, a block that does not use predictive information from a previously reconstructed picture, but may use predictive information from a previously reconstructed portion of the current picture. Such predictive information may be provided by an intra-picture prediction unit (452). In some cases, the intra-picture prediction unit (452) generates surrounding blocks of the same size and shape as the block being reconstructed using reconstructed information extracted from a current picture buffer (458). For example, the current picture buffer (458) buffers a partially reconstructed current picture and / or a fully reconstructed current picture. In some cases, the aggregator (455) adds the prediction information generated by the intra-prediction unit (452) to the output sample information provided by the scaler / inverse transform unit (451) on a per-sample basis.

[0047] In other cases, the output samples of the scaler / inverse transform unit (451) may belong to an inter-frame coded and potentially motion compensated block. In this case, the motion compensated prediction unit (453) may access the reference picture memory (457) to extract samples for prediction. After the extracted samples are motion compensated according to the symbols (421), these samples may be added to the output of the scaler / inverse transform unit (451) (in this case referred to as residual samples or residual signals) by the aggregator (455) to generate output sample information. The acquisition of the predicted samples by the motion compensated prediction unit (453) from the address in the reference picture memory (457) may be controlled by a motion vector, and the motion vector is provided to the motion compensated prediction unit (453) in the form of the symbols (421), for example, including X, Y and reference picture components. Motion compensation may also include interpolation of sample values ​​extracted from the reference picture memory (457) when using sub-sample accurate motion vectors, motion vector prediction mechanisms, and the like.

[0048] The output samples of the aggregator (455) may be employed by various loop filtering techniques in a loop filter unit (456). The video compression techniques may include in-loop filter techniques controlled by parameters included in the encoded video sequence (also referred to as the encoded video bitstream) and available to the loop filter unit (456) as symbols (421) from the parser (420). However, in other embodiments, the video compression techniques may also be responsive to meta-information obtained during decoding of a previous (in decoding order) portion of an encoded picture or encoded video sequence, as well as to previously reconstructed and loop filtered sample values.

[0049] The output of the loop filter unit (456) may be a sample stream that may be output to a display device (412) and stored in a reference picture memory (457) for subsequent inter-picture prediction.

[0050] Once fully reconstructed, certain coded pictures may be used as reference pictures for future prediction. For example, once the coded picture corresponding to the current picture is fully reconstructed, and the coded picture is identified as a reference picture (e.g., by the parser (420)), the current picture buffer (458) may become part of the reference picture memory (457), and a new current picture buffer may be reallocated before starting to reconstruct a subsequent coded picture.

[0051] The video decoder (410) may perform decoding operations according to a predetermined video compression technique, such as in the ITU-T H.265 standard. The encoded video sequence may conform to the syntax specified by the video compression technique or standard used in the sense that the encoded video sequence follows the syntax of the video compression technique or standard and the profile recorded in the video compression technique or standard. Specifically, the profile may select certain tools from all the tools available in the video compression technique or standard as the only tools available for use under the profile. For compliance, the complexity of the encoded video sequence is also required to be within the range defined by the hierarchy of the video compression technique or standard. In some cases, the hierarchy limits the maximum picture size, the maximum frame rate, the maximum reconstruction sampling rate (measured in, for example, mega samples per second), the maximum reference picture size, etc. In some cases, the limits set by the hierarchy may be further limited by the Hypothetical Reference Decoder (HRD) specification and metadata of the HRD buffer management signaled in the encoded video sequence.

[0052] In an embodiment, the receiver (431) may receive additional (redundant) data along with the encoded video. The additional data may be part of the encoded video sequence. The additional data may be used by the video decoder (410) to properly decode the data and / or more accurately reconstruct the original video data. The additional data may be in the form of, for example, temporal, spatial or signal-to-noise ratio (SNR) enhancement layers, redundant slices, redundant pictures, forward error correction codes, etc.

[0053] Figure 5 1 is a block diagram of a video encoder (503) according to an embodiment disclosed in the present application. The video encoder (503) is provided in an electronic device (520). The electronic device (520) includes a transmitter (540) (e.g., a transmission circuit). The video encoder (503) can be used to replace Figure 3 A video encoder (303) in an embodiment.

[0054] The video encoder (503) can be used to obtain the video source (501) (not Figure 5 In another embodiment, the video source (501) is a part of the electronic device (520) to receive video samples, and the video source can collect video images to be encoded by the video encoder (503). In another embodiment, the video source (501) is a part of the electronic device (520).

[0055] The video source (501) may provide a source video sequence in the form of a digital video sample stream to be encoded by the video encoder (503), wherein the digital video sample stream may have any suitable bit depth (e.g., 8-bit, 10-bit, 12-bit, ...), any color space (e.g., BT.601 Y CrCB, RGB, ...), and any suitable sampling structure (e.g., Y CrCb 4:2:0, Y CrCb 4:4:4). In a media service system, the video source (501) may be a storage device storing previously prepared videos. In a video conferencing system, the video source (501) may be a camera that captures local image information as a video sequence. The video data may be provided as a plurality of separate pictures that are given motion when viewed sequentially. The pictures themselves may be constructed as a spatial pixel array, wherein each pixel may include one or more samples depending on the sampling structure, color space, etc. used. The relationship between pixels and samples may be easily understood by those skilled in the art. The following description focuses on the samples.

[0056] According to an embodiment, the video encoder (503) may encode and compress pictures of a source video sequence into an encoded video sequence (543) in real time or under any other time constraints required by the application. Implementing an appropriate encoding speed is a function of the controller (550). In some embodiments, the controller (550) controls other functional units as described below and is functionally coupled to these units. For the sake of simplicity, couplings are not shown in the figure. The parameters set by the controller (550) may include rate control related parameters (picture skipping, quantizer, lambda value of rate distortion optimization technology, etc.), picture size, group of pictures (GOP) layout, maximum motion vector search range, etc. The controller (550) can be used to have other suitable functions that are related to the video encoder (503) optimized for a certain system design.

[0057] In some embodiments, the video encoder (503) operates in an encoding loop. As a simple description, in embodiments, the encoding loop may include a source encoder (530) (e.g., responsible for creating symbols, such as a symbol stream, based on an input picture to be encoded and a reference picture) and a (local) decoder (533) embedded in the video encoder (503). The decoder (533) reconstructs the symbols to create sample data in a manner similar to that of the (remote) decoder to create sample data (because in the video compression techniques considered in this application, any compression between the symbols and the encoded video bitstream is lossless). The reconstructed sample stream (sample data) is input to a reference picture memory (534). Since the decoding of the symbol stream produces bit-accurate results that are independent of the decoder location (local or remote), the contents of the reference picture memory (534) are also bit-accurately corresponding between the local encoder and the remote encoder. In other words, the reference picture samples "seen" by the prediction part of the encoder are exactly the same as the sample values ​​that the decoder will "see" when using the prediction during decoding. This basic principle of reference picture synchronization (and the drift that occurs when synchronization cannot be maintained, eg due to channel errors) is also used in some related techniques.

[0058] The operation of the "local" decoder (533) may be combined with, for example, Figure 4 The "remote" decoder described in detail for the video decoder (410) is identical. However, additional brief reference is made to Figure 4 , when symbols are available and the entropy encoder (545) and parser (420) are capable of losslessly encoding / decoding the symbols into an encoded video sequence, the entropy decoding portion of the video decoder (410), including the buffer memory (415) and the parser (420), may not be fully implemented in the local decoder (533).

[0059] At this point, it can be observed that any decoder technology other than the parsing / entropy decoding present in the decoder must also be present in the corresponding encoder in substantially the same functional form. For this reason, the present application focuses on decoder operation. The description of encoder technology can be simplified because encoder technology is mutually inverse to the decoder technology described comprehensively. A more detailed description is only needed in certain areas and is provided below.

[0060] During operation, in some embodiments, the source encoder (530) may perform motion compensated predictive coding. The motion compensated predictive coding predictively encodes an input picture with reference to one or more previously encoded pictures from a video sequence designated as "reference pictures." In this manner, the encoding engine (532) encodes the differences between pixel blocks of the input picture and pixel blocks of a reference picture that may be selected as a prediction reference for the input picture.

[0061] The local video decoder (533) may decode the encoded video data of the picture that may be designated as the reference picture based on the symbol created by the source encoder (530). The operation of the encoding engine (532) may be a lossy process. When the encoded video data is available at the video decoder ( Figure 5 When the video sequence is decoded at a remote location (not shown), the reconstructed video sequence may typically be a copy of the source video sequence with some errors. The local video decoder (533) replicates the decoding process that may be performed by the video decoder on the reference picture and may cause the reconstructed reference picture to be stored in the reference picture cache (534). In this way, the video encoder (503) may locally store a copy of the reconstructed reference picture that has common content (absent transmission errors) with the reconstructed reference picture to be obtained by the remote video decoder.

[0062] The predictor (535) may perform a prediction search for the encoding engine (532). That is, for a new picture to be encoded, the predictor (535) may search the reference picture memory (534) for sample data (as candidate reference pixel blocks) or certain metadata, such as reference picture motion vectors, block shapes, etc., that may serve as appropriate prediction references for the new picture. The predictor (535) may operate pixel-by-pixel based on sample blocks to find a suitable prediction reference. In some cases, based on the search results obtained by the predictor (535), it may be determined that the input picture may have prediction references taken from a plurality of reference pictures stored in the reference picture memory (534).

[0063] The controller (550) may manage encoding operations of the source encoder (530), including, for example, setting parameters and subgroup parameters for encoding video data.

[0064] The outputs of all the above functional units may be entropy encoded in an entropy encoder (545). The entropy encoder (545) performs lossless compression on the symbols generated by the various functional units according to techniques such as Huffman coding, variable length coding, arithmetic coding, etc., thereby converting the symbols into a coded video sequence.

[0065] The transmitter (540) may buffer the encoded video sequence created by the entropy encoder (545) in preparation for transmission over a communication channel (560), which may be a hardware / software link to a storage device where the encoded video data may be stored. The transmitter (540) may combine the encoded video data from the video encoder (503) with other data to be transmitted, such as encoded audio data and / or ancillary data streams (source not shown).

[0066] The controller (550) may manage the operation of the video encoder (503). During encoding, the controller (550) may assign a certain coded picture type to each coded picture, but this may affect the coding techniques that can be applied to the corresponding picture. For example, a picture may generally be assigned to any of the following picture types:

[0067] An intra picture (I picture) may be a picture that can be encoded and decoded without using any other picture in the sequence as a prediction source. Some video codecs allow different types of intra pictures, including, for example, Independent Decoder Refresh ("IDR") pictures. Those skilled in the art are aware of the variations of I pictures and their corresponding applications and features.

[0068] A predictive picture (P picture) may be a picture that can be encoded and decoded using intra prediction or inter prediction, which uses at most one motion vector and a reference index to predict sample values ​​for each block.

[0069] Bidirectional predictive pictures (B pictures), which can be pictures that can be encoded and decoded using intra prediction or inter prediction, which uses up to two motion vectors and reference indices to predict the sample values ​​of each block. Similarly, multiple predictive pictures can use more than two reference pictures and associated metadata for reconstruction of a single block.

[0070] The source picture may typically be spatially subdivided into blocks of samples (e.g., blocks of 4×4, 8×8, 4×8, or 16×16 samples), and coded block by block. These blocks may be predictively coded with reference to other (already coded) blocks, which are determined according to the coding allocation applied to the block's corresponding picture. For example, blocks of an I picture may be non-predictively coded, or the blocks may be predictively coded (spatial prediction or intra prediction) with reference to already coded blocks of the same picture. Blocks of pixels of a P picture may be predictively coded by spatial prediction with reference to one previously coded reference picture or by temporal prediction. Blocks of a B picture may be predictively coded by spatial prediction with reference to one or two previously coded reference pictures or by temporal prediction.

[0071] The video encoder (503) may perform encoding operations according to a predetermined video encoding technique or standard, such as ITU-T H.265 Recommendation. In operation, the video encoder (503) may perform various compression operations, including predictive encoding operations that exploit temporal and spatial redundancy in an input video sequence. Thus, the encoded video data may conform to the syntax specified by the video encoding technique or standard used.

[0072] In an embodiment, the transmitter (540) may transmit additional data when transmitting the encoded video. The source encoder (530) may include such data as part of the encoded video sequence. The additional data may include other forms of redundant data such as temporal / spatial / SNR enhancement layers, redundant pictures and slices, SEI messages, VUI parameter set fragments, etc.

[0073] The captured video may be taken as a plurality of source pictures (video pictures) in a temporal sequence. Intra-picture prediction (often simplified to intra-prediction) exploits spatial correlations in a given picture, while inter-picture prediction exploits (temporal or other) correlations between pictures. In an embodiment, a particular picture being encoded / decoded is partitioned into blocks, and the particular picture being encoded / decoded is referred to as the current picture. When a block in the current picture is similar to a reference block in a reference picture that was previously encoded in the video and is still buffered, the block in the current picture may be encoded by a vector called a motion vector. The motion vector points to a reference block in a reference picture, and in the case where multiple reference pictures are used, the motion vector may have a third dimension that identifies the reference picture.

[0074] In some embodiments, bidirectional prediction techniques may be used in inter-picture prediction. According to the bidirectional prediction technique, two reference pictures are used, for example, a first reference picture and a second reference picture that are both before the current picture in the video in decoding order (but may be in the past and future in display order, respectively). A block in the current picture may be encoded by a first motion vector pointing to a first reference block in the first reference picture and a second motion vector pointing to a second reference block in the second reference picture. Specifically, the block may be predicted by a combination of the first reference block and the second reference block.

[0075] In addition, merge mode technology can be used in inter-picture prediction to improve coding efficiency.

[0076] According to some embodiments disclosed in the present application, predictions such as inter-picture prediction and intra-picture prediction are performed in blocks. For example, according to the HEVC standard, pictures in a video picture sequence are divided into coding tree units (CTUs) for compression, and the CTUs in the pictures have the same size, such as 64×64 pixels, 32×32 pixels, or 16×16 pixels. In general, a CTU includes three coding tree blocks (CTBs), which are a luminance CTB and two chrominance CTBs. Furthermore, each CTU can be split into one or more coding units (CUs) using a quadtree. For example, a 64×64 pixel CTU can be split into a 64×64 pixel CU, or 4 32×32 pixel CUs, or 16 16×16 pixel CUs. In an embodiment, each CU is analyzed to determine the prediction type for the CU, such as an inter-prediction type or an intra-prediction type. In addition, depending on temporal and / or spatial predictability, the CU is split into one or more prediction units (PUs). Typically, each PU includes a luminance prediction block (PB) and two chrominance PBs. In an embodiment, the prediction operation in encoding (encoding / decoding) is performed in units of prediction blocks. Taking the luminance prediction block as an example of a prediction block, the prediction block includes a matrix of pixel values ​​(e.g., luminance values), such as 8×8 pixels, 16×16 pixels, 8×16 pixels, 16×8 pixels, and the like.

[0077] Figure 6 1 is a diagram of a video encoder (603) according to another embodiment disclosed in the present application. The video encoder (603) is used to receive a processed block (e.g., a prediction block) of sample values ​​in a current video picture in a video picture sequence, and encode the processed block into an encoded picture that is part of an encoded video sequence. In this embodiment, the video encoder (603) is used to replace Figure 3A video encoder (303) in an embodiment.

[0078] In an HEVC embodiment, a video encoder (603) receives a matrix of sample values ​​for a processing block, such as a prediction block of 8×8 samples. The video encoder (603) uses, for example, rate-distortion (RD) optimization to determine whether to use intra mode, inter mode, or bidirectional prediction mode to encode the processing block. When encoding the processing block in intra mode, the video encoder (603) may use intra prediction techniques to encode the processing block into an encoded picture; and when encoding the processing block in inter mode or bidirectional prediction mode, the video encoder (603) may use inter prediction or bidirectional prediction techniques to encode the processing block into an encoded picture, respectively. In some video encoding techniques, the merge mode may be an inter-picture prediction submode, in which a motion vector is derived from one or more motion vector predictors without the aid of an encoded motion vector component external to the predictor. In some other video encoding techniques, there may be a motion vector component applicable to the subject block. In an embodiment, the video encoder (603) includes other components, such as a mode decision module (not shown) for determining the processing block mode.

[0079] exist Figure 6 In an embodiment of the present invention, the video encoder (603) includes: Figure 6 Shown are an inter-frame encoder (630), an intra-frame encoder (622), a residual calculator (623), a switch (626), a residual encoder (624), a common controller (621), and an entropy encoder (625) coupled together.

[0080] The inter-frame encoder (630) is used to receive samples of a current block (e.g., a processing block), compare the block with one or more reference blocks in a reference picture (e.g., blocks in a previous picture and a subsequent picture), generate inter-frame prediction information (e.g., redundant information description according to an inter-frame coding technique, motion vectors, merge mode information), and calculate an inter-frame prediction result (e.g., a predicted block) based on the inter-frame prediction information using any suitable technique. In some embodiments, the reference picture is a decoded reference picture decoded based on the encoded video information.

[0081] The intra-frame encoder (622) is used to receive samples of a current block (e.g., a processing block), compare the block with an encoded block in the same picture in some cases, generate quantization coefficients after transformation, and in some cases also generate intra-frame prediction information (e.g., intra-frame prediction direction information according to one or more intra-frame coding techniques). In an embodiment, the intra-frame encoder (622) also calculates an intra-frame prediction result (e.g., a predicted block) based on the intra-frame prediction information and a reference block in the same picture.

[0082] The general controller (621) is used to determine general control data and control other components of the video encoder (603) based on the general control data. In an embodiment, the general controller (621) determines the mode of the block and provides a control signal to the switch (626) based on the mode. For example, when the mode is intra mode, the general controller (621) controls the switch (626) to select the intra mode result for use by the residual calculator (623) and controls the entropy encoder (625) to select intra prediction information and add the intra prediction information to the bitstream; and when the mode is inter mode, the general controller (621) controls the switch (626) to select the inter prediction result for use by the residual calculator (623) and controls the entropy encoder (625) to select the inter prediction information and add the inter prediction information to the bitstream.

[0083] The residual calculator (623) is used to calculate the difference (residual data) between the received block and the prediction result selected from the intra-frame encoder (622) or the inter-frame encoder (630). The residual encoder (624) is used to operate based on the residual data to encode the residual data to generate a transform coefficient. In an embodiment, the residual encoder (624) is used to convert the residual data from the spatial domain to the frequency domain and generate a transform coefficient. The transform coefficient is then processed by quantization to obtain a quantized transform coefficient. In various embodiments, the video encoder (603) also includes a residual decoder (628). The residual decoder (628) is used to perform an inverse transform and generate decoded residual data. The decoded residual data can be used appropriately by the intra-frame encoder (622) and the inter-frame encoder (630). For example, the inter-frame encoder (630) can generate a decoded block based on the decoded residual data and the inter-frame prediction information, and the intra-frame encoder (622) can generate a decoded block based on the decoded residual data and the intra-frame prediction information. The decoded blocks are appropriately processed to generate a decoded picture, and in some embodiments, the decoded picture may be buffered in a memory circuit (not shown) and used as a reference picture.

[0084] The entropy encoder (625) is used to format the bitstream to produce an encoded block. The entropy encoder (625) generates various information according to a suitable standard such as the HEVC standard. In an embodiment, the entropy encoder (625) is used to obtain general control data, selected prediction information (such as intra-frame prediction information or inter-frame prediction information), residual information, and other suitable information in the bitstream. It should be noted that according to the disclosed subject matter, when the block is encoded in the inter-frame mode or the merge sub-mode of the bidirectional prediction mode, there is no residual information.

[0085] Figure 7FIG. 7 is a diagram of a video decoder (710) according to another embodiment disclosed in the present application. The video decoder (710) is used to receive an encoded image as part of an encoded video sequence and decode the encoded image to generate a reconstructed picture. In an embodiment, the video decoder (710) is used to replace Figure 3 A video decoder (310) of an embodiment.

[0086] exist Figure 7 In one embodiment, the video decoder (710) includes: Figure 7 An entropy decoder (771), an inter-frame decoder (780), a residual decoder (773), a reconstruction module (774) and an intra-frame decoder (772) coupled together are shown in FIG.

[0087] The entropy decoder (771) may be used to reconstruct certain symbols from the encoded picture, which represent syntax elements constituting the encoded picture. Such symbols may include, for example, a mode for encoding the block (e.g., intra mode, inter mode, bidirectional prediction mode, a merged sub-mode of the latter two, or another sub-mode), prediction information (e.g., intra prediction information or inter prediction information) that may identify certain samples or metadata for prediction by the intra decoder (772) or the inter decoder (780), respectively, residual information in the form of, for example, quantized transform coefficients, and the like. In an embodiment, when the prediction mode is inter or bidirectional prediction mode, the inter prediction information is provided to the inter decoder (780); and when the prediction type is an intra prediction type, the intra prediction information is provided to the intra decoder (772). The residual information may be inverse quantized and provided to the residual decoder (773).

[0088] The inter-frame decoder (780) is used for receiving the inter-frame prediction information and generating an inter-frame prediction result based on the inter-frame prediction information.

[0089] The intra-frame decoder (772) is used to receive intra-frame prediction information and generate a prediction result based on the intra-frame prediction information.

[0090] The residual decoder (773) is used to perform inverse quantization to extract dequantized transform coefficients, and process the dequantized transform coefficients to convert the residual from the frequency domain to the spatial domain. The residual decoder (773) may also require some control information (to obtain the quantizer parameter QP), and this information can be provided by the entropy decoder (771) (the data path is not indicated because this is only low-volume control information).

[0091] The reconstruction module (774) is used to combine the residual output by the residual decoder (773) with the prediction result (which can be output by the inter-frame prediction module or the intra-frame prediction module) in the spatial domain to form a reconstructed block, which can be part of a reconstructed picture, which in turn can be part of a reconstructed video. It should be noted that other suitable operations such as deblocking operations can be performed to improve visual quality.

[0092] It should be noted that the video encoder (303), video encoder (503) and video encoder (603) and video decoder (310), video decoder (410) and video decoder (710) may be implemented using any suitable technology. In an embodiment, the video encoder (303), video encoder (503) and video encoder (603) and video decoder (310), video decoder (410) and video decoder (710) may be implemented using one or more integrated circuits. In another embodiment, the video encoder (303), video encoder (503) and video encoder (603) and video decoder (310), video decoder (410) and video decoder (710) may be implemented using one or more processors that execute software instructions.

[0093] Block-based compensation from different pictures may be referred to as motion compensation. Block compensation may also be performed from previously reconstructed areas within the same picture, which may be referred to as intra-image block compensation, intra-block copy (IBC) or current picture referencing (CPR). For example, a displacement vector indicating the offset between a current block and a reference block is referred to as a block vector. According to some embodiments, a block vector points to a reference block that has been reconstructed and can be used for reference. In addition, for parallel processing considerations, reference areas beyond tile / slice boundaries or wavefront trapezoid boundaries may also be excluded from reference to block vectors. Due to these constraints, block vectors may be different from motion vectors in motion compensation, where motion vectors may be any value (positive or negative, in the x or y direction).

[0094] The encoding and decoding of block vectors can be explicit or implicit. In the explicit mode, sometimes referred to as Advanced Motion Vector Prediction (AMVP) mode in inter-frame coding, the difference between the block vector and its predicted value is signaled. In the implicit mode, the block vector is recovered from the predicted value of the block vector using a similar manner as the motion vector in merge mode. In some embodiments, the resolution of the block vector is limited to integer positions. In other embodiments, the resolution of the block vector may be allowed to point to fractional positions.

[0095] A block-level flag (called an IBC flag) can be used to signal the use of intra-block copying at the block level. In one embodiment, if the current block is not encoded in merge mode, the IBC flag is signaled. The IBC flag can also be signaled by a reference index method that is performed by treating the current decoded picture as a reference picture. In HEVC Screen Content Coding (SCC), such reference pictures are placed at the last position of the list. This special reference picture can also be managed with other temporal reference pictures in the DPB. IBC can also include some changes, such as flipping IBC changes (for example, flipping the reference block horizontally or vertically before using it to predict the current block), or changes based on rows (IBC) (for example, each compensation unit in an MxN coding block is an Mx1 row or a 1xN row).

[0096] Figure 8 An embodiment of intra-frame image block compensation (eg, intra-frame block copy mode) is shown. Figure 8 , the current picture 800 includes a group of block regions that have been encoded / decoded (i.e., gray squares) and a group of block regions that have not yet been encoded / decoded (i.e., white squares). A block 802 of one of the block regions that have not yet been encoded / decoded may be associated with a block vector 804, wherein the block vector 804 points to another block 806 that has been previously encoded / decoded. Therefore, any motion information associated with the block 806 may be used to encode / decode the block 802.

[0097] In some embodiments, the search range of the CPR mode is limited to the current CTU. The effective memory requirement for storing reference samples for the CPR mode is 1 CTU size of samples. Considering the existing reference sample memory for storing reconstructed samples in the current 64x64 area, 3 64x64 sized reference sample memories are also required. Embodiments of the present disclosure extend the effective search range of the CPR mode to certain parts of the left CTU, while the total memory requirement for storing reference pixels remains unchanged (1 CTU size, a total of 4 64x64 reference sample memories).

[0098] exist Fig.9A In the example, the upper left region of CTU 900 is the current region being decoded. When decoding the upper left region of CTU 900, entry [1] of the reference sample memory is overwritten by samples from that region, such as Fig. 10A As shown (e.g., one or more memory locations that are covered have diagonal cross-hatching). Fig. 9B In the example, the upper right region of CTU 900 is the next current region being decoded. When decoding the upper right region of CTU 900, entry [2] of the reference sample memory is overwritten by samples from that region, such as Fig. 10B As shown. Fig. 9C In the example, the lower left region of CTU 900 is the next current region being decoded. When decoding the lower left region of CTU 900, the entry [3] of the reference sample memory is overwritten by the sample from that region, such as Fig. 10C As shown. Fig.9D In the example, the lower right region of CTU 900 is the next current region being decoded. When decoding the lower right region of CTU 900, the entry [3] of the reference sample memory is overwritten by the sample from this region, as shown in FIG. Fig. 10D shown.

[0099] In some embodiments, the bitstream consistency condition is that the valid block vector (mvL, at 1 / 16 pixel resolution) should follow the conditions specified below. In some embodiments, the luma motion vector mvL is subject to the following constraints A1, A2, B1, C1 and C2.

[0100] In the first constraint (A1), when the derivation process of block availability (e.g., the neighboring block availability check process) is called with the current luminance position (xCurr, yCurr) set equal to (xCb, yCb) and the neighboring luminance position (xCb+(mvL[0]>>4)+cbWidth-1, yCb+(mvL[1]>>4)+cbHeight-1) as input, the output should be equal to true.

[0101] In the second constraint (A2), when the derivation process of block availability (e.g., the neighboring block availability check process) is called with the current luminance position (xCurr, yCurr) set equal to (xCb, yCb) and the neighboring luminance position (xCb+(mvL[0]>>4)+cbWidth-1, yCb+(mvL[1]>>4)+cbHeight-1) as input, the output should be equal to true.

[0102] In the third constraint (B1), one or both of the following conditions are true:

[0103] (i) The value of (mvL[0]>>4) + cbWidth is less than or equal to 0.

[0104] (ii) The value of (mvL[1]>>4) + cbHeight is less than or equal to 0.

[0105] In the fourth constraint C1, the following conditions are true:

[0106] (i)(yCb+(mvL[1]>>4))>>CtbLog2SizeY=

[0107] yCb>>CtbLog2SizeY

[0108] (ii)(yCb+(mvL[1]>>4)+cbHeight-1)>>CtbLog2SizeY=

[0109] yCb>>CtbLog2SizeY

[0110] (iii)(xCb+(mvL[0]>>4))>>CtbLog2SizeY>=

[0111] (xCb>>CtbLog2SizeY)-1

[0112] (iv)(xCb+(mvL[0]>>4)+cbWidth-1)>>CtbLog2SizeY<=

[0113] (xCb>>CtbLog2SizeY)

[0114] In the fifth constraint C2, when (xCb+(mvL[0]>>4))>>CtbLog2SizeY is equal to (xCb>>CtbLog2SizeY)–1, when the block availability derivation process (e.g., the neighboring block availability check process) is called using the current luminance position (xCurr, yCurr) set equal to (xCb, yCb) and the neighboring luminance positions (((xCb+(mvL[0]>>4)+CtbSizeY)>>(CtbLog2SizeY-1))<<(CtbLog2SizeY-1), ((yCb+(mvL[1]>>4))>>(CtbLog2SizeY-1))<<(CtbLog2SizeY-1)) as input, the output should be equal to false.

[0115] In the above equation, xCb and yCb are the x and y coordinates of the current block, respectively. The variables cbHeight and cbWidth are the height and width of the current block, respectively. The variable CtbLog2sizeY refers to the CTU size in the log2 domain. For example, CtbLog2sizeY=7 indicates that the CTU size is 128x 128. The variables mvL0[0] and mvL0[1] refer to the x and y components of the block vector mvL0, respectively. If the output is false, it is determined that the samples of the reference block are available (for example, the adjacent block can be used for intra-block copying). If the output is true, it is determined that the samples of the reference block are not available.

[0116] According to some embodiments, the history-based MVP (HMVP) method includes HMVP candidates defined as motion information of previously coded blocks. During the encoding / decoding process, a table containing multiple HMVP candidates is maintained. When a new slice is encountered, the table is cleared. When there is an inter-coded non-affine block, the related motion information is added as the last entry of the table as a new HMVP candidate. The encoding process of the HMVP method is as follows: Fig.11A Described in.

[0117] The size S of the table is set to 6, which means that at most 6 HMVP candidates can be added to the table. When inserting a new motion candidate into the table, a constrained FIFO rule is used so that a redundancy check is first applied to determine if the same HMVP exists in the table. If the same HMVP is found, the same HMVP is deleted from the table and all HMVP candidates are moved forward (i.e., the index is reduced by 1). Fig. 11B An example of inserting a new motion candidate into the HMVP table is shown.

[0118] HMVP candidates can be used in the merge candidate list construction process. The latest HMVP candidates in the table are checked in turn and inserted into the candidate list after the TMVP candidate. Pruning can be applied to spatial or temporal merge candidates of HMVP candidates, excluding sub-block motion candidates (ie, ATMVP).

[0119] In some embodiments, to reduce the number of pruning operations, the number of HMVP candidates to be checked (denoted by L) is set to L = (N <= 4)? M: (8-N), where N represents the number of available non-subblock merge candidates and M represents the number of HMVP candidates available in the table. In addition, once the total number of available merge candidates reaches the maximum allowed number of merge candidates signaled minus one, the process of constructing a merge candidate list from the HMVP list is terminated. In addition, the number of pairs used to combine bidirectional prediction merge candidate derivations is reduced from 12 to 6.

[0120] HMVP candidates can also be used in the AMVP candidate list construction process. The motion vectors of the last K HMVP candidates in the table are inserted after the TMVP candidates. Only HMVP candidates with the same reference picture as the AMVP target reference picture are used to build the AMVP candidate list. Pruning is applied to HMVP candidates. In some applications, K is set to 4, while the AMVP list size remains unchanged (i.e., equal to 2).

[0121] According to some embodiments, when intra block copy is operated as a mode separate from inter mode, a separate history buffer called HBVP may be used to store previously encoded intra block copy block vectors. As a mode separate from inter prediction, a simplified block vector derivation process is desired for intra block copy mode. The candidate list for IBC BV prediction in AMVP mode can share the candidate list used in IBC merge mode with 2 spatial candidates + 5 HBVP candidates (merge candidate list).

[0122] The merge candidate list size for IBC mode may be specified as MaxNumMergeCand. MaxNumMergeCand may be determined by the inter mode merge candidate list size MaxNumMergeCand, which in some examples is specified as six_minus_max_num_merge_cand. The variable six_minus_max_num_merge_cand may specify the maximum number of merge motion vector prediction (MVP) candidates supported in a slice subtracted from 6.

[0123] In some examples, the maximum number of merge MVP candidates MaxNumMergeCand can be derived as:

[0124] Equation (1): MaxNumMergeCand=6-six_minus_max_num_merge_cand

[0125] The value of MaxNumMergeCand can be in the range of 1 to 6 (including the end value). In some video codec systems, for all I / P / B slices, the merge list size of the IBC mode and the merge list size of the inter-frame merge mode are signaled separately. The range of this size can be the same as the inter-frame merge mode (for example, from 1 to 6, including the end value). In some examples, the maximum number of IBC candidates MaxNumIbcMergeCand can be derived as:

[0126] Equation (2): MaxNumIBCMergeCand=6-six_minus_max_num_ibc_merge_cand

[0127] In equation (2), the variable six_minus_max_num_ibc_merge_cand specifies the maximum number of IBC merge motion vector prediction MVP candidates supported in the slice subtracted from 6. The value of MaxNumIBCMergeCand can be in the range of 1 to 6 (including the end value). In some video coding systems, the merge index signaling for the IBC merge mode can still share the merge index signaling for the inter-frame merge mode. At this point, the IBC merge mode and the inter-frame merge mode can share the same syntax elements for the merge index. Because the merge index is binarized using a truncated Rice (TR) code, the maximum length of the merge index is MaxNumMergeCand–1. However, when MaxNumIbcMergeCand is not equal to MaxNumMergeCand, a solution for merge index signaling is needed.

[0128] The embodiments of the present disclosure may be used alone or in combination in any order. In addition, each method, encoder and decoder according to the embodiments of the present disclosure may be implemented by a processing circuit (e.g., one or more processors, or one or more integrated circuits). In one example, one or more processors execute a program stored in a non-volatile computer-readable medium. According to some embodiments, the term block may be interpreted as a prediction block, a coding block, or a coding unit (i.e., CodingUnit, CU).

[0129] According to some embodiments, the number of maximum merge sizes of merge index binarization is set to be switchable between the number of MaxNumMergeCand and MaxNumIbcMergeCand. For example, when the current block is encoded in IBC mode, the maximum merge size of the merge index is MaxNumIbcMergeCand. However, when the current block is not encoded in IBC mode, the maximum merge size of the merge index is MaxNumMergeCand. Table 1 illustrates example syntax elements and associated binarization.

[0130]

[0131] Table 1

[0132] As shown in Table 1, the binarization of the merge index (i.e., merge_idx[][]) is based on whether the current block is encoded in IBC mode. In addition, FL refers to the fixed length. cMax refers to the maximum possible value of the variable length code. eRiceParam refers to the Rice parameter of the variable length code. The Rice parameter can be used to determine the binary code of each input value. In the truncated binary code, the Rice parameter is 0.

[0133] According to some embodiments, the number of maximum merge sizes for merge index binarization is set to the maximum number between MaxNumMergeCand and MaxNumIbcMergeCand. Since the value of MaxNumMergeCand is not signaled in an I slice / tile group, the inferred value of MaxNumMergeCand may be 1 (i.e., the minimum possible value of MaxNumIbcMergeCand). Therefore, when MaxNumMergeCand is not signaled, since the value of MaxNumMergeCand is inferred to be 1, the value of six_minus_max_num_merge_cand is inferred to be 5. Therefore, in equation (1), since six_minus_max_num_merge_cand is 5, MaxNumMergeCand is equal to 1. In equation (2), the value of MaxNumIbcMergeCand is in the range of 1 to 6 (including the end value).

[0134] Table 2 illustrates example grammars and associated binarizations.

[0135]

[0136] Table 2

[0137] As shown in Table 2, the binarization of the merge index (ie, merge_idx[][]) is based on whether the maximum number of merge mode candidates (ie, MaxNumMergeCand) is greater than the maximum number of IBC candidates (ie, MaxNumIbcMergeCand).

[0138] According to some embodiments, the range of MaxNumIbcMergeCand should be less than or equal to the range of MaxNumMergeCand. Since the value of MaxNumMergeCand is not signaled in I slices / tile groups, the value of MaxNumMergeCand is inferred to be 6. Therefore, in equation (1), since the value of MaxNumMergeCand is inferred to be 6, the value of six_minus_max_num_merge_cand is inferred to be 0. In some embodiments, when the signaled MaxNumIbcMergeCand value is greater than the value of MaxNumMergeCand, MaxNumIbcMergeCand is clipped to MaxNumMergeCand. Therefore, in equation (2), if the slice type is I, the value of MaxNumIbcMergeCand should be in the range of 1 to 6 (including the end values). However, if the slice type is P or B, the value of MaxNumIbcMergeCand is in the range of 1 to MaxNumMergeCand (including the end value). Therefore, when the slice type is P or B (that is, MaxNumMergeCand is not signaled), the value of MaxNumIbcMergeCand can be determined as follows: MaxNumIbcMergeCand=min(MaxNumIbcMergeCand,MaxNumMergeCand).

[0139] Fig.12 An embodiment of a video decoding process performed by a video decoder such as a video decoder (710) is shown. The process may begin at step (S1200) where an encoded video bitstream including a current picture is received. The process proceeds to step (S1202) where a predetermined condition associated with signaling data included in the encoded video bitstream is determined.

[0140] The process proceeds to step (S1204), and based on a predetermined condition, the index size in the signaling data of the candidate list of vector prediction values ​​is set to one of the maximum number of merge mode candidates and the number of IBC candidates. As an example, the index can be a merge index included in the encoded video bitstream. As an example, the predetermined condition includes determining whether the current block is encoded in IBC mode. If the current block is encoded in IBC mode, the index size is set to MaxNumIbcMergeCand. However, if the current block is not encoded in IBC mode, the size of the index is set to MaxNumMergeCand.

[0141] As another example, the predetermined condition includes determining whether the maximum number of merge mode candidates is greater than the maximum number of IBC candidates. If the maximum number of merge mode candidates is greater than the maximum number of IBC candidates, the size of the index is set to MaxNumMergeCand. However, if the maximum number of merge mode candidates is less than the maximum number of IBC candidates, the size of the index is set to MaxNumIbcMergeCand.

[0142] The process proceeds from step (S1204) to step (S1206), where a candidate list is constructed using vector prediction values. For example, if the current block is encoded in merge mode, the candidate list is a merge list and the vector prediction values ​​are motion vectors. In another example, if the current block is encoded in IBC mode, the candidate list is a list of block vector prediction values. The process continues from step (S1208) to retrieve the vector prediction value of the candidate list according to the index, wherein the value of the index does not exceed the determined index size. For example, the value of the index used to retrieve the vector prediction value from the candidate list cannot exceed the size of the index determined in step (S1204). The process proceeds to step (S1210), and the current block is decoded according to the retrieved vector prediction value.

[0143] Fig.13 An embodiment of a video decoding process performed by a video decoder such as a video decoder (710) is shown. The process may begin at step (S1300) where an encoded video bitstream including a current picture is received. The process proceeds to step (S1302) where signaling data from the encoded video bitstream is retrieved for the current block. The process proceeds to step (S1304) where a determination is made as to whether the maximum number of merge candidates is included in the signaling data retrieved for the current block. For example, a determination is made as to whether to signal MaxNumMergeCand. As discussed above, in some examples, MaxNumMergeCand is not signaled for an I slice / tile group type, but is instead signaled for a P or B slice / tile group type.

[0144] The process proceeds to step (S1306), and the maximum number of intra-block copy (IBC) candidates is set based on whether the signaling data of the determined current block includes the maximum number of merge candidates. For example, if MaxNumMergeCand is not signaled, the value of MaxNumIbcMergeCand is in the range of 1 to 6 (including the end value). However, if MaxNumMergeCand is signaled, the value of MaxNumIbcMergeCand is in the range of 1 to MaxNumMergeCand (including the end value).

[0145] In some examples, a coding unit contains samples of luma and chroma components. These samples of chroma components may have an independent or separate partition tree structure compared to the samples of luma components. In some examples, a separate coding tree structure starts at the CTU level. Therefore, a chroma CU (e.g., a CU containing only two chroma components) may be larger than the luma counterpart of the chroma CU at the corresponding sample position.

[0146] According to some embodiments, in a first method, when a dual tree structure is used, a chroma block may be encoded in IBC mode when at least the following conditions are met:

[0147] 1. For each sub-block area in the chroma CU, encode the co-located luma area in IBC mode.

[0148] 2. All co-located luma area samples of a chroma CU have the same block vector.

[0149] 3. The common block vector derived for the entire chroma CU is a valid BV. This means that the BV points to an already reconstructed area in the current picture and is within the given constraint area of ​​the chroma component.

[0150] Based on the first approach, the decoder side is able to treat the chroma CU as a whole CU, rather than as a sub-block based CU. Therefore, it is sufficient to decode the CU using a single BV derived from the co-located luma region (e.g., usually the upper left corner of the CU).

[0151] According to some embodiments, in the second method, when a dual tree structure is used, a chroma IBC mode with a dual tree structure can be enabled using different conditions. In one embodiment, when (i) the corresponding luminance samples of all chroma samples belong to the same luminance coding block; and (ii) the same luminance coding block is encoded in IBC mode, the chroma block can be encoded using IBC mode. As an example, the condition is checked by evaluating two corners of the chroma CU. If the luminance corresponding part of the upper left chroma sample and the luminance corresponding part of the lower right chroma sample belong to the same luminance coding block, the corresponding luminance area of ​​the entire chroma CU belongs to the same luminance coding block. In another embodiment, when corresponding luminance encoding is performed, the chroma block can be encoded using IBC mode.

[0152] Based on the second method, the decoder side is able to treat the chroma CU as a whole CU, rather than as a sub-block based CU. Therefore, it is sufficient to decode the CU using a single BV derived from the co-located luma region (usually the upper left corner of the CU).

[0153] According to some embodiments, for the first method or the second method of the dual tree structure, the non-limiting embodiments disclosed below show how to use the dual tree to signal the use of the chroma IBC mode when the above conditions in the first method or the second method are met.

[0154] In one embodiment, the above constraints of the IBC mode are implemented for chroma CUs with a dual-tree structure so that a flag (i.e., ibc_flag) is signaled for each chroma CU when applicable. However, in this embodiment, the signaled ibc_flag is true only when all conditions of the first method or all conditions of the second method are met. Otherwise, the signaled ibc_flag is false. In some examples, when all conditions of the first method or the second method are met, based on the implementation of the encoder, the signaled ibc_flag is false.

[0155] In another embodiment, the above-mentioned constraint that the chroma CU with a dual tree structure uses the IBC mode is implemented so that the use flag (e.g., ibc_flag) is not signaled. For example, for a chroma CU with a dual tree structure, when all conditions of the first method or all conditions of the second method are met, the CU is encoded using the IBC mode, and ibc_flag is inferred to be true. Otherwise, ibc_flag is not signaled, and ibc_flag is inferred to be false.

[0156] The above techniques may be implemented as computer software via computer-readable instructions and physically stored in one or more computer-readable media. Fig.14 A computer system (1400) is shown that is suitable for implementing certain embodiments of the disclosed subject matter.

[0157] The computer software may be encoded in any suitable machine code or computer language, and may be assembled, compiled, linked, or the like to create a code comprising instructions, which may be directly executed by one or more computer central processing units (CPUs), graphics processing units (GPUs), etc., or executed by decoding, microcode, or the like.

[0158] The instructions may be executed on various types of computers or components thereof, including, for example, personal computers, tablet computers, servers, smartphones, gaming devices, IoT devices, etc.

[0159] Fig.14 The components shown for the computer system (1400) are exemplary in nature and are not intended to limit the scope of use or functionality of the computer software implementing the embodiments of the present application. The configuration of the components should not be interpreted as having any dependency or requirement on any component or combination of components shown in the exemplary embodiment of the computer system (1400).

[0160] The computer system (1400) may include certain human-computer interface input devices. Such human-computer interface input devices may respond to input from one or more human users through tactile input (e.g., keyboard input, sliding, data glove movement), audio input (e.g., sound, applause), visual input (e.g., gestures), and olfactory input (not shown). The human-computer interface devices may also be used to capture certain media that are not necessarily directly related to human conscious input, such as audio (e.g., speech, music, ambient sound), images (e.g., scanned images, photographic images obtained from a still image camera), and videos (e.g., two-dimensional video, three-dimensional video including stereoscopic video).

[0161] The human-computer interface input device may include one or more of the following (only one of which is drawn): keyboard (1401), mouse (1402), touchpad (1403), touch screen (1410), data gloves (not shown), joystick (1405), microphone (1406), scanner (1407), camera (1408).

[0162] The computer system (1400) may also include certain human-computer interface output devices. Such human-computer interface output devices may stimulate one or more human user senses through, for example, tactile output, sound, light, and smell / taste. Such human-computer interface output devices may include tactile output devices (e.g., tactile feedback through a touch screen (1410), a data glove (not shown), or a joystick (1405), but there may also be tactile feedback devices that are not used as input devices), audio output devices (e.g., speakers (1409), headphones (not shown)), visual output devices (e.g., screens (1410) including cathode ray tube screens, liquid crystal screens, plasma screens, organic light emitting diode screens, each of which has or does not have a touch screen input function, each of which has or does not have a tactile feedback function - some of which can output two-dimensional visual output or output of more than three dimensions through means such as stereoscopic picture output; virtual reality glasses (not shown), holographic displays, and smoke boxes (not shown)) and printers (not shown).

[0163] The computer system (1400) may also include human-accessible storage devices and their associated media, such as optical media including high-density read-only / rewritable compact disks (CD / DVD ROM / RW) (1420) with CD / DVD or similar media (1421), thumb drives (1422), removable hard disk drives or solid state drives (1423), traditional magnetic media such as tapes and floppy disks (not shown), special-purpose ROM / ASIC / PLD-based devices such as security software protectors (not shown), and the like.

[0164] Those skilled in the art should also understand that the term "computer-readable media" used in connection with the disclosed subject matter does not include transmission media, carrier waves, or other transient signals.

[0165] The computer system (1400) may also include an interface to one or more communication networks. For example, the network may be wireless, wired, or optical. The network may also be a local area network, a wide area network, a metropolitan area network, an in-vehicle network, an industrial network, a real-time network, a delay-tolerant network, and the like. The network also includes local area networks such as Ethernet, wireless local area networks, cellular networks (GSM, 3G, 4G, 5G, LTE, etc.), television wired or wireless wide area digital networks (including cable television, satellite television, and terrestrial broadcast television), in-vehicle and industrial networks (including CANBus), and the like. Some networks typically require an external network interface adapter for connecting to some universal data ports or peripheral buses (1449) (e.g., a USB port of the computer system (1400)); other systems are typically integrated into the core of the computer system (1400) by connecting to a system bus as described below (e.g., an Ethernet interface integrated into a PC computer system or a cellular network interface integrated into a smart phone computer system). By using any of these networks, the computer system (1400) can communicate with other entities. The communication can be one-way, for receiving only (e.g., wireless television), one-way for sending only (e.g., CAN bus to certain CAN bus devices), or two-way, such as to other computer systems via a local or wide area digital network. Each of the above networks and network interfaces can use certain protocols and protocol stacks.

[0166] The above-mentioned human-machine interface devices, human-accessible storage devices, and network interfaces may be connected to the core (1440) of the computer system (1400).

[0167] The core (1440) may include one or more central processing units (CPUs) (1441), graphics processing units (GPUs) (1442), dedicated programmable processing units in the form of field programmable gate arrays (FPGAs) (1443), hardware accelerators for specific tasks (1444), etc. These devices, as well as read-only memory (ROM) (1445), random access memory (1446), internal mass storage (e.g., internal non-user accessible hard disk drives, solid-state drives, etc.) (1447), etc., may be connected via a system bus (1448). In some computer systems, the system bus (1448) may be accessed in the form of one or more physical plugs so that it can be expanded by additional central processing units, graphics processing units, etc. Peripheral devices may be directly attached to the core's system bus (1448), or connected via a peripheral bus (1449). The architecture of the peripheral bus includes PCI, USB, etc.

[0168] The CPU (1441), GPU (1442), FPGA (1443) and accelerator (1444) can execute certain instructions, which can be combined to form the above-mentioned computer code. The computer code can be stored in ROM (1445) or RAM (1446). Transition data can also be stored in RAM (1446), while permanent data can be stored in, for example, internal mass storage (1447). Fast storage and retrieval of any memory device can be achieved by using a cache memory, which can be closely associated with one or more CPUs (1441), GPUs (1442), mass storage (1447), ROM (1445), RAM (1446), etc.

[0169] The computer readable medium may have computer code thereon for performing various computer-implemented operations. The medium and computer code may be specially designed and constructed for the purpose of this application, or may be medium and code well known and available to those skilled in the art of computer software.

[0170] As an example and not a limitation, a computer system having an architecture (1400), in particular a core (1440), can provide the function of executing software contained in one or more tangible computer-readable media as a processor (including a CPU, a GPU, an FPGA, an accelerator, etc.). Such a computer-readable medium can be a medium associated with the above-mentioned user-accessible mass storage, as well as a specific memory of the core (1440) having non-volatility, such as a core internal mass storage (1447) or a ROM (1445). Software implementing various embodiments of the present application can be stored in such a device and executed by the core (1440). Depending on specific needs, the computer-readable medium may include one or more storage devices or chips. The software can enable the core (1440), in particular the processor therein (including a CPU, a GPU, an FPGA, etc.) to perform a specific process or a specific part of a specific process described herein, including defining a data structure stored in the RAM (1446) and modifying such a data structure according to a software-defined process. Additionally or alternatively, the computer system may provide functionality hardwired in logic or otherwise contained in circuitry (e.g., accelerator (1444)) that may operate in place of or in conjunction with software to perform a particular process or a particular portion of a particular process described herein. Where appropriate, references to software may include logic and vice versa. Where appropriate, references to computer-readable media may include circuitry (e.g., an integrated circuit (IC)) storing the executing software, circuitry containing the executing logic, or both. The present application includes any suitable combination of hardware and software.

[0171] Appendix A: Acronyms

[0172] JEM: Joint Development Model

[0173] VVC: Versatile Video Coding

[0174] BMS: Benchmark Collection

[0175] MV: Motion Vector

[0176] HEVC: High Efficiency Video Coding

[0177] SEI: Supplemental Enhancement Information

[0178] VUI: Video Availability Information

[0179] GOP: Group of Pictures

[0180] TU: Transform Unit

[0181] PU: prediction unit

[0182] CTU: Coding Tree Unit

[0183] CTB: Coding Tree Block

[0184] PB: prediction block

[0185] HRD: Hypothesized Reference Decoder

[0186] SNR: Signal to Noise Ratio

[0187] CPU: Central Processing Unit

[0188] GPU: Graphics Processing Unit

[0189] CRT: cathode ray tube

[0190] LCD: Liquid Crystal Display

[0191] OLED: Organic Light Emitting Diode

[0192] CD: compact disc

[0193] DVD: Digital Video Disc

[0194] ROM: Read Only Memory

[0195] RAM: Random Access Memory

[0196] ASIC: Application-Specific Integrated Circuit

[0197] PLD: Programmable Logic Device

[0198] LAN: Local Area Network

[0199] GSM: Global System for Mobile Communications

[0200] LTE: Long Term Evolution

[0201] CANBus: Controller Area Network Bus

[0202] USB: Universal Serial Bus

[0203] PCI: Peripheral Component Interconnect

[0204] FPGA: Field Programmable Gate Array

[0205] SSD: Solid State Drive

[0206] IC: Integrated Circuit

[0207] CU: Coding Unit

[0208] Although the present application has described a number of exemplary embodiments, various changes, arrangements and various equivalent substitutions of the embodiments are within the scope of the present application. Therefore, it should be understood that those skilled in the art can design a variety of systems and methods, which, although not explicitly shown or described herein, embody the principles of the present application and are therefore within the spirit and scope of the present application.

[0209] (1) A video decoding method, comprising: receiving an encoded video bitstream including a current picture; determining a predetermined condition associated with signaling data included in the encoded video bitstream; determining, according to the predetermined condition, a size of an index of a candidate list for a vector prediction value included in the signaling data based on the number of merge mode candidates and the number of intra block copy (IBC) candidates; constructing the candidate list using the vector prediction value; retrieving the vector prediction value in the candidate list according to the index, wherein the value of the index does not exceed the size of the determined index; and decoding the current block according to the retrieved vector prediction value.

[0210] (2) The video decoding method according to feature (1), wherein the predetermined condition includes determining whether the current block is encoded in IBC mode.

[0211] (3) A video decoding method according to feature (2), wherein, if it is determined that the current block is encoded in the IBC mode, the size of the index is set to the maximum number of IBC candidates; if it is determined that the current block is not encoded in the IBC mode, the size of the index is set to the maximum number of merge mode candidates.

[0212] (4) The video decoding method according to any one of features (1) to (3), wherein the predetermined condition includes determining whether the maximum number of merge mode candidates is greater than the maximum number of IBC candidates.

[0213] (5) A video decoding method according to feature (4), wherein if it is determined that the maximum number of merge mode candidates is greater than the maximum number of IBC candidates, the size of the index is set to the maximum number of merge mode candidates; if it is determined that the maximum number of merge mode candidates is less than the maximum number of IBC candidates, the size of the index is set to the maximum number of IBC candidates.

[0214] (6) A video decoding method, comprising: receiving an encoded video bitstream including a current picture; retrieving signaling data of the encoded video bitstream for a current block; determining whether the signaling data retrieved for the current block includes a maximum number of merge candidates; and, based on the determination of whether the signaling data of the current block includes the maximum number of merge candidates, setting a maximum number of intra-block copy (IBC) candidates.

[0215] (7) According to the video decoding method described in feature (6), if it is determined that the maximum number of merge candidates is not included in the signaling data, the maximum number of IBC candidates is set to a value between 1 and 6.

[0216] (8) According to the video decoding method described in feature (7), if it is determined that the signaling data includes the maximum number of merge candidates, the maximum number of IBC candidates is set to a value between 1 and the maximum number of merge candidates.

[0217] (9) A video decoding device for video decoding, comprising a processing circuit, for: receiving an encoded video bit stream including a current picture; determining a predetermined condition associated with signaling data included in the encoded video bit stream; determining, according to the predetermined condition, a size of an index of a candidate list for vector prediction values ​​included in the signaling data based on the number of merge mode candidates and the number of intra-block copy (IBC) candidates; constructing the candidate list using the vector prediction values; retrieving the vector prediction values ​​in the candidate list according to the index, wherein the value of the index does not exceed the size of the determined index; and decoding the current block according to the retrieved vector prediction values.

[0218] (10) The video decoding device according to feature (9), wherein the predetermined condition includes the processing circuit determining whether the current block is encoded in IBC mode.

[0219] (11) A video decoding device according to feature (10), wherein if it is determined that the current block is encoded in the IBC mode, the processing circuit is used to set the size of the index to the maximum number of IBC candidates; if it is determined that the current block is not encoded in the IBC mode, the processing circuit is used to set the size of the index to the maximum number of merge mode candidates.

[0220] (12) The video decoding device according to any one of features (9) to (11), wherein the predetermined condition includes determining whether the maximum number of merge mode candidates is greater than the maximum number of IBC candidates.

[0221] (13) A video decoding device according to feature (12), wherein if it is determined that the maximum number of merge mode candidates is greater than the maximum number of IBC candidates, the processing circuit is used to set the size of the index to the maximum number of merge mode candidates; if it is determined that the maximum number of merge mode candidates is less than the maximum number of IBC candidates, the processing circuit is used to set the size of the index to the maximum number of IBC candidates.

[0222] (14) A video decoder device for video decoding, comprising a processing circuit, configured to: receive an encoded video bitstream including a current picture; retrieve signaling data of the encoded video bitstream for a current block; determine whether the signaling data retrieved for the current block includes a maximum number of merge candidates; and, based on the determination of whether the signaling data of the current block includes the maximum number of merge candidates, set a maximum number of intra-block copy (IBC) candidates.

[0223] (15) A video decoder according to feature (14), wherein if it is determined that the maximum number of merge candidates is not included in the signaling data, the maximum number of IBC candidates is set to a value between 1 and 6.

[0224] (16) A video decoder according to feature (15), wherein if it is determined that the signaling data includes the maximum number of merge candidates, the maximum number of IBC candidates is set to a value between 1 and the maximum number of merge candidates.

[0225] (17) A non-volatile computer-readable medium storing instructions which, when executed by a processor in a video decoder, cause the processor to execute a method comprising: receiving an encoded video bitstream including a current picture; determining a predetermined condition associated with signaling data included in the encoded video bitstream; determining, based on the predetermined condition and the number of merge mode candidates and the number of intra-block copy (IBC) candidates, a size of an index of a candidate list for vector prediction values ​​included in the signaling data; constructing the candidate list using the vector prediction values; retrieving a vector prediction value from the candidate list based on the index, wherein the value of the index does not exceed the size of the determined index; and decoding the current block based on the retrieved vector prediction value.

[0226] (18) The non-transitory computer readable medium of feature (17), wherein the predetermined condition comprises determining whether the current block is encoded in IBC mode.

[0227] (19) A non-volatile computer-readable medium storing instructions which, when executed by a processor in a video decoder, cause the processor to perform a method comprising: receiving an encoded video bitstream including a current picture; retrieving signaling data of the encoded video bitstream for a current block; determining whether the signaling data retrieved for the current block includes a maximum number of merge candidates; and, based on determining whether the signaling data for the current block includes the maximum number of merge candidates, setting a maximum number of intra-block copy (IBC) candidates.

[0228] (20) A non-volatile computer-readable medium according to feature (19), wherein if it is determined that the maximum number of merge candidates is not included in the signaling data, the maximum number of IBC candidates is set to a value between 1 and 6.

Claims

1. A video decoding method, characterized in that: include: Receiving an encoded video bitstream including a current picture; determining, based on signaling data included in the coded video bitstream, a condition specifying whether a maximum number of merge mode candidates is different from a maximum number of intra block copy (IBC) candidates; Based on the determined condition, determining a size of an index included in the signaling data for a vector predictor candidate list to be one of: (i) a maximum number of merge mode candidates and (ii) a maximum number of candidates; Determining the vector prediction value candidate list; retrieving a vector predictor from the vector predictor candidate list according to an index value having a size not exceeding the index; as well as, The current block is decoded according to the retrieved vector prediction value.

2. The method according to claim 1, characterized in that Further including: Determining an initial value of a maximum number of IBC candidates for the current block in the coded video bitstream; If it is determined that the signaled maximum number of merge mode candidates is less than the initial value of the maximum number of IBC candidates for the current block, the maximum number of IBC candidates is determined.

3. The method according to claim 2, characterized in that Further including: If it is determined that the maximum number of merge mode candidates is not signaled for the current block, the maximum number of IBC candidates is determined to be 6.

4. The method according to any one of claims 1 to 3, characterized in that: Further including: Based on whether the slice type of the current block is I, P, or B, a maximum number of the merge mode candidates is determined.

5. The method according to claim 4, characterized in that When the slice type of the current block is P or B, a maximum number of the merge mode candidates is determined.

6. The method according to claim 4, characterized in that When the slice type of the current block is I, it is determined that the maximum number of merge mode candidates is not signaled.

7. A video encoding method, characterized in that: include: determining a condition specifying whether a maximum number of merge mode candidates is different from a maximum number of intra block copy (IBC) candidates for a current block of a current picture; Based on the determined condition, determining a size of an index included in signaling data for a vector predictor candidate list to be one of: (i) a maximum number of merge mode candidates and (ii) a maximum number of candidates, the signaling data indicating the determined condition; Constructing the vector prediction value candidate list; encoding the current block according to the vector prediction value selected from the constructed candidate list; An encoded video bitstream is generated, which includes encoding information of the current block, the signaling data for the current block, and an index value that does not exceed the size of the index and indicates the selected vector prediction value.

8. A method for processing visual media data, characterized in that: include: Conversion between visual media files and visual media data bitstreams is performed according to format rules, wherein The bitstream includes coding information of a current block, including signaling data for the current block, The signaling data indicates whether the maximum number of merge mode candidates is different from the maximum number of intra-block copy (IBC) candidates, and The signaling data comprises an index for selecting a vector predictor from a list of vector predictor candidates, The format rule provides for determining a condition that specifies whether a maximum number of merge mode candidates is different from a maximum number of intra-block copy (IBC) candidates for a current block of a current picture; The format rule specifies that, based on the determined condition, the size of the index included in the signaling data is set to one of: (i) a maximum number of merge mode candidates and (ii) a maximum number of IBC candidates.

9. A video encoding and decoding device, characterized in that: The method comprises a processing circuit for executing the method according to any one of claims 1 to 8.

10. A non-volatile computer readable medium, characterized in that: The non-transitory computer-readable medium stores instructions, and when the instructions are executed by a processor, the processor is caused to perform the method according to any one of claims 1 to 8.

11. A method for processing a video bitstream, characterized in that: The video bit stream is decoded according to the video decoding method according to any one of claims 1 to 6, or is generated based on the video encoding method according to claim 7.

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