Adjustment-Based Local Illumination Compensation

Abstract

Aspects of the present disclosure provide a method and apparatus for video decoding. The apparatus includes a processing circuit that decodes prediction information for one or more blocks including a current block from a coded video bitstream. The prediction information indicates that local illumination compensation (LIC) is applied to the one or more blocks and includes LIC information for the one or more blocks. The processing circuit decodes a final scaling factor α of a first sub-block in the current block based on the LIC information. f1 and the final offset β f1 The processing circuit determines the final scaling factor α f1 , the final offset β f1 , and the first predictor sub-block, determine an updated first predictor sub-block in the predictor corresponding to the current block. The update value of the first sample in the first predictor sub-block is α f1 ×p i1 +β f1 is equal to p i1 is the value of the first sample.

Description

[Technical field]

[0001] Incorporation by Reference This application claims the benefit of priority to U.S. Provisional Application No. 63 / 298,788, entitled "ADJUSTMENT BASED LOCAL ILLUMINATION COMPENSATION," filed on January 12, 2022, which claims the benefit of priority to U.S. Provisional Application No. 17 / 903,697, entitled "ADJUSTMENT BASED LOCAL ILLUMINATION COMPENSATION," filed on September 6, 2022. The disclosures of the prior applications are incorporated herein by reference in their entireties.

[0002] This disclosure describes embodiments related generally to video coding. [Background technology]

[0003] The background discussion provided herein is intended to provide a general context for the present disclosure. The inventors' work, to the extent that it is described in this background section, and aspects of the description that may not be admitted as prior art at the time of filing, are not admitted expressly or impliedly as prior art to the present disclosure.

[0004] Uncompressed digital images and / or videos may include a sequence of pictures, each having spatial dimensions of, for example, 1920x1080 luminance samples and associated chrominance samples. The sequence of pictures may have a fixed or variable picture rate (also informally known as frame rate), for example, 60 pictures per second or 60 Hz. Uncompressed images and / or videos have specific bitrate requirements. For example, 1080p60 4:2:0 video (1920x1080 luminance sample resolution at a frame rate of 60 Hz) with 8 bits per sample requires a bandwidth approaching 1.5 Gbit / s. One hour of such video requires more than 600 GByte of storage space.

[0005] One objective of image and / or video coding and decoding may be the reduction of redundancy in the input image and / or video signal through compression. Compression may help reduce the aforementioned bandwidth and / or storage space requirements, possibly by more than one order of magnitude. The description herein uses video encoding / decoding as an illustrative example, but the same techniques may be applied to image encoding / decoding in a similar manner without departing from the spirit of this disclosure. Both lossless and lossy compression, and combinations thereof, may be employed. Lossless compression refers to techniques where an exact copy of the original signal may be reconstructed from a compressed original signal. When using lossy compression, the reconstructed signal may not be identical to the original signal, but the distortion between the original signal and the reconstructed signal is small enough to make the reconstructed signal useful for the intended application. For video, lossy compression is widely adopted. The amount of acceptable distortion depends on the application, e.g., a user of a particular consumer streaming application may tolerate higher distortion than a user of a television distribution application. The achievable compression ratio may reflect that a higher acceptable / tolerable distortion may result in a higher compression ratio.

[0006] Video encoders and decoders can utilize techniques from a number of broad categories, including, for example, motion compensation, transform processing, quantization, and entropy coding.

[0007] Video codec techniques can include a technique known as intra-coding. In intra-coding, sample values ​​are represented without reference to samples or other data from previously reconstructed reference pictures. In some video codecs, a picture is spatially subdivided into blocks of samples. When all blocks of samples are coded in intra mode, the picture may be an intra picture. Intra pictures and their derivatives, such as independent decoder refresh pictures, can be used to reset the decoder state and therefore can be used as the first picture in a coded video bitstream and video session or as a still image. Samples of an intra block can undergo a transform, and the transform coefficients can be quantized before entropy coding. Intra prediction can be a technique that minimizes sample values ​​in the pre-transform domain. In some cases, the smaller the DC value after the transform and the smaller the AC coefficients, the fewer bits are needed at a given quantization step size to represent the block after entropy coding.

[0008] For example, conventional intra-coding, used in MPEG-2 generation coding techniques, does not use intra-prediction. However, some newer video compression techniques include techniques that attempt to perform prediction based on surrounding sample data and / or metadata obtained during the encoding and / or decoding of a block of data. Such techniques are hereinafter referred to as "intra-prediction" techniques. It should be noted that in at least some cases, intra-prediction uses only reference data from the current picture being reconstructed, and not from a reference picture.

[0009] Intra prediction may take many different forms. When more than one of such techniques may be used in a given video coding technique, the particular technique in use may be coded as a particular intra prediction mode using the particular technique. In certain cases, an intra prediction mode may have sub-modes and / or parameters that may be coded separately or included in a mode codeword that defines the prediction mode used. Which codeword is used for a given mode, sub-mode, and / or parameter combination may affect the coding efficiency gains via intra prediction, and so may the entropy coding technique used to convert the codeword into a bitstream.

[0010] A specific mode of intra prediction was introduced in H.264, improved in H.265, and further improved in newer coding techniques such as Joint Search Model (JEM), Versatile Video Coding (VVC), and Benchmark Set (BMS). A predictor block can be formed using neighboring sample values ​​of already available samples. The sample values ​​of the neighboring samples are copied to the predictor block according to the direction. The reference to the direction in use can be coded in the bitstream or can be predicted itself.

[0011] Referring to FIG. 1A, depicted at the bottom right is a subset of 9 predictor directions known from the 33 possible predictor directions defined in H.265 (corresponding to the 33 angle modes of the 35 intra modes). The point where the arrows converge (101) represents the sample being predicted. The arrows represent the direction in which the sample is predicted. For example, arrow (102) indicates that sample (101) is predicted from one or more samples to the upper right, at an angle of 45 degrees from the horizontal. Similarly, arrow (103) indicates that sample (101) is predicted from one or more samples to the lower left of sample (101), at an angle of 22.5 degrees from the horizontal.

[0012] 1A, a square block (104) of 4×4 samples is shown at the top left (indicated by a dashed bold line). The square block (104) contains 16 samples, each labeled with "S", its position in the Y dimension (e.g., row index), and its position in the X dimension (e.g., column index). For example, sample S21 is the second sample (from the top) in the Y dimension and the first sample (from the left) in the X dimension. Similarly, sample S44 is the fourth sample in both the Y and X dimensions in the block (104). Since the block is 4×4 samples in size, S44 is at the bottom right. Further shown are reference samples that follow a similar numbering scheme. The reference samples are labeled with R, their Y position (e.g., row index), and X position (column index) relative to the block (104). In both H.264 and H.265, the predicted samples are adjacent to the block being reconstructed, and therefore negative values ​​do not need to be used.

[0013] Intra-picture prediction can work by copying reference sample values ​​from adjacent samples indicated by the signaled prediction direction. For example, assume that the coded video bitstream includes signaling for this block indicating a prediction direction that coincides with the arrow (102), i.e., the sample is predicted from the sample to the upper right, at an angle of 45 degrees from the horizontal. In that case, samples S41, S32, S23, S14 are predicted from the same reference sample R05. Then, sample S44 is predicted from reference sample R08.

[0014] In certain cases, especially when the orientation is not evenly divisible by 45 degrees, the values ​​of multiple reference samples may be combined, for example by interpolation, to calculate the reference sample.

[0015] The number of possible directions has increased as video coding techniques have developed. In H.264 (2003), nine different directions could be represented. This increased to 33 in H.265 (2013). Currently, JEM / VVC / BMS can support up to 65 directions. Experiments have been carried out to identify the most likely directions, and certain techniques of entropy coding are used to represent those likely directions with a small number of bits, accepting a certain penalty for less likely directions. Furthermore, in some cases the direction itself can be predicted from neighboring directions used in neighboring, already decoded blocks.

[0016] FIG. 1B shows a schematic diagram (110) showing 65 intra prediction directions with JEM to illustrate the increasing number of prediction directions over time.

[0017] The mapping of intra-prediction direction bits representing directions in the coded video bitstream may vary between video coding techniques. Such mappings may range from simple direct mappings to complex adaptive schemes including codewords, most probable modes, and similar techniques. However, in most cases, there may be certain directions that are statistically less likely to occur in the video content than certain other directions. Since the goal of video compression is to reduce redundancy, these less likely directions are represented by more bits than more likely directions in well-performing video coding techniques.

[0018] Image and / or video coding and decoding can be performed using inter-picture prediction with motion compensation. Motion compensation may be a lossy compression technique and may relate to a technique in which blocks of sample data from a previously reconstructed picture or part thereof (reference picture) are used to predict a newly reconstructed picture or part of a picture after being spatially shifted in a 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, with the third dimension being an indication of the reference picture in use (the latter may indirectly be a temporal dimension).

[0019] In some video compression techniques, the MV applicable to a particular area of ​​sample data can be predicted from other MVs, e.g., from MVs associated with other areas of sample data that are spatially adjacent to the area being reconstructed and that precede that MV in decoding order. Doing so can significantly reduce the amount of data required to code the MV, thereby eliminating redundancy and increasing the compression ratio. MV prediction can work effectively because, for example, when coding an input video signal derived from a camera (known as natural video), there is a statistical likelihood that areas larger than the area to which a single MV is applicable move in similar directions and can therefore, in some cases, be predicted using similar motion vectors derived from MVs of neighboring areas. As a result, the detected MV for a given area is similar or the same as the MV predicted from the surrounding MVs, which can be represented after entropy coding with fewer bits than would be used if the MV were coded directly. In some cases, MV prediction can be an example of lossless compression of a signal (i.e., MV) derived from an original signal (i.e., a sample stream). In other cases, the MV prediction itself can be lossy, e.g., due to rounding errors when calculating a predictor from several surrounding MVs.

[0020] Various MV prediction mechanisms are described in H.265 / HEVC (ITU-T Rec. H.265, "High Efficiency Video Coding", December 2016). Among the many MV prediction mechanisms offered by H.265, one that will be described with reference to Fig. 2 is a technique hereafter referred to as "spatial merging".

[0021] Referring to Figure 2, a current block (201) contains samples that are known by the encoder during the motion search process to be predictable from a previous block of the same size but spatially shifted. Instead of coding its MV directly, the MV can be derived from metadata associated with one or more reference pictures, e.g., the most recent reference picture (in decoding order), using MVs associated with any one of five surrounding samples, denoted A0, A1, and B0, B1, B2 (202-206, respectively). In H.265, MV prediction can use predictors from the same reference picture that neighboring blocks are using. Summary of the Invention [Means for solving the problem]

[0022] Aspects of the present disclosure provide methods and apparatus for video encoding and decoding. In some examples, the apparatus for video decoding includes a processing circuit. The processing circuit is configured to decode prediction information for one or more blocks from a coded video bitstream. The prediction information indicates that local illumination compensation (LIC) is applied to the one or more blocks and includes LIC information for the one or more blocks. The one or more blocks include a current block to be reconstructed. The processing circuit determines a final scaling factor α of a first sub-block in the current block based on the LIC information. f1 and the final offset β of the first subblock in the current block f1 The processing circuit determines the final scaling factor α f1 , the final offset β f1 , and the first predictor sub-block, determine an updated first predictor sub-block in the predictor corresponding to the current block. In one example, the update value of the first sample in the first predictor sub-block in the predictor is α f1 ×p i1 +β f1 is equal to p i1is a value of a first sample in a first predictor sub-block in the predictor. The processing circuit reconstructs a first sub-block in the current block based on the updated first predictor sub-block in the predictor.

[0023] In one embodiment, the initial scaling factor α of the first sub-block in the current block is i1 and the initial offset β of the first subblock in the current block i1 The LIC information for the one or more blocks is signaled in the coded video bitstream, and the first parameter μ for the one or more blocks is determined based on a first portion of the current template for the current block and a first portion of the reference template for the reference block. The predictor can be based on the reference block. The LIC information for the one or more blocks is signaled in the coded video bitstream, and the first parameter μ for the one or more blocks is signaled in the coded video bitstream. 1 and a second parameter μ of one or more blocks 2 The processing circuitry may further include a first parameter μ 1 and the initial scaling coefficient α of the first sub-block in the current block i1 Based on the above, the final scaling coefficient α of the first sub-block in the current block is calculated. f1 The processing circuit determines a second parameter μ of the one or more blocks. 2 and the initial offset β of the first subblock in the current block i1 Based on the,final offset β of the first sub-block in the current block, f1 Determine.

[0024] In one example, the LIC information of one or more blocks includes (i) a first parameter μ 1 and (ii) a second parameter μ 2 (i) the first parameter μ 1 and (ii) a second parameter μ 2 The other is (i) the first parameter μ 1 and (ii) a second parameter μ 2 The determination is based on one of the following:

[0025] In one example, (i) a first parameter μ 1 and (ii) a second parameter μ 2 One of them is equal to zero, and the LIC information of one or more blocks does not indicate (i) the first parameter μ 1 and (ii) the second parameter μ 2 One of them.

[0026] In one example, the LIC information of one or more blocks includes at least one index indicating at least one of the first parameter μ 1 or the second parameter μ 2 .

[0027] In one example, at least one of the first parameter μ 1 or the second parameter μ 2 is a floating - point value, quantized in multiple bits, and the LIC information of one or more blocks includes multiple bits.

[0028] In one example, the processing circuit determines the final scaling coefficient α f1 of the first sub - block in the current block to be the sum of the first parameter μ 1 of one or more blocks and the initial scaling coefficient α i1 of the first sub - block in the current block.

[0029] In one example, the processing circuit determines the parameter T avg,1 of the first sub - block in the current block based on at least one of the first part of the current template or the first part of the reference template, and determines the final offset β f1 of the first sub - block in the current block to be (β i1 +μ 2 ×T avg,1 ).

[0030] In one example, the LIC information of one or more blocks is signaled at the coding unit (CU) level.

[0031] In one example, LIC information for one or more blocks is signaled at a level higher than the CU level.

[0032] In one example, the first sub-block comprises a current block, the first predictor sub-block comprises a predictor, the first portion of the current template comprises a current template, and the first portion of the reference template comprises a reference template.

[0033] In one example, the current block includes a first sub-block and a second sub-block, and a first parameter μ indicated in the LIC information of one or more blocks. 1 or the second parameter μ 2 is applied to the first sub-block and the second sub-block, and the second sub-block is adjusted to an initial scaling factor α i1 Another initial scaling factor α i2 and another initial offset β different from the initial offset of the first sub-block i2 is associated with.

[0034] Aspects of the present disclosure also provide a non-transitory computer-readable storage medium storing a program executable by at least one processor to perform a method for video decoding.

[0035] Further features, nature and various advantages of the disclosed subject matter will become more apparent from the following detailed description and the accompanying drawings. [Brief description of the drawings]

[0036] [Figure 1A] FIG. 2 is a schematic diagram of an example subset of intra-prediction modes. [Figure 1B] FIG. 2 is a diagram of an example intra-prediction direction. [Diagram 2] FIG. 2 is a diagram showing an example of a current block (201) and surrounding samples. [Diagram 3]FIG. 3 is a schematic diagram of an example block diagram of a communication system (300). [Figure 4] FIG. 4 is a schematic diagram of an example block diagram of a communication system (400). [Diagram 5] FIG. 2 is a schematic diagram of an example block diagram of a decoder. [Figure 6] FIG. 2 is a schematic diagram of an example block diagram of an encoder; [Figure 7] FIG. 2 is a block diagram illustrating an example encoder. [Figure 8] FIG. 2 is a block diagram illustrating an exemplary decoder. [Figure 9] FIG. 2 illustrates locations of spatial merge candidates according to one embodiment of the present disclosure. [Figure 10] FIG. 1 illustrates candidate pairs considered for redundancy checking of spatial merge candidates according to one embodiment of the present disclosure. [Figure 11] FIG. 13 illustrates an example motion vector scaling for temporal merge candidates. [Figure 12] A diagram illustrating example candidate positions for temporal merge candidates for a current coding unit. [Figure 13A] FIG. 1 is a diagram illustrating an example of an affine model. [Figure 13B] FIG. 1 is a diagram illustrating an example of an affine model. [Figure 14] FIG. 13 is a diagram illustrating an example of a sub-block based on affine prediction. [Figure 15] FIG. 13 is a diagram showing an example of determining control point motion vector (CPMV) candidates in the affine merge list of a current CU. [Figure 16] FIG. 2 illustrates an example of spatial and temporal neighborhoods of a current block. [Figure 17] FIG. 1 illustrates an example LIC with parameter adjustment. [Figure 18] 1 is a flowchart outlining an encoding process according to one embodiment of the present disclosure. [Figure 19] 1 is a flow chart outlining a decoding process according to one embodiment of the present disclosure. [Figure 20]FIG. 1 is a schematic diagram of a computer system according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] FIG. 3 illustrates an example block diagram of a communication system (300). The communication system (300) includes a plurality of terminal devices that can communicate with each other, for example, via a network (350). For example, the communication system (300) includes a first pair of terminal devices (310) and (320) interconnected via the network (350). In the example of FIG. 3, the first pair of terminal devices (310) and (320) perform unidirectional transmission of data. For example, the terminal device (310) may code video data (e.g., a stream of video pictures captured by the terminal device (310)) for transmission to the other terminal device (320) via the network (350). The encoded video data may be transmitted in the form of one or more coded video bitstreams. The terminal device (320) may receive the coded video data from the network (350), decode the coded video data to reconstruct the video pictures, and display the video pictures according to the reconstructed video data. Unidirectional data transmission may be common, such as in media serving applications.

[0038] In another example, the communication system (300) includes a second pair of terminal devices (330) and (340) performing bidirectional transmission of coded video data, for example during a video conference. In the case of bidirectional transmission of data, in one example, each of the terminal devices (330) and (340) can code video data (e.g., a stream of video pictures captured by the terminal device) for transmission to the other of the terminal devices (330) and (340) over the network (350). Each of the terminal devices (330) and (340) can also receive coded video data transmitted by the other of the terminal devices (330) and (340), can decode the coded video data to recover the video pictures, and can display the video pictures on an accessible display device according to the recovered video data.

[0039] In the example of FIG. 3, the terminal devices (310), (320), (330), and (340) are illustrated as a server, a personal computer, and a smartphone, respectively, although the principles of the present disclosure may not be so limited. The embodiments of the present disclosure apply with laptop computers, tablet computers, media players, and / or dedicated video conferencing equipment. The network (350) represents any number of networks that convey coded video data between the terminal devices (310), (320), (330), and (340), including, for example, wired (wired) and / or wireless communication networks. The communication network (350) may exchange data over circuit-switched channels and / or packet-switched channels. Representative networks include telecommunications networks, local area networks, wide area networks, and / or the Internet. For purposes of this description, the architecture and topology of the network (350) may not be important to the operation of the present disclosure unless otherwise described herein below.

[0040] 4 shows a video encoder and video decoder in a streaming environment as an example of an application for the disclosed subject matter. The disclosed subject matter may be equally applicable to other video-enabled applications including, for example, video conferencing, digital television, streaming services, storage of compressed video on digital media including CDs, DVDs, memory sticks, etc.

[0041] The streaming system may include a video source (401), e.g., a capture subsystem (413) that may include, e.g., a digital camera, that creates a stream of uncompressed video pictures (402). In one example, the stream of video pictures (402) includes samples taken by a digital camera. The stream of video pictures (402), depicted as a thick line to emphasize the larger amount of data when compared to the encoded video data (404) (or coded video bitstream), may be processed by an electronic device (420) that includes a video encoder (403) connected to the video source (401). The video encoder (403) may include hardware, software, or a combination thereof to enable or implement aspects of the disclosed subject matter, as described in more detail below. The encoded video data (404) (or coded video bitstream), depicted as a thin line to emphasize the smaller amount of data when compared to the stream of video pictures (402), may be stored in a streaming server (405) for future use. One or more streaming client subsystems, such as the client subsystems (406) and (408) of FIG. 4, can access the streaming server (405) to retrieve copies (407) and (409) of the encoded video data (404). The client subsystem (406) can include a video decoder (410), for example, within an electronic device (430). The video decoder (410) decodes an input copy (407) of the encoded video data and creates an output stream (411) of video pictures that can be rendered on a display (412) (e.g., a display screen) or other rendering device (not shown). In some streaming systems, the encoded video data (404), (407), and (409) (e.g., a video bitstream) can be encoded according to a particular video coding / compression standard. Examples of these standards include ITU-T Recommendation H.265. In one example, a video coding standard under development is informally known as Versatile Video Coding (VVC).The disclosed subject matter may be used in the context of a VVC.

[0042] It should be noted that the electronic devices (420) and (430) may include other components (not shown). For example, the electronic device (420) may include a video decoder (not shown), and the electronic device (430) may also include a video encoder (not shown).

[0043] 5 shows an example block diagram of a video decoder (510). The video decoder (510) may be included in an electronic device (530). The electronic device (530) may include a receiver (531) (e.g., a receiving circuit). The video decoder (510) may be used in place of the video decoder (410) of the example of FIG.

[0044] The receiver (531) may receive one or more coded video sequences to be decoded by the video decoder (510). In one embodiment, one coded video sequence is received at a time, and the decoding of each coded video sequence is independent of the decoding of the other coded video sequences. The coded video sequences may be received from a channel (501), which may be a hardware / software link to a storage device that stores the coded video data. The receiver (531) may receive the coded video data along with other data, such as a coded audio data stream and / or an auxiliary data stream, which may be forwarded to a respective usage entity (not shown). The receiver (531) may separate the coded video sequences from the other data. To combat network jitter, a buffer memory (515) may be connected between the receiver (531) and the entropy decoder / parser (520) (hereinafter "parser (520)"). In certain applications, the buffer memory (515) is part of the video decoder (510). In other applications, the buffer memory (515) may be external to the video decoder (510) (not shown). In still other applications, there may be a buffer memory (not shown) external to the video decoder (510), e.g., to combat network jitter, plus another buffer memory (515) internal to the video decoder (510), e.g., to handle playout timing. When the receiver (531) is receiving data from a storage / forwarding device with sufficient bandwidth and controllability, or from an isosynchronous network, the buffer memory (515) may be unnecessary or may be small. For use with best-effort packet networks such as the Internet, the buffer memory (515) may be required and may be relatively large, advantageously of adaptive size, and may be implemented at least in part in an operating system or similar element (not shown) external to the video decoder (510).

[0045] The video decoder (510) may include a parser (520) to reconstruct symbols (521) from the coded video sequence. These categories of symbols include information used to manage the operation of the video decoder (510) and potentially information for controlling a rendering device such as a rendering device (512) (e.g., a display screen) that is not an integral part of the electronic device (530) but may be connected to the electronic device (530) as shown in FIG. 5. The control information for the rendering device(s) may be in the form of a Supplemental Enhancement Information (SEI) message or a Video Usability Information (VUI) parameter set fragment (not depicted). The parser (520) may parse / entropy decode the received coded video sequence. The coding of the coded video sequence may follow a video coding technique or standard and may follow various principles including variable length coding with or without context dependency, Huffman coding, arithmetic coding, etc. The parser (520) may extract, from the coded video sequence, a set of subgroup parameters for at least one of the subgroups of pixels in the video decoder based on at least one parameter corresponding to the group. The subgroups may include groups of pictures (GOPs), pictures, tiles, slices, macroblocks, coding units (CUs), blocks, transform units (TUs), prediction units (PUs), etc. The parser (520) may also extract information from the coded video sequence, such as transform coefficients, quantization parameter values, motion vectors, etc.

[0046] The parser (520) may perform entropy decoding / parsing operations on the video sequence received from the buffer memory (515) to produce symbols (521).

[0047] The reconstruction of the symbols (521) may involve several different units, depending on the type of coded video picture or portion thereof (inter-picture and intra-picture, inter-block and intra-block, etc.), as well as other factors. Which units are involved and how may be controlled by subgroup control information parsed from the coded video sequence by the parser (520). The flow of such subgroup control information between the parser (520) and the following units is not depicted for clarity.

[0048] Beyond the functional blocks already mentioned, the video decoder (510) may be conceptually subdivided into several functional units, as described below. In an actual implementation operating under commercial constraints, many of these units may interact closely with each other and may be, at least in part, integrated with each other. However, for purposes of describing the disclosed subject matter, the following conceptual subdivision into functional units is appropriate:

[0049] The first unit is a scalar / inverse transform unit (551), which receives quantized transform coefficients as well as control information including which transform to use, block size, quantization coefficients, quantization scaling matrices, etc. as symbol(s) (521) from the parser (520). The scalar / inverse transform unit (551) can output blocks containing sample values ​​that can be input to an aggregator (555).

[0050] In some cases, the output samples of the scaler / inverse transform unit (551) may relate to intra-coded blocks. Intra-coded blocks are blocks that do not use prediction information from a previously reconstructed picture, but can use prediction information from a previously reconstructed portion of the current picture. Such prediction information may be provided by an intra-picture prediction unit (552). In some cases, the intra-picture prediction unit (552) generates a block of the same size and shape as the block being reconstructed using surrounding already reconstructed information fetched from the current picture buffer (558). The current picture buffer (558) buffers, for example, the partially reconstructed and / or the fully reconstructed current picture. The aggregator (555) adds, possibly on a sample-by-sample basis, the prediction information generated by the intra-prediction unit (552) to the output sample information provided by the scaler / inverse transform unit (551).

[0051] In other cases, the output samples of the scalar / inverse transform unit (551) may relate to an inter-coded, potentially motion-compensated block. In such cases, the motion compensated prediction unit (553) may access the reference picture memory (557) to fetch samples used for prediction. After motion compensating the fetched samples according to the symbols (521) related to the block, these samples may be added to the output of the scalar / inverse transform unit (551) by the aggregator (555) to generate output sample information (in this case referred to as residual samples or residual signals). The addresses in the reference picture memory (557) from which the motion compensated prediction unit (553) fetches the prediction samples may be controlled by motion vectors available to the motion compensated prediction unit (553) in the form of symbols (521), which may have, for example, X, Y, and reference picture components. Motion compensation may also include interpolation of sample values ​​fetched from the reference picture memory (557) when sub-sample accurate motion vectors are used, motion vector prediction mechanisms, etc.

[0052] The output samples of the aggregator (555) may be subjected to various loop filtering techniques in a loop filter unit (556). Video compression techniques may include in-loop filter techniques controlled by parameters contained in the coded video sequence (also called a coded video bitstream) and provided to the loop filter unit (556) as symbols (521) from the parser (520). Video compression may also be performed in response to meta-information obtained during decoding of a previous portion (in decoding order) of the coded picture or coded video sequence, or in response to previously reconstructed and loop filtered sample values.

[0053] The output of the loop filter unit (556) may be a sample stream that can be stored in a reference picture memory (557) for use in future inter-picture prediction as well as output to a rendering device (512).

[0054] Once a particular coded picture is fully reconstructed, it can be used as a reference picture for future prediction. For example, once a coded picture corresponding to a current picture is fully reconstructed and the coded picture is identified as a reference picture (e.g., by the parser (520)), the current picture buffer (558) can become part of the reference picture memory (557), and a new current picture buffer can be reallocated before beginning reconstruction of the next coded picture.

[0055] The video decoder (510) may perform decoding operations according to a given video compression technique or standard, such as ITU-T Rec. H.265. The coded video sequence may conform to the syntax specified by the video compression technique or standard used in the sense that the coded video sequence adheres to both the syntax of the video compression technique or standard and the profile documented in the video compression technique or standard. Specifically, the profile may select a particular tool from all tools available in the video compression technique or standard as the only tool available under that profile. Also, what is required for compliance may be that the complexity of the coded video sequence is within a range defined by the level of the video compression technique or standard. In some cases, the level limits the maximum picture size, maximum frame rate, maximum reconstruction sample rate (e.g., measured in megasamples per second), maximum reference picture size, etc. The limits set by the level may be further limited in some cases by the specification of a hypothetical reference decoder (HRD) and metadata for HRD buffer management signaled within the coded video sequence.

[0056] In one embodiment, the receiver (531) can receive additional (redundant) data along with the encoded video. The additional data may be included as part of the coded video sequence(s). The additional data may be used by the video decoder (510) to properly decode the data and / or to 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.

[0057] 6 shows an example block diagram of a video encoder (603). The video encoder (603) is included in an electronic device (620). The electronic device (620) includes a transmitter (640) (e.g., a transmitting circuit). The video encoder (603) can be used in place of the video encoder (403) of the example of FIG.

[0058] The video encoder (603) may receive video samples from a video source (601) (which is not part of the electronic device (620) in the example of FIG. 6) that may capture video images to be coded by the video encoder (603). In another example, the video source (601) is part of the electronic device (620).

[0059] The video source (601) may provide a source video sequence to be coded by the video encoder (603) in the form of a digital video sample stream that may be of 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 serving system, the video source (601) may be a storage device that stores pre-prepared footage. In a video conferencing system, the video source (601) may be a camera that captures local image information as a video sequence. The video data may be provided as multiple individual pictures that convey motion when viewed in sequence. The pictures themselves may be organized as a spatial array of pixels, each of which may contain one or more samples, depending on the sampling structure, color space, etc., in use. Those skilled in the art may easily understand the relationship between pixels and samples. The following description focuses on samples.

[0060] According to one embodiment, the video encoder (603) may code and compress pictures of a source video sequence into a coded video sequence (643) in real time or under any other time constraints required. Enforcing an appropriate coding rate is one function of the controller (650). In some embodiments, the controller (650) controls and is operatively connected to other functional units described below. For clarity, connections are not drawn. Parameters set by the controller (650) may include rate control related parameters (picture skip, quantizer, lambda value for rate distortion optimization techniques, ...), picture size, group of pictures (GOP) layout, maximum motion vector search range, etc. The controller (650) may be configured with other appropriate functions related to the video encoder (603) optimized for a particular system design.

[0061] In some embodiments, the video encoder (603) is configured to operate in a coding loop. As an oversimplified explanation, in one example, the coding loop can include a source coder (630) (e.g., responsible for creating symbols, such as a symbol stream, based on an input picture to be coded and a reference picture(s)) and a (local) decoder (633) embedded in the video encoder (603). The decoder (633) reconstructs the symbols to create sample data in a similar manner that a (remote) decoder would also create. The reconstructed sample stream (sample data) is input to a reference picture memory (634). Since the decoding of the symbol stream results in bit-exact results regardless of the location of the decoder (local or remote), the contents of the reference picture memory (634) are also bit-exact between the local and remote encoders. In other words, the predictive part of the encoder "sees" exactly the same sample values ​​as the decoder would "see" when using prediction during decoding as reference picture samples. This basic principle of reference picture synchrony (and the resulting drift when synchrony cannot be maintained, for example due to channel error) is also used in several related techniques.

[0062] The operation of the "local" decoder (633) may be the same as the operation of a "remote" decoder, such as the video decoder (510), already described in detail above in conjunction with Figure 5. However, with brief reference also to Figure 5, because symbols are available and the encoding / decoding of symbols into a coded video sequence by the entropy coder (645) and parser (520) may be lossless, the entropy decoding portion of the video decoder (510), including the buffer memory (515), and the parser (520), may not be fully implemented in the local decoder (633).

[0063] In one embodiment, the decoder techniques, except for parsing / entropy decoding, present in the decoder are present in the same or substantially the same functional form in the corresponding encoder. Thus, the disclosed subject matter focuses on the operation of the decoder. A description of the encoder techniques can be omitted, since they are the inverse of the decoder techniques described generically. In certain areas, more detailed descriptions are provided below.

[0064] In operation, in some examples, the source coder (630) may perform motion-compensated predictive coding, which predictively codes an input picture with reference to one or more previously coded pictures from a video sequence designated as “reference pictures.” In this manner, the coding engine (632) codes differences between pixel blocks of the input picture and pixel blocks of the reference picture(s) that may be selected as the predictive reference(s) to the input picture.

[0065] The local video decoder (633) may decode the coded video data of the pictures that may be designated as reference pictures based on the symbols created by the source coder (630). The operation of the coding engine (632) may advantageously be a lossy process. When the coded video data may be decoded in a video decoder (not shown in FIG. 6), the reconstructed video sequence may be a copy of the source video sequence, usually with some errors. The local video decoder (633) may replicate the decoding process that may be performed by the video decoder on the reference pictures and store the reconstructed reference pictures in the reference picture memory (634). In this way, the video encoder (603) may locally store copies of reconstructed reference pictures that have common content as the reconstructed reference pictures that will be obtained by the far-end video decoder (without transmission errors).

[0066] The predictor (635) may perform a prediction search for the coding engine (632). That is, for a new picture to be coded, the predictor (635) may search the reference picture memory (634) for sample data (as candidate reference pixel blocks) or specific metadata such as reference picture motion vectors, block shapes, etc., that can serve as suitable prediction references for the new pixels. The predictor (635) may operate on sample blocks for each pixel block to find a suitable prediction reference. In some cases, the input picture may have prediction references drawn from multiple reference pictures stored in the reference picture memory (634), as determined by the search results obtained by the predictor (635).

[0067] The controller (650) may manage the coding operations of the source coder (630), including, for example, setting the parameters and subgroup parameters used to encode the video data.

[0068] The output of all the aforementioned functional units may undergo entropy coding in an entropy coder (645), which converts the symbols produced by the various functional units into a coded video sequence by applying lossless compression to the symbols according to techniques such as Huffman coding, variable length coding, arithmetic coding, etc.

[0069] The transmitter (640) may buffer the coded video sequence(s) created by the entropy coder (645) in preparation for transmission over a communication channel (660), which may be a hardware / software link to a storage device that will store the encoded video data. The transmitter (640) may merge the coded video data from the video encoder (603) with other data to be transmitted, such as coded audio data and / or auxiliary data streams (sources not shown).

[0070] The controller (650) may manage the operation of the video encoder (603). During coding, the controller (650) may assign a particular coded picture type to each coded picture, which may affect the coding techniques that may be applied to the respective picture. For example, pictures may often be assigned as one of the following picture types:

[0071] An intra picture (I-picture) may be one that can be coded and decoded without using other pictures in a sequence as a source of prediction. 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 these variations of I-pictures and their respective uses and characteristics.

[0072] A predictive picture (P picture) may be a picture that can be coded and decoded using intra- or inter-prediction, which uses at most one motion vector and reference index to predict sample values ​​for each block.

[0073] A bidirectionally predicted picture (B-picture) may be a picture that can be coded and decoded using intra- or inter-prediction, which uses up to two motion vectors and reference indices to predict the sample values ​​of each block. Similarly, a multi-predicted picture may use more than two reference pictures and associated metadata for the reconstruction of a single block.

[0074] A source picture may generally be spatially subdivided into multiple sample blocks (e.g., blocks of 4x4, 8x8, 4x8, or 16x16 samples each) and coded block by block. A block may be predictively coded with reference to other (already coded) blocks determined by the coding assignment applied to the block's respective picture. For example, a block of an I picture may be non-predictively coded or predictively coded with reference to already coded blocks of the same picture (spatial or intra prediction). A pixel block of a P picture may be predictively coded via spatial prediction with reference to one previously coded reference picture or via temporal prediction. A block of a B picture may be predictively coded via spatial prediction or via temporal prediction with reference to one or two previously coded reference pictures.

[0075] The video encoder (603) may perform coding operations in accordance with a given video coding technique or standard, such as ITU-T Recommendation H.265. In its operations, the video encoder (603) may perform various compression operations, including predictive coding operations that exploit temporal and spatial redundancy in the input video sequence. Thus, the coded video data may conform to a syntax specified by the video coding technique or standard being used.

[0076] In one embodiment, the transmitter (640) may transmit additional data along with the encoded video. The source coder (630) may include such data as part of the coded video sequence. The additional data may include temporal / spatial / SNR enhancement layers, other forms of redundant data such as redundant pictures and slices, SEI messages, VUI parameter set fragments, etc.

[0077] A video may be captured in time sequence as multiple source pictures (video pictures). Intra-picture prediction (often abbreviated as intra-prediction) exploits spatial correlation within a given picture, while inter-picture prediction exploits (temporal or other) correlation between pictures. In one example, a particular picture being encoded / decoded, called the current picture, is divided into blocks. When a block in the current picture is similar to a reference block in a previously coded, still buffered reference picture in the video, the block in the current picture may be coded by a vector called a motion vector. A motion vector points to a reference block in a reference picture, and may have a third dimension that identifies the reference picture if multiple reference pictures are used.

[0078] In some embodiments, inter-picture prediction may use a bi-prediction technique. According to the bi-prediction technique, two reference pictures, such as a first reference picture and a second reference picture, are used, both of which are before the current picture in the video in decoding order (but may be past and future in display order, respectively). A block in the current picture may be coded by a first motion vector that points to a first reference block in the first reference picture and a second motion vector that points to a second reference block in the second reference picture. A block may be predicted by a combination of the first reference block and the second reference block.

[0079] Furthermore, merge mode techniques can be used in inter-picture prediction to improve coding efficiency.

[0080] According to some embodiments of the present disclosure, predictions such as inter-picture prediction and intra-picture prediction are performed on a block-by-block basis. For example, according to the HEVC standard, a picture in a sequence of video pictures is divided into coding tree units (CTUs) for compression, and the CTUs in a picture have the same size, such as 64×64 pixels, 32×32 pixels, 16×16 pixels, etc. In general, a CTU includes three coding tree blocks (CTBs), which are one luma CTB and two chroma CTBs. Each CTU can be recursively quadtree partitioned into one or more coding units (CUs). For example, a CTU of 64×64 pixels can be partitioned into one CU of 64×64 pixels, or into four CUs of 32×32 pixels, or into 16 CUs of 16×16 pixels. In one example, each CU is analyzed to determine the prediction type of the CU, such as an inter prediction type or an intra prediction type. A CU is divided into one or more prediction units (PUs) according to temporal predictability and / or spatial predictability. In general, each PU includes one luma prediction block (PB) and two chroma PBs. In one embodiment, the prediction operation in coding (encoding / decoding) is performed in units of prediction blocks. Taking a luma prediction block as an example of a prediction block, the prediction block includes a matrix of pixel values ​​(e.g., luma values) of 8×8 pixels, 16×16 pixels, 8×16 pixels, 16×8 pixels, etc.

[0081] 7 shows an example diagram of a video encoder (703). The video encoder (703) is configured to receive a processed block of sample values ​​(e.g., a predictive block) in a current video picture in a sequence of video pictures and encode the processed block into a coded picture that is part of a coded video sequence. In one example, the video encoder (703) is used in place of the video encoder (403) of the example of FIG. 4.

[0082] In an HEVC example, the video encoder (703) receives a matrix of sample values ​​for a processing block, such as a predictive block of 8×8 samples. The video encoder (703) determines whether the processing block is best coded using intra-mode, inter-mode, or bi-predictive mode, for example using rate-distortion optimization. If the processing block is to be coded in intra-mode, the video encoder (703) may encode the processing block into a coded picture using intra-prediction techniques, and if the processing block is to be coded in inter-mode or bi-predictive mode, the video encoder (703) may encode the processing block into a coded picture using inter-prediction techniques or bi-prediction techniques, respectively. In certain video coding techniques, the merge mode may be an inter-picture prediction sub-mode in which a motion vector is derived from one or more motion vector predictors without the aid of coded motion vector components outside the predictors. In certain other video coding techniques, there may be motion vector components applicable to the current block. In one example, the video encoder (703) includes other components, such as a mode decision module (not shown), to determine the mode of the processing block.

[0083] In the example of FIG. 7, the video encoder (703) includes an inter-encoder (730), an intra-encoder (722), a residual calculator (723), a switch (726), a residual encoder (724), a general controller (721), and an entropy encoder (725), connected to each other as shown in FIG. 7.

[0084] The inter-encoder (730) is configured to receive samples of a current block (e.g., a processing block), compare the block to one or more reference blocks in a reference picture (e.g., blocks in a previous picture and a subsequent picture), generate inter-prediction information (e.g., a description of redundancy information, motion vectors, merge mode information according to an inter-coding technique), and calculate an inter-prediction result (e.g., a prediction block) based on the inter-prediction information using any suitable technique. In some examples, the reference picture is a decoded reference picture that is decoded based on the encoded video information.

[0085] The intra encoder (722) is configured to receive samples of a current block (e.g., a processing block), possibly compare the block to already coded blocks in the same picture, generate transformed quantized coefficients, and possibly also generate intra prediction information (e.g., intra prediction direction information according to one or more intra encoding techniques). In one example, the intra encoder (722) also calculates intra prediction results (e.g., prediction blocks) based on the intra prediction information and reference blocks in the same picture.

[0086] The generic controller (721) is configured to determine generic control data and control other components of the video encoder (703) based on the generic control data. In one example, the generic controller (721) determines the mode of the block and provides a control signal to the switch (726) based on the mode. For example, when the mode is an intra mode, the generic controller (721) controls the switch (726) to select an intra mode result for use by the residual calculator (723) and controls the entropy encoder (725) to select intra prediction information and include the intra prediction information in the bitstream, and when the mode is an inter mode, the generic controller (721) controls the switch (726) to select an inter prediction result for use by the residual calculator (723) and controls the entropy encoder (725) to select inter prediction information and include the inter prediction information in the bitstream.

[0087] The residual calculator (723) is configured to calculate a difference (residual data) between the received block and a prediction result selected from the intra-encoder (722) or the inter-encoder (730). The residual encoder (724) is configured to operate based on the residual data to encode the residual data to generate transform coefficients. In one example, the residual encoder (724) is configured to transform the residual data from the spatial domain to the frequency domain to generate transform coefficients. The transform coefficients then undergo a quantization process to obtain quantized transform coefficients. In various embodiments, the video encoder (703) also includes a residual decoder (728). The residual decoder (728) is configured to perform an inverse transform and generate decoded residual data. The decoded residual data can be used by the intra-encoder (722) and the inter-encoder (730) as appropriate. For example, the inter-encoder (730) can generate decoded blocks based on the decoded residual data and the inter-prediction information, and the intra-encoder (722) can generate decoded blocks based on the decoded residual data and the intra-prediction information. The decoded blocks are appropriately processed to generate decoded pictures, which may be buffered in a memory circuit (not shown) and used as reference pictures in some examples.

[0088] The entropy encoder (725) is configured to format a bitstream to include the encoded block. The entropy encoder (725) is configured to include various information in the bitstream according to an appropriate standard, such as the HEVC standard. In one example, the entropy encoder (725) is configured to include in the bitstream general control data, selected prediction information (e.g., intra-prediction information or inter-prediction information), residual information, and other appropriate information. It should be noted that, according to the disclosed subject matter, no residual information is present when coding a block in a merged sub-mode of either the inter-mode or the bi-prediction mode.

[0089] 8 shows an example diagram of a video decoder (810). The video decoder (810) is configured to receive coded pictures that are part of a coded video sequence and decode the coded pictures to generate reconstructed pictures. In one example, the video decoder (810) is used in place of the video decoder (410) of the example of FIG. 4.

[0090] In the example of FIG. 8, the video decoder (810) includes an entropy decoder (871), an inter decoder (880), a residual decoder (873), a reconstruction module (874), and an intra decoder (872), connected together as shown in FIG. 8.

[0091] The entropy decoder (871) may be configured to reconstruct from the coded picture certain symbols representing syntax elements of which the coded picture is composed. Such symbols may include, for example, prediction information (e.g., intra-mode, inter-mode, bi-predictive mode, inter-mode and bi-predictive mode of merged or other submodes, etc.) that may identify the mode in which the block is coded, as well as certain samples or metadata used for prediction by the intra-decoder (872) or the inter-decoder (880), respectively (e.g., intra-predictive information or inter-predictive information, etc.). The symbols may also include, for example, residual information in the form of quantized transform coefficients, etc. In one example, if the prediction mode is an inter-mode or bi-predictive mode, the inter-predictive information is provided to the inter-decoder (880), and if the prediction type is an intra-predictive type, the intra-predictive information is provided to the intra-decoder (872). The residual information may undergo inverse quantization and is provided to the residual decoder (873).

[0092] The inter decoder (880) is configured to receive the inter prediction information and to generate inter prediction results based on the inter prediction information.

[0093] The intra decoder (872) is configured to receive the intra prediction information and to generate a prediction result based on the intra prediction information.

[0094] The residual decoder (873) is configured to perform inverse quantization to extract inverse quantized transform coefficients, and to process the inverse quantized transform coefficients to transform the residual information from the frequency domain to the spatial domain. The residual decoder (873) may also require certain control information (to include quantization parameters (QPs)), which may be provided by the entropy decoder (871) (this may be only a small amount of control information, so a data path is not depicted).

[0095] The reconstruction module (874) is configured to combine, in the spatial domain, the residual information output by the residual decoder (873) and the prediction results (possibly output by the inter prediction module or the intra prediction module) to form reconstructed blocks that may become part of a reconstructed picture, which may become part of a reconstructed video. It should be noted that other suitable operations, such as a deblocking operation, may be performed to improve visual quality.

[0096] It should be noted that the video encoders (403), (603), and (703) and the video decoders (410), (510), and (810) may be implemented using any suitable technology. In one embodiment, the video encoders (403), (603), and (703) and the video decoders (410), (510), and (810) may be implemented using one or more integrated circuits. In another embodiment, the video encoders (403), (603), and (603) and the video decoders (410), (510), and (810) may be implemented using one or more processors executing software instructions.

[0097] Various inter prediction modes can be used in VVC. For an inter predicted CU, the motion parameters can include MV(s), one or more reference picture indexes, reference picture list usage index, and additional information about the specific coding features to be used for inter predicted sample generation. The motion parameters can be signaled explicitly or implicitly. If a CU is coded in skip mode, the CU can be associated with a PU and may not have significant residual coefficients, coded motion vector deltas, MV differences (e.g. MVD), or reference picture indexes. A merge mode can be specified when the motion parameters of the current CU are obtained from neighboring CU(s) including spatial and / or temporal candidates, and optionally additional information as introduced in VVC. The merge mode can be applied not only to skip mode, but also to inter predicted CUs. In one example, an alternative to the merge mode is explicit transmission of motion parameters, in which the MV(s), the corresponding reference picture index of each reference picture list, and a reference picture list usage flag and other information are explicitly signaled for each CU.

[0098] In one embodiment, such as VVC, the VVC Test Model (VTM) reference software includes one or more improved inter-prediction coding tools, including enhanced merge prediction, merge motion vector differential (MMVD) mode, adaptive motion vector prediction with symmetric MVD signaling (AMVP) mode, affine motion compensation prediction, subblock-based temporal motion vector prediction (SbTMVP), adaptive motion vector resolution (AMVR), motion field storage (1 / 16 luma sample MV storage and 8x8 motion field compression), bi-prediction with CU level weights (BCW), bidirectional optical flow (BDOF), prediction refinement with optical flow (PROF), decoder-side motion vector refinement (DMVR), combined inter and intra prediction (CIIP), geometric partition mode (GPM), etc. Inter prediction and related methods are described in detail below.

[0099] In some examples, enhanced merge prediction may be used. In one example, such as VTM4, a merge candidate list is constructed by including five types of candidates in order: spatial motion vector predictor (MVP)(s) from spatially adjacent CU(s), temporal MVP(s) from ordered CU(s), history-based MVP(s) from a first-in-first-out (FIFO) table, pairwise average MVP(s), and zero MV(s).

[0100] The size of the merge candidate list may be signaled in the slice header. In one example, the maximum allowed size of the merge candidate list is 6 in VTM4. For each CU coded in merge mode, the index of the best merge candidate (e.g., merge index) may be coded using truncated unary binarization (TU). The first bin of the merge index may be coded with context (e.g., context-adaptive binary arithmetic coding (CABAC)) and bypass coding may be used for the other bins.

[0101] Some examples of the generation process of merge candidates of different categories are provided below. In one embodiment, spatial candidate(s) are derived as follows: The derivation of spatial merge candidates in VVC etc. may be the same as that of HEVC. In one example, up to four merge candidates are selected from among the candidates located at the positions shown in FIG. 9. FIG. 9 shows the positions of spatial merge candidates according to one embodiment of the present disclosure. With reference to FIG. 9, the derivation order is B1, A1, B0, A0, and B2. Position B2 is only considered when none of the CUs at positions A0, B0, B1, and A1 are available or intra-coded (e.g., because the CU belongs to another slice or another tile). After the candidate at position A1 is added, the addition of the remaining candidates undergoes a redundancy check that ensures that candidates with the same motion information are excluded from the candidates so that coding efficiency is improved.

[0102] In order to reduce computational complexity, in some embodiments, not all possible candidate pairs are considered in the mentioned redundancy check. Instead, only certain pairs, such as those connected with arrows in FIG. 10, are considered, and a candidate is added to the candidate list only if the corresponding candidates used in the redundancy check do not have the same motion information. FIG. 10 illustrates candidate pairs considered for spatial merge candidate redundancy check according to one embodiment of the present disclosure. With reference to FIG. 10, each arrow-connected pair includes A1 and B1, A1 and A0, A1 and B2, B1 and B0, and B1 and B2. Thus, candidates at positions B1, A0, and / or B2 can be compared with candidates at positions A1, and candidates at positions B0 and / or B2 can be compared with candidates at positions B1.

[0103] In one embodiment, the temporal candidate(s) are derived as follows: In one example, only one temporal merge candidate is added to the candidate list. FIG. 11 shows an example motion vector scaling of a temporal merge candidate. To derive a temporal merge candidate for a current CU (1111) in a current picture (1101), a scaled MV (1121) (e.g., shown by the dotted line in FIG. 11) may be derived based on a co-located CU (1112) belonging to a collocated reference picture (1104). The reference picture list used to derive the co-located CU (1112) may be explicitly signaled in the slice header. The scaled MV (1121) for the temporal merge candidate may be obtained as shown by the dotted line in FIG. 11. The scaled MV (1121) may be scaled from the MV of the co-located CU (1112) using picture order count (POC) distances tb and td. The POC distance tb may be defined as the POC difference between the current reference picture (1102) of the current picture (1101) and the current picture (1101). The POC distance td may be defined as the POC difference between the co-located reference picture (1104) of the co-located picture (1103) and the co-located picture (1103). The reference picture index of the temporal merge candidate may be set to zero.

[0104] FIG. 12 shows exemplary candidate positions (e.g., C0 and C1) of a temporal merge candidate for a current CU. The position of the temporal merge candidate may be selected between candidate positions C0 and C1. Candidate position C0 is located at the bottom right corner of the colocated CU (1210) of the current CU. Candidate position C1 is located at the center of the colocated CU (1210) of the current CU (1210). If the CU at candidate position C0 is not available, is intra-coded, or is outside the current row of the CTU, then candidate position C1 is used to derive the temporal merge candidate. Otherwise, for example, the CU at candidate position C0 is available, is intra-coded, and is in the current row of the CTU, and candidate position C0 is used to derive the temporal merge candidate.

[0105] In some examples, a translational motion model is applied to motion compensated prediction (MCP). However, the translational motion model may not be suitable for modeling zoom in / out, rotation, perspective motion, and other irregular motion. In some embodiments, a block-based affine transformation motion compensated prediction is applied. In FIG. 13A, the affine motion field of a block is described by two control point motion vectors (CPMVs), CPMV0 and CPMV1, for two control points (CPs), CP0 and CP1, when a four-parameter affine model is used. In FIG. 13B, the affine motion field of a block is described by three CPMVs, CPMV0, CPMV1, and CPMV3, for CPs, CP0, CP1, and CP2, when a six-parameter affine model is used.

[0106] In the four-parameter affine motion model, the motion vector at a sample position (x,y) within a block is derived as follows:

number

[0107] In the six-parameter affine motion model, the motion vector at a sample position (x,y) within a block is derived as follows:

number

[0108] In formulas 1 and 2, (mv 0x ,mv 0y ) is the motion vector of the upper left corner control point, and (mv 1x ,mv 1y ) is the motion vector of the bottom-left corner control point, and (mv 2x ,mv 2y ) is the motion vector of the lower-left corner control point. In addition, the coordinates (x,y) are relative to the upper-left corner of each block, and W and H indicate the width and height of each block.

[0109] To simplify the motion compensation prediction, in some embodiments, sub-block-based affine transformation prediction is applied. For example, in FIG. 14, a four-parameter affine motion model is used, and two CPMVs are used.

number

[0110] Similar to translational motion inter prediction, in some embodiments, two affine motion inter prediction modes are employed: affine merge mode and affine AMVP mode.

[0111] In some embodiments, for CUs whose width and height are both 8 or more, an affine merge mode may be applied. Affine merge candidates for the current CU may be generated based on the motion information of spatially neighboring CUs. There may be up to five affine merge candidates, and an index is signaled to indicate the one to be used for the current CU. For example, the following three types of affine merge candidates are used to form the affine merge candidate list: (i) Inherited affine merge candidates extrapolated from the CPMVs of neighboring CUs; (ii) Construct affine merge candidates derived using the translational MVs of neighboring CUs; ​​and (iii) Zero MV.

[0112] In some embodiments, there may be at most two inheritance affine candidates derived from the affine motion models of the neighboring blocks, one from the left neighboring CU and the other from the top neighboring CU. The candidate blocks may be located, for example, at the positions shown in FIG. 9. In the left predictor, the scanning order is A0>A1, and in the top predictor, the scanning order is B0>B1>B2. Only the first inheritance candidate from each side is selected. No pruning check is performed between the two inheritance candidates.

[0113] Once the neighboring affine CUs are identified, the CPMVs of the identified neighboring affine CUs are used to derive the CPMVs in the affine merge list of the current CU. As shown in Figure 15, the bottom-left neighboring block A of the current CU (1510) is coded in affine mode. The motion vectors of the top-left, top-right, and bottom-left corners of the CU (1520) containing block A are

number

number

number

number

[0114] A constructed affine candidate is constructed by combining the neighboring translational motion information of each control point. The motion information of the control points is derived from the specified spatial and temporal neighborhoods shown in FIG. 16. CPMVk (k=1,2,3,4) represents the kth control point. In CPMV1, B2>B3>A2 blocks are checked in order, and the MV of the first available block is used. In CPMV2, B1>B0 blocks are checked, and in CPMV3, A1>A0 blocks are checked. The TMVP in block T is used as CPMV4 if available.

[0115] After the MVs of the four control points are achieved, affine merge candidates are constructed based on the motion information using the following combinations of control point MVs in order: {CPMV1,CPMV2,CPMV3}, {CPMV1,CPMV2,CPMV4}, {CPMV1,CPMV3,CPMV4}, {CPMV2,CPMV3,CPMV4}, {CPMV1,CPMV2}, {CPMV1,CPMV3}.

[0116] A combination of three CPMVs constructs a six-parameter affine merge candidate, and a combination of two CPMVs constructs a four-parameter affine merge candidate. To avoid motion scaling processing, if the reference indexes of the control points are different, the associated combination of control point MVs is discarded.

[0117] After the inheritance and construction affine merge candidates have been checked, a zero MV is inserted at the end of the merge candidate list if the list is not already full.

[0118] In some embodiments, for CUs with both width and height equal to or greater than 16, the affine AMVP mode may be applied. A CU-level affine flag is signaled in the bitstream to indicate whether the affine AMVP mode is used, and another flag is signaled to indicate whether 4-parameter affine or 6-parameter affine is used. The difference between the CPMV of the current CU and their predictors is signaled in the bitstream. The affine AVMP candidate list size is 2 and may be generated using the following four types of CPVM candidates in order: (i) inherited affine AMVP candidates extrapolated from the CPMVs of neighboring CUs; (ii) Construct affine AMVP candidates derived using translational MVs of neighboring CUs; (iii) translational MVs from adjacent CUs; ​​and (iv) Zero MV.

[0119] The check order of the inherited affine AMVP candidates is similar to that of the inherited affine merge candidates in one example. The difference is that for the AVMP candidates, the affine CUs that have the same reference picture as the current block are considered. No pruning process is applied when inserting the inherited affine motion predictor into the candidate list.

[0120] The constructed AMVP candidate is derived from the specified spatial neighborhood shown in Figure 16. The same check order as done in affine merge candidate construction is used. In addition, the reference picture indexes of the neighboring blocks are also checked. The first block in the check order that is inter-coded and has the same reference picture as the current CU is used. When the current CU is coded with a four-parameter affine model and CPMV0 and CPMV1 are both available, the available CPMV is added as one candidate in the affine AMVP list. When the current CU is coded with a six-parameter affine mode and all three CPMVs (CPMV0, CPMV1, and CPMV2) are available, the available CPMV is added as one candidate in the affine AMVP list. Otherwise, the constructed AMVP candidate is set as unavailable.

[0121] If the affine AMVP list candidates are still less than 2 after the inherited affine AMVP candidates and constructed AMVP candidates are checked, the translational motion vectors adjacent to the control points, if available, are added to predict all control point MVs for the current CU. Finally, if the affine AMVP list is not yet filled, zero MVs are used to fill the affine AMVP list.

[0122] In one embodiment, an affine merge with motion vector difference (affine MMVD) mode can be used. An available affine merge candidate can be selected from a sub-block based merge list as a base predictor. A motion vector offset for each control point's motion vector value from the base predictor can be applied. If no affine merge candidate is available, affine MMVD is not used. If affine MMVD is used, a distance index and an offset direction index can be signaled later.

[0123] A distance index (IDX) may be signaled to indicate which distance offset to use from an offset table such as the one shown in Table 1.

[0124] [Table 1]

[0125] The distance index represents four directions, as shown in Table 2, and only the x or y direction can have MV differences, not both directions.

[0126] [Table 2]

[0127] If the inter prediction is uni-predictive, the signaled distance offset may be applied to the offset direction for each control point predictor. The result may be the MV value of each control point.

[0128] If the inter prediction is bi-predictive, the signaled distance offset may be applied relative to the signaled offset direction for the L0 motion vector of the control point predictor, and the offset applied to the L1 MV may be applied based on mirroring or scaling, as specified below.

[0129] If the inter prediction is bi-predictive, the signaled distance offset is applied relative to the signaled offset direction for the L0 motion vector of the control point predictor. In L1 CPMV, the offset can be applied based on mirroring, where the same amount of distance offset is applied in the opposite direction.

[0130] In one embodiment, a POC distance-based offset mirroring method may be used for bi-prediction. When the base candidate is bi-predicted, the L0 applied offset is signaled, and the offset on L1 may depend on the temporal positions of the reference pictures on list 0 and list 1. If both reference pictures are on the same temporal side of the current picture, the same distance offset and the same offset direction may be applied to the CPMV of L0 and L1. When the two reference pictures are on different sides of the current picture, the CPMV of L1 may have a distance offset applied in the opposite offset direction.

[0131] In one embodiment, a POC distance-based offset scaling method is used for bi-prediction. When the base candidate is bi-predicted, the offset applied to L0 is as signaled, and the offset applied to L1 may be scaled based on the temporal distance of the reference pictures on list 0 and list 1.

[0132] In one embodiment, the distance offset value range is expanded into three offset tables, such as the three different entries shown in Table 3. Each offset table (e.g., each row of Table 3) is adaptively selected based on the picture resolution. In one example, the offset tables are selected based on the picture resolution. With reference to FIG. 3, the first offset table (e.g., "Distance Offset 1") is selected when the picture height is equal to or greater than 1080. The second offset table (e.g., "Distance Offset 2") is selected when the picture height is less than 1080 and equal to or greater than 720. The third offset table (e.g., "Distance Offset 3") is selected when the picture height is less than 720.

[0133] [Table 3]

[0134] Local illumination compensation (LIC) is a prediction technique, such as an inter-prediction technique, for modeling local illumination variations between a current block and a predictor (also called a predictor block) of the current block using a linear function. LIC may be applied to, but is not limited to, uni-prediction modes. The predictor may be determined based on a reference block of the current block. The reference block is in a reference picture. In one example, such as a uni-prediction mode, the MV of the current block points from the current block to the reference block, and the predictor is the reference block of the current block. In one example, the value p of a sample (e.g., a reference sample) in the predictor (e.g., reference block) is i [x,y] is the updated value p of the sample in the updated predictor as shown in Equation 3. f It is modified using a function to determine [x,y]. p f [x,y]=α×p i [x,y]+β Equation 3

[0135] The parameters of the linear function can be denoted by a scaling factor (also called scale) α and an offset β to compensate for illumination changes. i [x,y] may be a reference sample at position [x,y] on the reference picture, and the reference sample may be pointed to by the MV of the current block. The scaling factor α and offset β may be derived based on a current template of the current block (also referred to as a current block template) and a reference template of the reference block (also referred to as a reference block template) using any suitable method, such as a least squares method. In various embodiments, the scaling factor α and offset β are not signaled, and no signaling overhead is required for the scaling factor α and offset β. In one example, a LIC flag is signaled to indicate the use of LIC. LIC may be used in any suitable standard, such as within and beyond VVC.

[0136] The current block may be coded based on the updated predictor in merge mode, skip mode, etc. The current block may be coded based on the updated predictor and additional information, such as residual data, in AMVP mode.

[0137] In the related art, the LIC only uses a flag (e.g., a LIC flag) to indicate whether the LIC is enabled or not, and does not have parameter adjustments to improve the accuracy of illumination compensation when the LIC is enabled.

[0138] According to one aspect of the present disclosure, one or more parameters of a parameter set of the LIC (e.g., including a scaling factor α and an offset β) may be adjusted. The one or more parameters may be adjusted using a single index or multiple indexes. In one example, the scaling factor α and / or the offset β are adjusted using one or more indexes.

[0139] 17 illustrates an example LIC with parameter adjustment. A current block (1701) in a current picture has a current template (also called a neighboring reconstructed template) (1721). The current template (1721) may have any suitable shape and any suitable size. The current template (1721) may include samples (e.g., reconstructed samples) of the neighboring reconstructed block(s) of the current block (1701).

[0140] In the example shown in FIG. 17, the current template (1721) of the current block (1701) includes a top template (1722) and a left template (1723). Each of the top template (1722) and the left template (1723) may have any suitable shape and any suitable size. The top template (1722) may include samples in one or more top neighboring blocks of the current block (1701). In one example, the top template (1722) may include four rows of samples in one or more top neighboring blocks of the current block (1701). The left template (1723) may include samples in one or more left neighboring blocks of the current block (1701). In one example, the left template (1723) may include four columns of samples in one or more left neighboring blocks of the current block (1701).

[0141] In one example, the current template of the current block (1701) includes only the top template (1722) or only the left template (1723). In one example, the current template of the current block (1701) includes the top template (1722), the left template (1723), and the top-left template (1731).

[0142] The MV (1702) of the current block (1701) may point to a reference block (1703) in a reference picture. The reference block (1703) may have a reference template, such as a reference template (1725), that corresponds to the current template (1721).

[0143] The reference template (1725) may have the same shape and size as the current template. In the example of FIG. 17, the reference template (1725) of the reference block (1703) includes a top template (1726) and a left template (1727). The top template (1726) corresponding to the top template (1722) may include samples in one or more top neighboring blocks of the reference block (1703). The left template (1727) corresponding to the left template (1723) may include samples in one or more left neighboring blocks of the reference block (1703).

[0144] A predictor of the current block (1701) may be determined based on a reference block (1703). In one example, such as a uni-prediction mode, the predictor is the reference block (1703), e.g., sample values ​​of the predictor are equal to respective sample values ​​of the reference block (1703).

[0145] The sample values ​​of the predictor of the current block (1701) may be modified using LIC to compensate for local illumination variations. According to one embodiment of the present disclosure, the updated values ​​p f [x,y] is the value of the sample p in the predictor as shown in Eq. i It can be based on a linear function of [x,y]. p f [x,y]=(α+μ 1 )×p i [x,y]+(β+μ 2 ×T avg ) Equation 4

[0146] Equation 4 can be written as Equation 5 below: p f [x,y]=α f ×p i [x,y]+β f formula 5

[0147] In Equation 5, the final scaling factor α f is the scaling coefficient α and the first parameter μ1 and the final offset β f is the offset β and the second parameter μ 2 In one example, the final offset β f is (β+μ 2 ×T avg ) Equation 5 shows that the updated predictor is f , the final offset β f , and a predictor (e.g., a reference block (1703)).

[0148] The parameter adjustment is the first parameter μ 1 and the second parameter μ 2 does not apply to LIC when is equal to zero.

[0149] As described above, the scaling factor α and offset β may be determined based on a current template (e.g., current template (1721)) of the current block (1701) and a reference template (e.g., reference template (1725)) of the reference block (1703) using any suitable method, such as the least squares method.

[0150] Parameter T avg may be determined from a reference template (e.g., reference template (1725)) and / or a current template (e.g., current template (1721)) of the current block (1701). In one example, the parameter T avg is the mean value of the reference template (e.g., reference template (1725)). For example, the parameter T avg is the average value of the sample values ​​of the entire or a subset of the reference template (e.g., the reference template (1725)). avg is the average value of the current template (e.g., current template (1721)). For example, the parameter T avg is the average value of the samples in the entire or a subset of the current template.

[0151] In one example, the parameter T avg The reference template used to determine α differs from the reference template used to determine the scaling factor α and the offset β. avg The current template used to determine {overscore (α)} differs from the current template used to determine the scaling factor α and the offset β.

[0152] In one example, the parameter T avg is 1, so the final offset β f is (β+μ 2 ) Therefore, the update value p f [x,y] is (α+μ 1 )×p i [x,y]+(β+μ 2 ).

[0153] The first parameter μ 1 and / or the second parameter μ 2 may be signaled, e.g., indicated, by LIC information of one or more blocks, including the current block (1701). In one embodiment, the LIC information of one or more blocks is signaled in the video bitstream.

[0154] The first parameter μ 1 and / or the second parameter μ 2 may be signaled within a limited range of values, such as from −5 to +5. In one example, the first parameter μ 1 is signaled within a limited range of positive values ​​or a limited range of negative values. 2 is signaled within a limited range of positive values ​​or a limited range of negative values.

[0155] In one embodiment, the LIC information of one or more blocks is a first parameter μ 1 and the second parameter μ 2 and the first parameter μ 1and the second parameter μ 2 The other is the first parameter μ 1 and the second parameter μ 2 The determination may be based on one of the above.

[0156] In one example, μ 2 =-μ 1 The LIC information of one or more blocks is a first parameter μ 1 and the second parameter μ 2 is the first parameter μ 1 From -μ 1 In one example, the LIC information of one or more blocks is determined as a second parameter μ 2 and the first parameter μ 1 is the second parameter μ 2 From -μ 2 is determined as:

[0157] The first parameter μ 1 and the second parameter μ 2 The relationship between (e.g., μ 2 =-μ 1 ) is known, for example, to the decoder, the first parameter μ 1 and the second parameter μ 2 For example, the first parameter μ 1 μ, which is LIC information that shows only 2 =-μ 1 is signaled in the bitstream. In one example, the first parameter μ 1 Only the 100% ...

[0158] In one embodiment, (i) a first parameter μ 1 and (ii) a second parameter μ 2 is equal to zero, (i) the first parameter μ 1 and (ii) a second parameter μ 2 In one embodiment, the LIC information of one or more blocks includes (i) a first parameter μ1 and (ii) a second parameter μ 2 For example, the first parameter μ 1 is equal to zero, and the LIC information of one or more blocks is the first parameter μ 1 In one example, the first parameter μ 1 is equal to zero and is not signaled in the bitstream. 2 is equal to zero and is not signaled in the bitstream.

[0159] The LIC information of one or more blocks includes (i) a first parameter μ 1 and / or the second parameter μ 2 or (ii) the first parameter μ 1 and / or the second parameter μ 2 The index may include one or more indices indicating

[0160] The first parameter μ 1 The second parameter μ may be a floating point value and may be quantized with the first plurality of bits. The LIC information of one or more blocks may include the first plurality of bits. 2 may be a floating point value and may be quantized with the second plurality of bits. The LIC information of one or more blocks may include the second plurality of bits.

[0161] The LIC information of one or more blocks is represented by a first parameter μ 1 or the second parameter μ 2 The first parameter μ may include at least one index indicating at least one of 1 and / or the second parameter μ 2 may be signaled by one or more indexes that point to the lookup table(s).

[0162] In one example, the lookup table may store a parameter pair corresponding to the index (e.g., a first parameter μ 1 and the second parameter μ2 ) and the LIC information is the first parameter μ 1 and the second parameter μ 2 Contains a single index that indicates

[0163] In one example, the first lookup table includes a first index and a first parameter μ 1 and the second lookup table indicates a first relationship between a second index and a second parameter μ 2 Therefore, the LIC information is based on the first parameter μ 1 The first index indicates the 2 and a second index indicating the first parameter μ 1 or the second parameter μ 2 is zero, the first non-zero parameter μ 1 or the second parameter μ 2 A single index is used to denote the first parameter μ 1 and the second parameter μ 2 The relationship between (e.g., μ 2 =-μ 1 ) is known, the first parameter μ 1 or the second parameter μ 2 A single index may be used to indicate

[0164] The LIC information for one or more blocks may be signaled at any appropriate level, such as at the coding unit (CU) level or at a higher level than the CU level (e.g., the CTU level, the slice level, etc.).

[0165] In one example, the LIC information of one or more blocks is signaled at the CU level, and the one or more blocks are in the same CU, and the first parameter μ 1 and the second parameter μ 2 is applicable to the CU. Different CUs may have different first parameters and / or different second parameters. For example, the first parameter μ1 and the second parameter μ 2 are the first parameters μ of the second CU, respectively. 1 and the second parameter μ 2 It is different from.

[0166] In one example, the LIC information of the one or more blocks is signaled at a high level, such as a slice level. The one or more blocks include blocks in multiple CUs in a slice. The first parameter μ 1 and the second parameter μ 2 is applicable to multiple CUs in a slice. Multiple CUs in a slice may share the same first parameter μ 1 Multiple CUs in a slice may have the same second parameter μ 2 may have the following structure:

[0167] In one example, the first parameter μ 1 and / or the second parameter μ 2 One or more indices indicating the CU level, CTU level, or slice level may be signaled at different levels.

[0168] The above embodiment may be appropriately adapted when LIC is operated at a sub-block level in a CU, for example, when LIC is performed at a sub-block level in a current block. The current block may include multiple sub-blocks. Each sub-block may include one or more samples in the current block. For example, each of the multiple sub-blocks is associated with a respective sub-block MV. The MVs associated with each of the multiple sub-blocks may be different. Each of the MVs may point to a respective reference sub-block in a reference picture. The multiple sub-blocks may be respectively predicted based on the multiple reference sub-blocks associated with the respective MVs. In one example, the multiple sub-blocks are predicted using an affine merge mode, an affine AMVP mode, an affine MMVD mode, etc.

[0169] The plurality of sub-blocks may include a first sub-block and a second sub-block. 1 and / or the second parameter μ 2 The LIC information of one or more blocks indicating may be applied to one or more of the sub-blocks of the current block. 1 and the second parameter μ 2 can be applied to multiple sub-blocks. For example, the first sub-block and the second sub-block have the same first parameter μ 1 and the first sub-block and the second sub-block have the same second parameter μ 2 has.

[0170] In one embodiment, each sub-block has a respective derived parameter set used in the LIC.

[0171] For the first sub-block in the current block, Equation 4 may be adapted to Equation 6. The update value p f1 [x 1 ,y 1 ] is a linear function of the value of the first sample p i1 [x 1 ,y 1 ] could be the case. p f1 [x 1 ,y 1 ]=(α i1 +μ 1 )×p i1 [x 1 ,y 1 ]+(β i1 +μ 2 ×T avg,1 ) Equation 6

[0172] The first MV of the first sub-block points to the first reference sub-block. i1 and the first initial offset β i1is associated with the first sub-block to compensate for local illumination changes for the first sub-block. avg,1 may be associated with the first sub-block to compensate for local illumination changes for the first sub-block. i1 and the first initial offset β i1 may be determined based on a first portion of the current template and a first portion of the reference template. For example, the first portion of the current template includes samples of a reconstructed spatially adjacent block(s) of the first sub-block. The first portion of the reference template includes samples of a reconstructed spatially adjacent block(s) of the first reference sub-block. The parameter T avg,1 may be determined based on a first portion of the current template and / or a first portion of the reference template.

[0173] For a second sub-block in the current block, Equation 4 may be adapted to Equation 7. The update value p f2 [x 2 ,y 2 ] is a linear function of the value of the second sample p i2 [x 2 ,y 2 ] could be the case. p f2 [x 2 ,y 2 ]=(α i2 +μ 1 )×p i2 [x 2 ,y 2 ]+(β i2 +μ 2 ×T avg,2 ) Equation 7

[0174] The second MV of the second sub-block points to the second reference sub-block. i2 and the second initial offset β i2is associated with the second sub-block to compensate for local illumination changes for the second sub-block. avg,2 A second initial scaling factor α can be associated with the second sub-block to compensate for local illumination changes for the second sub-block. i2 and the second initial offset β i2 may be determined based on the second portion of the current template and the second portion of the reference template. For example, the second portion of the current template includes samples of the reconstructed spatially adjacent block(s) of the second sub-block. The second portion of the reference template includes samples of the reconstructed spatially adjacent block(s) of the second reference sub-block. The parameter T avg,2 may be determined based on a second portion of the current template and / or a second portion of the reference template.

[0175] In one embodiment, multiple sub-blocks may use the same set of derived parameters (e.g., the first initial scaling factor α i1 , the first initial offset β i1 , and / or the parameter T avg,1 For example, the first initial scaling factor α i1 is the second initial scaling factor α i2 and the first initial offset β i1 is the second initial offset β i2 In one example, the parameter T avg,1 is the parameter T avg,2The shared parameter set of the multiple sub-blocks may be determined based on the current template and the reference template. In one example, the reference template may be determined based on a boundary sub-block of the current block that is a neighborhood of another block(s) outside the current block. For example, the MV associated with the boundary sub-block may point to multiple sub-blocks in the reference block, and the reference template includes samples of the reconstructed spatially adjacent block(s) of the multiple sub-blocks in the reference block. In one example, the reference template includes a first portion of the reference template that may be determined based on the first MV and a second portion of the reference template that may be determined based on the second MV.

[0176] FIG. 18 shows a flow chart outlining an encoding process (1800) according to one embodiment of the present disclosure. In various embodiments, the process (1800) is performed by processing circuitry, such as processing circuitry in terminal devices (310), (320), (330), and (340), processing circuitry performing the functions of a video encoder (e.g., (403), (603), (703)). In some embodiments, the process (1800) is implemented with software instructions, and thus the processing circuitry performs the process (1800) when the processing circuitry executes the software instructions. The process begins at (S1801) and proceeds to (S1810).

[0177] In (S1810), the initial scaling coefficient α of the first sub-block in the current block i1 , the initial offset β of the first sub-block i1 , as well as the first parameter μ of one or more blocks 1 and the second parameter μ 2 At least one of the following may be determined. The one or more blocks may include a current block that is coded with LIC. The first MV of the first sub-block points to a first reference block of reference blocks in the reference picture. The reference block corresponds to the current block.

[0178] Initial scaling factor α of the first subblock in the current block i1 and the initial offset β of the first subblock in the current block i1 may be determined based on a first portion of a current template for the current block and a first portion of a reference template for the reference block.

[0179] In one example, the initial scaling factor α of the first sub-block in the current block is i1 and the initial offset β of the first subblock in the current block i1 may be determined based on a current template of the current block and a reference template of the reference block.

[0180] The first parameter μ of one or more blocks 1 and / or a second parameter μ of one or more blocks 2 may be determined based on one or more blocks.

[0181] In one example, a higher level (e.g., a CTU or slice) higher than a CU includes a first block(s) coded with LIC and a second block(s) not coded with LIC. The first block(s) may have the same first parameter μ determined based on, for example, one or more of the first block(s). 1 and the same second parameter μ 2 Alternatively, the first block(s) may have different first parameters μ 1 and a different second parameter μ 2 may have the following structure:

[0182] In (S1820), in one example, the final scaling coefficient α f1 is the first parameter μ 1 and the initial scaling factor α i1For example, the final scaling factor α of the first sub-block in the current block is determined based on f1 is the first parameter μ of one or more blocks 1 and the initial scaling coefficient α of the first sub-block in the current block i1 It is determined to be the sum of

[0183] In one example, the final offset β of the first sub-block f1 is the second parameter μ 2 and the initial offset β i1 For example, the parameter T of the first subblock in the current block is avg,1 is determined based on at least one of the first portion of the current template or the first portion of the reference template. f1 is (β i1 +μ 2 ×T avg,1 ) is determined.

[0184] In one example, the parameter T avg,1 may be determined based on a current template of the current block and a reference template of the reference block.

[0185] In (S1830), an updated first predictor sub-block (e.g., an updated first reference sub-block) in a predictor (e.g., a reference block) corresponding to the current block is updated by a final scaling coefficient α f1 , the final offset β f1 , and a first predictor sub-block (e.g., a first reference sub-block) in the predictor.

[0186] At (S1840), a first sub-block in the current block may be coded based on the updated first predictor sub-block. 1 and / or the second parameter μ 2One or more blocks of LIC information may be encoded indicating:

[0187] The coded LIC information of one or more blocks may be signaled in a video bitstream. The LIC information of one or more blocks may be signaled at a coding unit (CU) level or at a level higher than the CU level.

[0188] In one example, (i) a first parameter μ 1 and (ii) a second parameter μ 2 one of the first parameters μ 1 and (ii) a second parameter μ 2 It does not indicate one side.

[0189] In one example, the LIC information of one or more blocks includes a first parameter μ 1 or the second parameter μ 2 The at least one index indicating at least one of

[0190] In one example, the first parameter μ 1 or the second parameter μ 2 At least one of the blocks is a floating point value and is quantized with multiple bits, and the LIC information of one or more blocks includes multiple bits.

[0191] The process (1800) then proceeds to (S1899) and ends.

[0192] Process (1800) can be adapted to various scenarios as appropriate, and steps within process (1800) can be adjusted accordingly. One or more of the steps within process (1800) can be adapted, omitted, repeated, and / or combined. Any suitable order can be used to perform process (1800). Additional step(s) can be added.

[0193] In one example, the LIC information of one or more blocks includes (i) a first parameter μ 1 and (ii) a second parameter μ 2 (i) the first parameter μ 1 and (ii) a second parameter μ 2 The other is (i) the first parameter μ 1 and (ii) a second parameter μ 2 The determination is based on one of the following:

[0194] In one example, the first sub-block in the current block is the current block, the first predictor sub-block in the predictor is the predictor (e.g., the reference block), the first portion of the current template is the current template, and the first portion of the reference template is the reference template. In one example, the updated predictor is determined using Equation 4 or Equation 5.

[0195] In one embodiment, the current block includes a first sub-block and a second sub-block, and a first parameter μ indicated in the LIC information of one or more blocks. 1 or the second parameter μ 2 At least one of the following is applied to the first sub-block and the second sub-block: the second sub-block is an initial scaling factor α i1 Another initial scaling factor α, which may be the same or different from i2 and the initial offset β of the first sub-block i1 Another initial offset β, which may be the same or different from i2 An updated second predictor sub-block (e.g., an updated second reference sub-block) in the predictor corresponding to the second sub-block may be determined using Equation 7. The second sub-block may be encoded based on the updated second predictor sub-block.

[0196] FIG. 19 shows a flow chart outlining a decoding process (1900) according to one embodiment of the present disclosure. In various embodiments, the process (1900) is performed by processing circuitry, such as processing circuitry in terminal devices (310), (320), (330), and (340), processing circuitry performing the functions of a video encoder (403), processing circuitry performing the functions of a video decoder (410), processing circuitry performing the functions of a video decoder (510), processing circuitry performing the functions of a video encoder (603), etc. In some embodiments, the process (1900) is implemented with software instructions, and thus the processing circuitry performs the process (1900) as the processing circuitry executes the software instructions. The process starts at (S1901) and proceeds to (S1910).

[0197] At (S1910), prediction information for one or more blocks may be decoded from the coded video bitstream. The prediction information may indicate that local illumination compensation (LIC) is applied to one or more blocks and may include LIC information for one or more blocks, including the current block to be reconstructed.

[0198] In one example, LIC information for one or more blocks is signaled at a coding unit (CU) level.

[0199] In one example, LIC information for one or more blocks is signaled at a level higher than the CU level.

[0200] In (S1920), the final scaling coefficient α of the first sub-block in the current block f1 and the final offset β of the first subblock in the current block f1 can be determined based on the LIC information.

[0201] In one embodiment, the initial scaling factor α of the first sub-block in the current block is i1 and the initial offset β of the first subblock in the current block i1is determined based on a first portion of a current template for the current block and a first portion of a reference template for the reference block.

[0202] In one example, the initial scaling factor α of the first sub-block in the current block is i1 and the initial offset β of the first subblock in the current block i1 may be determined based on a current template of the current block and a reference template of the reference block.

[0203] The LIC information of the one or more blocks may be signaled in a coded video bitstream, and a first parameter μ 1 and a second parameter μ of one or more blocks 2 The final scaling factor α of the first sub-block in the current block can be represented as f1 is the first parameter μ of one or more blocks 1 and the initial scaling coefficient α of the first sub-block in the current block i1 The final offset β of the first sub-block in the current block can be determined based on f1 is the second parameter μ of one or more blocks 2 and the initial offset β of the first subblock in the current block i1 It can be determined based on:

[0204] In one example, the final scaling factor α of the first sub-block in the current block is f1 is the first parameter μ of one or more blocks 1 and the initial scaling coefficient α of the first sub-block in the current block i1 It is determined to be the sum of

[0205] In one example, the parameter T of the first subblock in the current block avg,1is determined based on at least one of the first portion of the current template or the first portion of the reference template, and a final offset β of the first sub-block in the current block f1 is (β i1 +μ 2 ×T avg,1 ) is determined.

[0206] In one example, the parameter T avg,1 may be determined based on a current template of the current block and a reference template of the reference block.

[0207] In one example, the LIC information of one or more blocks includes (i) a first parameter μ 1 and (ii) a second parameter μ 2 (i) the first parameter μ 1 and (ii) a second parameter μ 2 The other is (i) the first parameter μ 1 and (ii) a second parameter μ 2 The determination is based on one of the following:

[0208] In one example, (i) a first parameter μ 1 and (ii) a second parameter μ 2 one of the first parameters μ 1 and (ii) a second parameter μ 2 It does not indicate one side.

[0209] In one example, the LIC information of one or more blocks includes a first parameter μ 1 or the second parameter μ 2 The at least one index indicating at least one of

[0210] In one example, the first parameter μ 1 or the second parameter μ 2 At least one of the blocks is a floating point value and is quantized with multiple bits, and the LIC information of one or more blocks includes multiple bits.

[0211] In (S1930), the updated first predictor sub-block in the predictor corresponding to the current block is updated by the final scaling coefficient α f1 , the final offset β f1 , and the first predictor sub-block. As described above, the predictor may be determined based on a reference block. In one example, the predictor is a reference block, e.g., the sample values ​​of the predictor are equal to the respective sample values ​​of the reference block. The update value of the first sample in the first predictor sub-block in the predictor is α f1 ×p i1 +β f1 It may be equal to p i1 may be the value of the first sample in the first predictor sub-block in the predictor.

[0212] At (S1940), a first sub-block in the current block may be reconstructed based on an updated first predictor sub-block in the predictor.

[0213] In one example, a sample value of a first sub-block in a current block is equal to a corresponding sample value in an updated first predictor sub-block in the predictor.

[0214] In one example, a first sub-block in a current block is reconstructed based on an updated first predictor sub-block in the predictor and additional information (eg, residual data).

[0215] The process (1900) can be adapted to various scenarios as appropriate, and the steps within the process (1900) can be adjusted accordingly. One or more of the steps within the process (1900) can be adapted, omitted, repeated, and / or combined. Any suitable order can be used to perform the process (1900). Additional step(s) can be added.

[0216] In one embodiment, the first sub-block in the current block is the current block, the first predictor sub-block in the predictor is the predictor (e.g., a reference block of the current block), the first portion of the current template is the current template, and the first portion of the reference template is a reference template of the reference block. In one example, the updated predictor is determined using Equation 4 or Equation 5.

[0217] In one embodiment, the current block includes a first sub-block and a second sub-block, and a first parameter μ indicated in the LIC information of one or more blocks. 1 or the second parameter μ 2 At least one of the following is applied to the first sub-block and the second sub-block: the second sub-block is an initial scaling factor α i1 Another initial scaling factor α, which may be the same or different from i2 and the initial offset β of the first sub-block i1 Another initial offset β, which may be the same or different from i2 An updated second predictor sub-block in the predictor corresponding to the second sub-block may be determined using Equation 7. The second sub-block may be encoded based on the updated second predictor sub-block.

[0218] The embodiments of the present disclosure may be used separately or combined in any order. Furthermore, each of the methods (or embodiments), the encoder, and the decoder may be implemented by a processing circuit (e.g., one or more processors or one or more integrated circuits). In one example, the one or more processors execute a program stored in a non-transitory computer-readable medium.

[0219] The techniques described above can be implemented as computer software using computer-readable instructions physically stored on one or more computer-readable media. For example, Figure 20 illustrates a computer system (2000) suitable for implementing certain embodiments of the disclosed subject matter.

[0220] Computer software can be coded using any suitable machine code or computer language that can be assembled, compiled, linked, or similar mechanisms to create code containing instructions that can be executed directly, or via interpretation, microcode execution, etc., by one or more computer central processing units (CPUs) and graphics processing units (GPUs), etc.

[0221] The instructions may be executed on various types of computers or computer components including, for example, personal computers, tablet computers, servers, smartphones, gaming consoles, Internet of Things devices, and the like.

[0222] The components illustrated in Figure 20 for the computer system (2000) are exemplary in nature and are not intended to suggest any limitation as to the scope of use or functionality of the computer software implementing the embodiments of the present disclosure. The arrangement of components should not be interpreted as having a dependency or requirement regarding any one or combination of components illustrated in the exemplary embodiment of the computer system (2000).

[0223] The computer system (2000) may include certain human interface input devices. Such human interface input devices may be responsive to input by one or more human users, for example, via tactile input (e.g., keystrokes, swipes, data glove movements), audio input (e.g., voice, clapping), visual input (e.g., gestures), olfactory input (not shown). Human interface devices may also be used to capture certain media not necessarily directly associated with conscious human input, such as audio (speech, music, ambient sounds, etc.), images (scanned images, photographic images obtained from still image cameras, etc.), and video (two-dimensional video, three-dimensional video including stereoscopic video, etc.).

[0224] The input human interface devices may include one or more (only one of each shown) of a keyboard (2001), a mouse (2002), a trackpad (2003), a touch screen (2010), a data glove (not shown), a joystick (2005), a microphone (2006), a scanner (2007), a camera (2008).

[0225] The computer system (2000) may also include certain human interface output devices. Such human interface output devices may stimulate one or more of the senses of a human user, for example, by haptic output, sound, light, and smell / taste. Such human interface output devices may include haptic output devices (e.g., haptic feedback via a touch screen (2010), data gloves (not shown), or joystick (2005), although there may also be haptic feedback devices that do not function as input devices), audio output devices (e.g., speakers (2009), headphones (not shown)), visual output devices (e.g., screens (2010), including CRT screens, LCD screens, plasma screens, OLED screens, each with or without touch screen input capability, each with or without haptic feedback capability, some of which may be capable of two-dimensional visual output, or four or more dimensions of output by means of stereoscopic image output, virtual reality glasses (not shown), holographic displays, and smoke tanks (not shown), etc.), and printers (not shown).

[0226] The computer system (2000) may also include human accessible storage devices and their associated media, such as optical media including CD / DVD ROM / RW (2020) with media (2021) such as CDs / DVDs, thumb drives (2022), removable hard drives or solid state drives (2023), legacy magnetic media such as tapes and floppy disks (not shown), dedicated ROM / ASIC / PLD based devices (not shown) such as security dongles, and the like.

[0227] Those skilled in the art should also understand that the term "computer-readable medium" as used in connection with the subject matter of this disclosure does not encompass transmission media, carrier waves, or other transitory signals.

[0228] The computer system (2000) may also include an interface (2054) to one or more communication networks (2055). The network may be, for example, wireless, wired, optical. The network may further be local, wide area, metropolitan, vehicular and industrial, real-time, delay tolerant, etc. Examples of networks include local area networks such as Ethernet, wireless LAN, cellular networks including GSM, 3G, 4G, 5G, LTE, etc., television wired or wireless wide area digital networks including cable television, satellite television, and terrestrial broadcast television, vehicular and industrial including CANBus, etc. Certain networks typically require an external network interface adapter attached to a particular general-purpose data port (e.g., a USB port of the computer system (2000)) or peripheral bus (2049), while other networks are typically integrated into the core of the computer system (2000) by attachment to a system bus as described below (e.g., an Ethernet interface to a PC computer system, or a cellular network interface to a smartphone computer system). Using any of these networks, the computer system (2000) can communicate with other entities. Such communications may be unidirectional, receive only (e.g., television broadcast), unidirectional transmit only (e.g., CANbus to a particular CANbus device), or bidirectional, for example, to other computer systems using local or wide area digital networks. Specific protocols and protocol stacks may be used in each of these networks and network interfaces, as described above.

[0229] The aforementioned human interface devices, human accessible storage devices, and network interfaces may be attached to the core (2040) of the computer system (2000).

[0230] The cores (2040) may include one or more central processing units (CPUs) (2041), graphics processing units (GPUs) (2042), dedicated programmable processing units in the form of field programmable gate areas (FPGAs) (2043), hardware accelerators for specific tasks (2044), graphics adapters (2050), and the like. These devices may be connected via a system bus (2048), along with read-only memory (ROM) (2045), random access memory (2046), internal mass storage (2047), such as an internal non-user accessible hard drive, SSD, and the like. In some computer systems, the system bus (2048) is accessible in the form of one or more physical plugs, allowing expansion with additional CPUs, GPUs, and the like. Peripheral devices may be attached directly to the core's system bus (2048) or through a peripheral bus (2049). In one example, a screen (2010) may be connected to the graphics adapter (2050). Peripheral bus architectures include PCI, USB, and the like.

[0231] The CPU (2041), GPU (2042), FPGA (2043), and accelerator (2044) can execute certain instructions that can be combined to constitute the aforementioned computer code. That computer code can be stored in ROM (2045) or RAM (2046). Persistent data can be stored, for example, in internal mass storage (2047), while transitory data can also be stored in RAM (2046). Rapid storage and retrieval in any of the memory devices can be made possible by the use of cache memory, which can be closely associated with one or more of the CPU (2041), GPU (2042), mass storage (2047), ROM (2045), RAM (2046), etc.

[0232] The computer-readable medium can bear computer code for performing various computer-implemented operations. The medium and computer code may be those specially designed and constructed for the purposes of the present disclosure, or they may be of the available kind well known to those skilled in the computer software arts.

[0233] By way of example and not limitation, a computer system (2000) having an architecture, and in particular a core (2040), may provide functionality as a result of a processor (or processors) (including CPUs, GPUs, FPGAs, accelerators, etc.) executing software embodied in one or more tangible computer-readable media. Such computer-readable media may be user-accessible mass storage as described above, as well as media associated with specific storage of the core (2040) that is non-transitory in nature, such as the core internal mass storage (2047) or ROM (2045). Software implementing various embodiments of the present disclosure may be stored in such devices and executed by the core (2040). The computer-readable media may include one or more memory devices or chips, depending on the particular needs. The software may cause the core (2040), and in particular the processors (including CPUs, GPUs, FPGAs, etc.) therein, to perform certain processes or certain portions of certain processes described herein, including defining data structures stored in RAM (2046) and modifying such data structures according to processes defined by the software. Additionally or alternatively, the computer system may provide functionality as a result of logic hardwired or otherwise embodied in circuitry (e.g., accelerator (2044)), which may operate in place of or in conjunction with software to perform particular processes or particular portions of particular processes described herein. References to software may encompass logic, and vice versa, where appropriate. References to computer-readable media may encompass circuitry (such as integrated circuits (ICs)) that stores software for execution, circuitry that embodies logic for execution, or both, where appropriate. The present disclosure encompasses any suitable combination of hardware and software.

[0234] Appendix A: Acronyms JEM: joint exploration model VVC: versatile video coding BMS:benchmark set MV: Motion Vector HEVC: High Efficiency Video Coding SEI: Supplementary Enhancement Information VUI: Video Usability Information GOP: Groups of Pictures TU: Transform Units PU: Prediction Units CTU: Coding Tree Units CTB: Coding Tree Blocks PB: Prediction Blocks HRD: Hypothetical Reference Decoder SNR: Signal Noise Ratio CPU: Central Processing Units GPU: Graphics Processing Units CRT:Cathode Ray Tube LCD: Liquid-Crystal Display OLED: Organic Light-Emitting Diode CD: Compact Disc DVD: Digital Video Disc ROM: Read-Only Memory RAM: Random Access Memory ASIC: Application-Specific Integrated Circuit PLD: Programmable Logic Device LAN: Local Area Network GSM: Global System for Mobile communications LTE: Long-Term Evolution CANBus: Controller Area Network Bus USB: Universal Serial Bus PCI: Peripheral Component Interconnect FPGA: Field Programmable Gate Areas SSD: solid-state drive IC: Integrated Circuit CU: Coding Unit RD: Rate-Distortion

[0235] While this disclosure describes several exemplary embodiments, there exist modifications, substitutions, and various alternative equivalents that are within the scope of this disclosure. It will thus be appreciated that those skilled in the art will be able to devise numerous systems and methods that, although not explicitly shown or described herein, embody the principles of this disclosure and are therefore within the spirit and scope of this disclosure. [Explanation of symbols]

[0236] 101 Samples 102,103 Arrow 104 Square Block 201 Current Block 202,203,204,205,206 Samples 300 Communication Systems 310,320,330,340 Terminal Devices 350 Communication Network 400 Communication Systems 401 Video Source 402 Video Picture Stream 403 Video Encoder 404 Encoded Video Data 405 Streaming Server 406 Client Subsystem 407 Input copy of encoded video data 408 Client Subsystem 409 Copying of encoded video data 410 Video Decoder 411 Video Picture Output Stream 412 Display 413 Capture Subsystem 420 Electronic Devices 430 Electronic Devices 501 Channel 510 Video Decoder 512 Rendering Device 515 Buffer Memory 520 Entropy Decoder / Parser 521 Symbols 530 Electronic Devices 531 Receiver 551 Scaler / Descaler Unit 552 Intra-picture prediction unit 553 Motion Compensation Prediction Unit 555 Aggregator 556 Loop Filter Unit 557 Reference Picture Memory 558 Current Picture Buffer 601 Video Sources 603 Video Encoder 620 Electronic Devices 630 Source Coder 632 Coding Engine 633 Local Video Decoder 634 Reference Picture Memory 635 Predictors 640 Transmitter 643 Video Sequences 645 Entropy Coder 650 Controller 660 Communication Channels 703 Video Encoder 721 General-purpose controller 722 Intra Encoder 723 Residual Calculator 724 Residual Encoder 725 Entropy Encoder 726 Switch 728 Residual Decoder 730 InterEncoder 810 Video Decoder 871 Entropy Decoder 872 Intra Decoder 873 Residual Decoder 874 Reconstruction Module 880 Interdecoder 901 Current Block 1101 Current Picture 1102 Current Reference Picture 1103 Collocated Picture 1104 Colocated Reference Picture 1111 Current CU 1112 Colocate CU 1121 Scaled MV 1401 Motion Vector 1402 Ruma Subblock 1410 Current Block 1510 Current CU 1520 Current CU 1701 Current Block 1703 Reference Block 1721 Current Template 1722 Top template 1723 Left Template 1725 Reference Template 1727 Left Template 1731 Top Left Template 1800 Encoding Process 1900 Decryption Process 2000 Computer Systems 2001 Keyboard 2002 Mouse 2003 Trackpad 2005 Joystick 2006 Microphone 2007 Scanner 2008 Camera 2009 Speaker 2010 Touchscreen 2020 CD / DVD ROM / RW 2021 CD / DVD and other media 2022 Thumb Drive 2023 Removable Hard Drive or Solid State Drive 2040 Core 2041 Central Processing Unit (CPU) 2042 Graphics Processing Unit (GPU) 2043 Field Programmable Gate Area (FPGA) 2044 Hardware Accelerator 2045 Read-Only Memory (ROM) 2046 Random Access Memory, RAM 2047 Internal Mass Storage 2048 System Bus 2049 Surrounding Bus 2050 Graphics Adapter 2054 Interface 2055 Communication Network

Claims

1. 1. A method for video decoding in a video decoder, comprising: decoding prediction information for one or more blocks from a coded video bitstream, the prediction information indicating that Local Illumination Compensation (LIC) is applied to the one or more blocks and including LIC information for the one or more blocks, the one or more blocks including a current block to be reconstructed; and determining a final scaling coefficient α of a first sub-block in the current block based on offset information of at least one of a first parameter μ 1 of the one or more blocks or a second parameter μ 2 of the one or more blocks indicated by the LIC information. f1 and the final offset β of the first sub-block within the current block. f1 determining a final scaling factor α f1 based on an initial scaling factor α i1 and the first parameter μ 1 and a final offset β f1 based on an initial offset β i1 and the second parameter μ 2 ; f1 , the final offset β f1 and determining an updated first predictor sub-block in the predictor corresponding to the current block based on a first predictor sub-block in the predictor, wherein an updated value of a first sample in the first predictor sub-block in the predictor is α f1 ×p i1 +β f1 is equal to p i1 is a value of the first sample in the first predictor sub-block in the predictor; and reconstructing the first sub-block in the current block based on the updated first predictor sub-block in the predictor.

2. The initial scaling factor α of the first sub-block in the current block i1 and the initial offset β of the first sub-block in the current block. i1 The method of claim 1 , wherein the predictor is determined based on a first portion of a current template for the current block and a first portion of a reference template for a reference block, the predictor being based on the reference block.

3. The offset information indicated by the LIC information of the one or more blocks is: (i) the first parameter μ 1 and (ii) the second parameter μ 2 (i) the first parameter μ 1 and (ii) the second parameter μ 2 The other of the two is (i) the first parameter μ 1 and (ii) the second parameter μ 2 The method of claim 2, wherein the determination is based on the one of:

4. (i) the first parameter μ 1 and (ii) the second parameter μ 2 one of the first parameters μ 1 and (ii) the second parameter μ 2 The method of claim 2, wherein the one of the above is not indicated.

5. The LIC information of the one or more blocks is the first parameter μ 1 or the second parameter μ 2 The method of claim 2 , further comprising at least one index indicating the at least one of:

6. The first parameter μ 1 or the second parameter μ 2 The method of claim 2 , wherein the at least one of is a floating point value and is quantized with multiple bits, and the LIC information of the one or more blocks comprises the multiple bits.

7. The step of determining the final scaling factor comprises determining the final scaling factor α of the first sub-block in the current block. f1 the first parameter μ 1 and the initial scaling coefficient α i1 The method of claim 2 , further comprising: determining the sum of

8. The step of determining the final offset comprises: determining a parameter T of the first sub-block in the current block based on at least one of the first portion of the current template or the first portion of the reference template. avg，1 determining the final offset β of the first sub-block within the current block; f1 (β i1 +μ 2 ×T avg，1 3. The method of claim 2, further comprising: determining the first eigenvalue to be 0.01;

9. The method of claim 1 , wherein the LIC information for the one or more blocks is signaled at a coding unit (CU) level.

10. The method of claim 1 , wherein the LIC information for the one or more blocks is signaled at a level higher than a coding unit (CU) level.

11. 3. The method of claim 2 , wherein the first sub-block comprises the current block; the first predictor sub-block comprises the predictor; the first portion of the current template comprises the current template; and the first portion of the reference template comprises the reference template.

12. The current block includes the first sub-block and the second sub-block, and the first parameter μ indicated in the LIC information of the one or more blocks is 1 or the second parameter μ 2 is applied to the first sub-block and the second sub-block, and the second sub-block is adapted to adjust the initial scaling factor α of the first sub-block. i1 Another initial scaling factor α i2 and the initial offset β of the first sub-block i1 Another initial offset β i2 The method of claim 2, wherein the

13. An apparatus for video decoding, comprising a processing circuit configured to perform the method according to any one of claims 1 to 12.

14. A computer program causing a computer to carry out the method according to any one of claims 1 to 12.

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