Method and device for video processing and medium

Abstract

Embodiments of the present disclosure provide a solution for video processing. A method for video processing is presented. The method comprises: deriving, for a conversion between a video unit of a video and a bitstream of the video, a prediction sample of the video unit; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; and performing a conversion based on the refined prediction sample points.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to video processing techniques, and more particularly, to intra block copy (IBC) with local illumination compensation (LIC). Background Art

[0002] Nowadays, digital video capabilities are being applied to all aspects of people's lives. For video encoding / decoding, various types of video compression technologies have been proposed, such as MPEG-2, MPEG-4, ITU-TH.263, ITU-TH.264 / MPEG-4 Part 10 Advanced Video Codec (AVC), ITU-TH.265 High Efficiency Video Codec (HEVC) standard, and Versatile Video Codec (VVC) standard. However, it is generally expected to further improve the encoding and decoding efficiency of video encoding and decoding technologies. Summary of the invention

[0003] Embodiments of the present disclosure provide a solution for video processing.

[0004] In a first aspect, a method for video processing is proposed. The method includes: for conversion between a video unit of a video and a bitstream of the video, deriving a prediction sample of the video unit; deriving a refined prediction sample of the video unit by applying a refinement process to the prediction sample; and performing conversion based on the refined prediction sample. In this way, the encoding and decoding efficiency of IBC can be improved.

[0005] In a second aspect, a device for video processing is provided. The device includes a processor and a non-volatile memory having instructions thereon. The instructions, when executed by the processor, cause the processor to perform the method according to the first aspect of the present disclosure.

[0006] In a third aspect, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores instructions for causing a processor to execute the method according to the first aspect of the present disclosure.

[0007] In a fourth aspect, another non-transitory computer-readable recording medium is provided. The non-transitory computer-readable recording medium stores a bitstream of a video generated by a method performed by an apparatus for video processing. The method includes: deriving prediction samples of a video unit of the video; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; and generating a bitstream based on the refined prediction samples.

[0008] In a fifth aspect, a method for storing a bitstream of a video is provided. The method includes: deriving prediction samples of a video unit of the video; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; generating a bitstream based on the refined prediction samples; and storing the bitstream in a non-transitory computer-readable recording medium.

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become more apparent through the following detailed description with reference to the accompanying drawings. In the exemplary embodiments of the present disclosure, the same reference numerals generally refer to the same components.

[0011] Figure 1 A block diagram illustrating an example video encoding and decoding system is shown according to some embodiments of the present disclosure;

[0012] Figure 2 A block diagram illustrating a first example video encoder is shown according to some embodiments of the present disclosure;

[0013] Figure 3 shows a block diagram illustrating an example video decoder according to some embodiments of the present disclosure;

[0014] Figure 4 An example of an encoder block diagram of VVC is shown;

[0015] Figure 5 Several intra prediction modes are shown;

[0016] Fig. 6A and Figure 6B Reference samples for wide-angle intra prediction are shown;

[0017] Figure 7 The problem of discontinuity is shown in the case of orientations exceeding 45°;

[0018] Figure 8 An example of motion vector scaling for temporal merge candidates is shown;

[0019] Fig.9A and Fig. 9B The MMVD search point is shown;

[0020] Fig.10 An example of local illumination compensation is shown;

[0021] Fig.11 No subsampling for short edges is shown;

[0022] Fig.12 shows the IBC reference area depending on the current CU position;

[0023] Fig.13 An example of symmetry in a picture of screen content is shown;

[0024] Fig.14A A diagram showing BV adjustment for horizontal flipping is shown;

[0025] Fig. 14B A diagram showing BV adjustment for vertical flipping is shown;

[0026] Fig.15 shows the intra-frame template matching search area used;

[0027] Fig.16 shows a template used to derive parameters of the LIC for IBC;

[0028] Fig.17 A flowchart showing a method for video processing according to an embodiment of the present disclosure is shown; and

[0029] Fig.18 A block diagram of a computing device is shown in which various embodiments of the present disclosure may be implemented.

[0030] Throughout the drawings, the same or similar reference numbers generally refer to the same or similar elements. DETAILED DESCRIPTION

[0031] The principle of the present disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are described only for the purpose of illustrating and helping those skilled in the art to understand and implement the present disclosure, without implying any limitation on the scope of the present disclosure. In addition to the methods described below, the disclosure described herein can also be implemented in various ways.

[0032] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0033] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an example embodiment, it is claimed that such feature, structure, or characteristic, whether or not explicitly described, is within the knowledge of those skilled in the art to affect correlation with other embodiments.

[0034] It should be understood that, although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0035] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an" and "the" are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "include", "comprises", "has", "has", "includes" and / or "comprising" are used herein to indicate the presence of the features, elements and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. Example Environment

[0036] Figure 1 1 is a block diagram illustrating an example video codec system 100 that may utilize the techniques of the present disclosure. As shown, the video codec system 100 may include a source device 110 and a destination device 120. The source device 110 may also be referred to as a video encoding device, and the destination device 120 may also be referred to as a video decoding device. In operation, the source device 110 may be configured to generate encoded video data, and the destination device 120 may be configured to decode the encoded video data generated by the source device 110. The source device 110 may include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0037] The video source 112 may include a source such as a video acquisition device. Examples of a video acquisition device include, but are not limited to, an interface for receiving video data from a video content provider, a computer graphics system for generating video data, and / or a combination thereof.

[0038] The video data may include one or more pictures. The video encoder 114 encodes the video data from the video source 112 to generate a bitstream. The bitstream may include a bit sequence that forms a coded representation of the video data. The bitstream may include coded pictures and associated data. The coded pictures are coded representations of pictures. The associated data may include sequence parameter sets, picture parameter sets, and other grammatical structures. The I / O interface 116 may include a modulator / demodulator and / or a transmitter. The coded video data may be directly transmitted to the destination device 120 via the network 130A via the I / O interface 116. The coded video data may also be stored on a storage medium / server 130B for access by the destination device 120.

[0039] The destination device 120 may include an I / O interface 126, a video decoder 124, and a display device 122. The I / O interface 126 may include a receiver and / or a modem. The I / O interface 126 may obtain encoded video data from the source device 110 or the storage medium / server 130B. The video decoder 124 may decode the encoded video data. The display device 122 may display the decoded video data to the user. The display device 122 may be integrated with the destination device 120, or may be outside the destination device 120, which is configured to be connected to an external display device interface.

[0040] The video encoder 114 and the video decoder 124 may operate according to a video compression standard, such as the High Efficiency Video Codec (HEVC) standard, the Versatile Video Codec (VVC) standard, and other existing and / or future standards.

[0041] Figure 2 is a block diagram showing an example of a video encoder 200 according to some embodiments of the present disclosure, which may be Figure 1 An example of a video encoder 114 in the system 100 is shown.

[0042] Video encoder 200 may be configured to implement any or all of the techniques of this disclosure. Figure 2 In the example of , video encoder 200 includes multiple functional components. The techniques described in this disclosure can be shared between the various components of video encoder 200. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0043] In some embodiments, the video encoder 200 may include a segmentation unit 201, a prediction unit 202, a residual generation unit 207, a transformation unit 208, a quantization unit 209, an inverse quantization unit 210, an inverse transformation unit 211, a reconstruction unit 212, a cache 213 and an entropy coding unit 214, and the prediction unit 202 may include a mode selection unit 203, a motion estimation unit 204, a motion compensation unit 205 and an intra-frame prediction unit 206.

[0044] In other examples, the video encoder 200 may include more, fewer, or different functional components. In one example, the prediction unit 202 may include an intra-block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode in which at least one reference picture is a picture in which the current video block is located.

[0045] Furthermore, although some components (such as the motion estimation unit 204 and the motion compensation unit 205) may be integrated, for the purpose of explanation, these components are described in detail below. Figure 2 are shown separately in the example.

[0046] The partitioning unit 201 may partition a picture into one or more video blocks. The video encoder 200 and the video decoder 300 may support various video block sizes.

[0047] The mode selection unit 203 may select one of a plurality of encoding modes (intra-frame encoding or inter-frame encoding), for example, based on the error result, and provide the generated intra-frame encoded block or inter-frame encoded block to the residual generation unit 207 to generate residual block data, and to the reconstruction unit 212 to reconstruct the encoded block for use as a reference picture. In some examples, the mode selection unit 203 may select an intra-frame inter-frame joint prediction (CIIP) mode, in which the prediction is based on an inter-frame prediction signal and an intra-frame prediction signal. In the case of inter-frame prediction, the mode selection unit 203 may also select a resolution for a motion vector (e.g., sub-pixel precision or integer pixel precision) for the block.

[0048] To perform inter-frame prediction on the current video block, the motion estimation unit 204 may generate motion information for the current video block by comparing the current video block with one or more reference frames from the cache 213. The motion compensation unit 205 may determine a predicted video block for the current video block based on the motion information and decoded samples of pictures from the cache 213 other than the picture associated with the current video block.

[0049] The motion estimation unit 204 and the motion compensation unit 205 may perform different operations on the current video block, for example, depending on whether the current video block is in an I slice, a P slice, or a B slice. As used herein, an "I slice" may refer to a portion of a picture consisting of macroblocks, all of which are based on macroblocks within the same picture. Furthermore, as used herein, in some aspects, a "P slice" and a "B slice" may refer to a portion of a picture consisting of macroblocks that are independent of macroblocks in the same picture.

[0050] In some examples, the motion estimation unit 204 may perform unidirectional prediction on the current video block, and the motion estimation unit 204 may search the reference pictures of list 0 or list 1 to find the reference video block for the current video block. The motion estimation unit 204 may then generate a reference index and a motion vector, the reference index indicating the reference picture in list 0 or list 1 containing the reference video block, and the motion vector indicating the spatial displacement between the current video block and the reference video block. The motion estimation unit 204 may output the reference index, the prediction direction indicator, and the motion vector as the motion information of the current video block. The motion compensation unit 205 may generate a predicted video block for the current video block based on the reference video block indicated by the motion information of the current video block.

[0051] Alternatively, in other examples, the motion estimation unit 204 may perform bidirectional prediction on the current video block. The motion estimation unit 204 may search the reference pictures in list 0 to find a reference video block for the current video block, and may also search the reference pictures in list 1 to find another reference video block for the current video block. The motion estimation unit 204 may then generate a plurality of reference indexes and a plurality of motion vectors, the plurality of reference indexes indicating a plurality of reference pictures in list 0 and list 1 containing a plurality of reference video blocks, and the plurality of motion vectors indicating a plurality of spatial displacements between the plurality of reference video blocks and the current video block. The motion estimation unit 204 may output the plurality of reference indexes and the plurality of motion vectors of the current video block as the motion information of the current video block. The motion compensation unit 205 may generate a predicted video block for the current video block based on the plurality of reference video blocks indicated by the motion information of the current video block.

[0052] In some examples, motion estimation unit 204 may output a complete set of motion information for use in a decoding process by a decoder. Alternatively, in some embodiments, motion estimation unit 204 may signal motion information of a current video block with reference to motion information of another video block. For example, motion estimation unit 204 may determine that motion information of a current video block is sufficiently similar to motion information of a neighboring video block.

[0053] In one example, motion estimation unit 204 may indicate a value in a syntax structure associated with the current video block that indicates to video decoder 300 that the current video block has the same motion information as another video block.

[0054] In another example, the motion estimation unit 204 may identify another video block and a motion vector difference (MVD) in a syntax structure associated with the current video block. The motion vector difference indicates the difference between the motion vector of the current video block and the motion vector of the indicated video block. The video decoder 300 may use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

[0055] As discussed above, the video encoder 200 may signal motion vectors in a predictive manner.Two examples of prediction signaling techniques that may be implemented by the video encoder 200 include Advanced Motion Vector Prediction (AMVP) and Merge mode signaling.

[0056] The intra prediction unit 206 may perform intra prediction on the current video block. When the intra prediction unit 206 performs intra prediction on the current video block, the intra prediction unit 206 may generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a prediction video block and various syntax elements.

[0057] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a minus sign) the predicted video block(s) of the current video block from the current video block. The residual data of the current video block may include residual video blocks corresponding to different sample components of samples in the current video block.

[0058] In other examples, such as in skip mode, there may be no residual data for the current video block, and the residual generation unit 207 may not perform a subtraction operation.

[0059] Transform processing unit 208 may generate one or more transform coefficient video blocks for a current video block by applying one or more transforms to the residual video block associated with the current video block.

[0060] After transform processing unit 208 generates a transform coefficient video block associated with the current video block, quantization unit 209 may quantize the transform coefficient video block associated with the current video block based on one or more quantization parameter (QP) values ​​associated with the current video block.

[0061] The inverse quantization unit 210 and the inverse transform unit 211 may apply inverse quantization and inverse transform to the transform coefficient video block, respectively, to reconstruct a residual video block from the transform coefficient video block. The reconstruction unit 212 may add the reconstructed residual video block to corresponding samples from one or more prediction video blocks generated by the prediction unit 202 to generate a reconstructed video block associated with the current video block for storage in the buffer 213.

[0062] After reconstruction unit 212 reconstructs the video block, a loop filtering operation may be performed to reduce video blocking artifacts in the video block.

[0063] The entropy encoding unit 214 may receive data from other functional components of the video encoder 200. When the entropy encoding unit 214 receives the data, the entropy encoding unit 214 may perform one or more entropy encoding operations to generate entropy-encoded data and output a bitstream including the entropy-encoded data.

[0064] Figure 3 is a block diagram showing an example of a video decoder 300 according to some embodiments of the present disclosure, which may be Figure 1 An example of a video decoder 124 in the system 100 is shown.

[0065] Video decoder 300 may be configured to perform any or all of the techniques of this disclosure. Figure 3 In the example of , video decoder 300 includes multiple functional components. The techniques described in this disclosure can be shared between the various components of video decoder 300. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0066] exist Figure 3 In the example of , the video decoder 300 includes an entropy decoding unit 301, a motion compensation unit 302, an intra prediction unit 303, an inverse quantization unit 304, an inverse transform unit 305, and a reconstruction unit 306 and a buffer 307. In some examples, the video decoder 300 can perform a decoding process that is generally opposite to the encoding process described with respect to the video encoder 200.

[0067] The entropy decoding unit 301 can retrieve the encoded bitstream. The encoded bitstream may include entropy encoded video data (e.g., encoded blocks of video data). The entropy decoding unit 301 can decode the entropy encoded video data, and the motion compensation unit 302 can determine motion information from the entropy decoded video data, the motion information including motion vectors, motion vector precision, reference picture list indexes, and other motion information. The motion compensation unit 302 can determine such information, for example, by performing AMVP and Merge mode. AMVP is used, including deriving several most likely candidates based on data and reference pictures from adjacent PBs. The motion information typically includes horizontal motion vector displacement values ​​and vertical motion vector displacement values, one or two reference picture indexes, and in the case of prediction areas in B strips, also includes an identification of which reference picture list is associated with each index. As used herein, in some aspects, "Merge mode" may refer to deriving motion information from spatial neighboring blocks or temporal neighboring blocks.

[0068] The motion compensation unit 302 may generate a motion compensated block, possibly performing interpolation based on an interpolation filter.Identifiers for the interpolation filters used with sub-pixel precision may be included in the syntax elements.

[0069] The motion compensation unit 302 may calculate interpolated values ​​for sub-integer pixels of a reference block using interpolation filters used by the video encoder 200 during encoding of the video block. The motion compensation unit 302 may determine the interpolation filters used by the video encoder 200 based on received syntax information, and the motion compensation unit 302 may use the interpolation filters to generate a prediction block.

[0070] The motion compensation unit 302 may use at least part of the syntax information to determine the size of blocks used to encode (multiple) frames and / or (multiple) slices of the encoded video sequence, partition information describing how each macroblock of a picture of the encoded video sequence is partitioned, a mode indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter-coded block, and other information for decoding the encoded video sequence. As used herein, in some aspects, a "slice" may refer to a data structure that can be decoded independently of other slices of the same picture in terms of entropy coding and decoding, signal prediction, and residual signal reconstruction. A slice may be an entire picture, or it may be a region of a picture.

[0071] The intra prediction unit 303 may use, for example, an intra prediction mode received in the bitstream to form a prediction block from spatially neighboring blocks. The inverse quantization unit 304 inverse quantizes (i.e., dequantizes) the quantized video block coefficients provided in the bitstream and decoded by the entropy decoding unit 301. The inverse transform unit 305 applies an inverse transform.

[0072] The reconstruction unit 306 may obtain the decoded block, for example, by adding the residual block to the corresponding prediction block generated by the motion compensation unit 302 or the intra prediction unit 303. If necessary, a deblocking filter may also be applied to filter the decoded block to remove blocking artifacts. The decoded video block is then stored in a buffer 307, which provides reference blocks for subsequent motion compensation / intra prediction, and the buffer 307 also generates the decoded video for presentation on a display device.

[0073] Some exemplary embodiments of the present disclosure will be described in detail below. It should be noted that the section titles used in this document are for ease of understanding, and the embodiments disclosed in the section are not limited to that section. In addition, although some embodiments are described with reference to multifunctional video codecs or other specific video codecs, the disclosed technology is also applicable to other video coding and decoding technologies. In addition, although some embodiments describe the video encoding steps in detail, it should be understood that the corresponding decoding steps of de-encoding will be implemented by the decoder. In addition, the term video processing includes video encoding or compression, video decoding or decompression, and video transcoding, in which video pixels are represented from one compression format to another compression format or at different compression bit rates. 1. Overview The present disclosure relates to video coding techniques. Specifically, it relates to intra-frame block copying (IBC), how and / or whether to combine IBC with local illumination compensation and other coding tools in image / video coding. It can be applied to existing video coding standards such as HEVC or Versatile Video Codec (VVC). It can also be applied to future video coding standards or video codecs. 2. Introduction Video codec standards have evolved primarily through the development of the well-known ITU-T and ISO / IEC standards. ITU-T developed H.261 and H.263, ISO / IEC developed MPEG-1 and MPEG-4 Visual, and the two organizations jointly developed H.262 / MPEG-2 Video and H.264 / MPEG-4 Advanced Video Codec (AVC) and H.265 / HEVC standards. Since H.262, video codec standards have been based on a hybrid video codec structure, which uses temporal prediction plus transform codec. In order to explore future video codec technologies after HEVC, the Joint Video Exploration Team (JVET) was jointly established by VCEG and MPEG in 2015. Since then, JVET has adopted many new methods and put them into reference software called the Joint Exploration Model (JEM). In April 2018, the Joint Video Experts Group (JVET) between VCEG (Q6 / 16) and ISO / IEC JTC1 SC29 / WG11 (MPEG) was created to work on the VVC standard, which aims to reduce bitrate by 50% compared to HEVC. 2.1 Encoding and decoding process of typical video codecs Figure 4 An example of an encoder block diagram for VVC is shown, which contains three loop filter blocks: deblocking filter (DF), sample adaptive offset (SAO) and ALF. Unlike DF, which uses a predefined filter, SAO and ALF use the original samples of the current picture to add compensation and reduce the mean square error between the original samples and the reconstructed samples by applying a finite impulse response (FIR) filter, respectively, where the compensation and filter coefficients are transmitted by signaling through the codec side information. ALF is located at the last processing stage of each picture and can be seen as a tool that attempts to capture and repair artifacts created by previous stages. 2.2 Intra-mode codec with 67 intra-prediction modes Figure 5 67 intra prediction modes are shown. To capture arbitrary edge directions present in natural video, as used in HEVC, the number of directional intra modes is extended from 33 to 65, as shown in Figure 5 As shown, planar and DC modes remain unchanged. These more intensive directional intra prediction modes apply to all block sizes and both luma and chroma intra prediction. In HEVC, each intra-coded block has a square shape, and the length of each side of the square is a power of 2. Therefore, no division operation is required to generate the intra predictor using DC mode. In VVC, blocks can have a rectangular shape, which in general requires the use of a division operation for each block. To avoid division operations for DC prediction, only the longer sides are used to calculate the average value of non-square blocks. 2.2.1 Wide-angle intra prediction Although 67 modes are defined in VVC, the exact prediction direction for a given intra prediction mode index also depends on the block shape. Conventional angular intra prediction directions are defined as 45 degrees to -135 degrees clockwise. In VVC, for non-square blocks, several conventional angular intra prediction modes are adaptively replaced with wide-angle intra prediction modes. The replaced mode is signaled using the original mode index, which is remapped to the index of the wide-angle mode after parsing. The total number of intra prediction modes remains unchanged, i.e. 67, and the intra mode encoding and decoding method remains unchanged. Fig. 6A and Figure 6B The reference samples for wide angle intra prediction are shown in Figure 1. To support these prediction directions, a top reference of length 2W+1 and a left reference of length 2H+1 are provided as shown in Figure 1. Fig. 6A and Figure 6B is defined as shown. Fig. 6A and Figure 6B Reference samples for wide-angle intra prediction are shown. The number of modes replaced in the wide direction mode depends on the aspect ratio of the block. The replaced intra prediction modes are shown in Table 1. Table 1 - Intra-prediction modes replaced by wide-angle mode like Figure 7 As shown, in the case of wide-angle intra prediction, two vertically adjacent prediction samples can use two non-adjacent reference samples. Therefore, a low-pass reference sample filter and side smoothing are applied to wide-angle prediction to reduce the negative impact of the increased gap Δpα. If the wide-angle mode represents a non-fractional offset. There are 8 modes in the wide-angle mode that meet this condition, and these modes are [-14, -12, -10, -6, 72, 76, 78, 80]. When the block is predicted by these modes, the samples in the reference cache are directly copied without applying any interpolation. With this modification, the number of samples that need to be smoothed is reduced. In addition, it aligns the design of non-fractional modes in traditional prediction mode and wide-angle mode. In VVC, 4:2:2 and 4:4:4 as well as 4:2:0 chroma formats are supported. The chroma derivation mode (DM) derivation table for the 4:2:2 chroma format was originally ported from HEVC, which expanded the number of entries from 35 to 67 to align with the expansion of intra prediction modes. Since the HEVC specification does not support prediction angles below -135 degrees and above 45 degrees, the luma intra prediction modes ranging from 2 to 5 are mapped to 2. Therefore, the chroma DM derivation table for the 4:2:2 chroma format is updated by replacing some values ​​of the entries of the mapping table to more accurately convert the prediction angles of the chroma blocks. 2.3 Inter-frame prediction For each inter-predicted CU, motion parameters consisting of motion vector, reference picture index and reference picture list usage index, as well as additional information required by the new codec features of VVC for sample generation used for inter-prediction. Motion parameters can be signaled explicitly or implicitly. When a CU is coded and decoded in skip mode, the CU is associated with one PU and has no significant residual coefficients, no coded motion vector increments or reference picture indexes. Merge mode is specified, whereby the motion parameters of the current CU are obtained from neighboring CUs, which include spatial and temporal candidates, as well as additional arrangements introduced in VVC. Merge mode can be applied to any inter-predicted CU, not just skip mode. An alternative to Merge mode is explicit transmission of motion parameters, where motion vectors, corresponding reference picture indexes for each reference picture list and reference picture list usage flags, as well as other required information, are explicitly signaled for each CU. 2.4 Intra-block copy (IBC) Intra-block copying (IBC) is a tool adopted in the HEVC extension on SCC. It is well known that it significantly improves the coding efficiency of screen content materials. Since the IBC mode is implemented in a block-level coding mode, block matching (BM) is performed at the encoder to find the best block vector (or motion vector) for each CU. Here, the block vector is used to indicate the replacement from the current block to the reference block, which has been reconstructed in the current picture. The luminance block vector of the IBC-coded CU is integer precision. The chrominance block vector is also rounded to integer precision. When combined with AMVR, the IBC mode can switch between 1-pixel and 4-pixel motion vector precision. The IBC-coded CU is regarded as a third prediction mode in addition to the intra or inter prediction mode. The IBC mode is applicable to CUs with a width and height of less than or equal to 64 luminance samples. At the encoder side, hash-based motion estimation is performed for IBC. The encoder performs RD checks on blocks with a width or height no greater than 16 luma samples. For non-Merge mode, a block vector search is first performed using a hash-based search. If the hash search does not return a valid candidate, a local search based on block matching is performed. In hash-based search, the hash key match (32-bit CRC) between the current block and the reference block is extended to all allowed blocks. The hash key calculation for each position in the current picture is based on 4×4 sub-blocks. For current blocks of larger sizes, the hash key is determined to match the hash key of the reference block when all hash keys of all 4×4 sub-blocks match the hash keys of the corresponding reference positions. If the hash keys of multiple reference blocks are found to match the hash key of the current block, the block vector cost of each matching reference is calculated and the one with the smallest cost is selected. In the block matching search, the search range is set to cover the previous and current CTUs. At the CU level, the IBC mode is signaled using a flag. The IBC mode can be signaled as IBC AMVP mode or IBC Skip / Merge mode as shown below: -IBC Skip / Merge mode: The Merge candidate index is used to indicate which block vector from the list of neighboring candidate IBC codec blocks is used to predict the current block. The Merge list consists of spatial candidates, HMVP candidates and pairwise candidates. - IBC AMVP mode: Block vector differences are encoded in the same way as motion vector differences. The block vector prediction method uses two candidates as predictors, one from the left neighbor and one from the top neighbor (if IBC encoding). When any neighbor is not available, the default block vector will be used as predictor. A flag is signaled to indicate the block vector predictor index. 2.5 Merge Mode with MVD (MMVD) In addition to the Merge mode that uses implicitly derived motion information directly for prediction sample generation of the current CU, the Merge mode with motion vector difference (MMVD) is introduced in VVC. The MMVD flag is signaled immediately after the regular Merge flag is sent to specify whether the MMVD mode is used for the CU. In MMVD, after the Merge candidate is selected, it is further refined by the MVD information transmitted by the signal. Further information includes the Merge candidate flag, an index specifying the motion amplitude, and an index indicating the motion direction. In MMVD mode, one of the first two candidates in the Merge list is selected to be used as the MV basis. The MMVD candidate flag is transmitted by a signal to specify which one between the first and second Merge candidates is used. Figure 8 A diagram showing motion vector scaling for temporal Merge candidates is shown. Fig.9A and Fig. 9B An example of an MMVD search point is shown. The distance index specifies the motion magnitude information and indicates a predefined offset from the starting point. Fig.9A and Fig. 9B As shown, the offset is added to the horizontal component or the vertical component of the starting MV. The relationship between the distance index and the predefined offset is specified in Table 2. Table 2 Relationship between distance index and predefined offset The direction index indicates the direction of the MVD relative to the starting point. The direction index can indicate four directions, as shown in Table 3. Note that the meaning of the MVD symbol can change depending on the information of the starting MV. When the starting MV is a non-predicted MV or a bidirectionally predicted MV, where both lists point to the same side of the current picture (i.e., both referenced POCs are greater than the POC of the current picture, or both are less than the POC of the current picture), the symbol in Table 3 specifies the sign of the MV offset added to the starting MV. When the starting MV is a bidirectionally predicted MV, where the two MVs point to different sides of the current picture (i.e., the POC of one reference is greater than the POC of the current picture, and the POC of the other reference is less than the POC of the current picture), and the difference in POC in List 0 is greater than the difference in POC in List 1, the symbol in Table 3 specifies the sign of the MV offset added to the MV component of the starting MV of List 0, and the sign for List 1 MV has the opposite value. Otherwise, if the difference in POC in List 1 is greater than that in List 0, the symbol in Table 3 specifies the sign of the MV offset added to the List 1 MV component of the starting MV and the sign for List 0 MV has the opposite value. The MVD is scaled according to the difference in POC in each direction. If the POC difference in both lists is the same, no scaling is required. Otherwise, if the POC difference in list 0 is greater than the POC difference in list 1, the MVD for list 1 is scaled by defining the POC difference of L0 as td and the POC difference of L1 as tb, as Figure 8 If the POC difference of L1 is greater than L0, the MVD for list 0 is scaled in the same way. If the starting MV is unidirectionally predicted, the MVD is added to the available MVs. Table 3 - Sign of MV offset specified by direction index Direction Index 00 01 10 11 x-axis + - N / A N / A y-axis N / A N / A + - 2.6 Local Illumination Compensation (LIC) Local illumination compensation (LIC) is a codec tool that addresses the problem of local brightness variations between a current picture and its temporal reference picture. LIC is based on a linear model where a scaling factor and an offset are applied to a reference sample to obtain a predicted sample for the current block. Specifically, LIC can be mathematically modeled by the following equation: P(x, y) = α·P r (x+v x ,y+v y )+β Where P(x, y) is the prediction signal of the current block at the coordinate (x, y); P r (x+v x ,y+v y ) is the motion vector (v x , v y ) points to the reference block; and α and β are the corresponding scaling factors and offsets applied to the reference block. Fig.10 The LIC process is shown. Fig.10 An example of local illumination compensation is shown. Fig.10 In , when applying LIC to a block, the minimum mean square error (LMSE) method is used to minimize the neighboring samples of the current block (i.e. Fig.10 The template T in the temporal reference picture) and its corresponding reference sample point in the temporal reference picture (ie, Fig.10 In addition, in order to reduce the computational complexity, both the template samples and the reference template samples are subsampled (adaptive subsampling) to derive the LIC parameters, i.e., only Fig.10 The shaded points in are used to derive α and β. Fig.11 In order to improve the encoding and decoding performance, the short edge is not subsampled. Fig.11 shown. 2.7 IBC with Template Matching It is proposed to use template matching with IBC also for both IBC Merge mode and IBC AMVP mode. Compared to the Merge list used by the conventional IBC Merge mode, the IBC-TM Merge list has been modified so that candidates are selected according to a deduplication method with motion distances between candidates as in the conventional TM Merge mode. The ending zero motion completion (which is meaningless with respect to intra coding) has been replaced by the motion vectors to the left (-W, 0) CU, the top (0, -H) CU, and the top-left (-W, -H) CU, and then the list is completed with the left CU without deduplication if necessary. In IBC-TMMerge mode, the selected candidates are refined with template matching methods before RDO or decoding process.IBC-TM Merge mode has been made competitive with the regular IBC Merge mode and the TM Merge flag is signaled. In IBC-TM AMVP mode, up to 3 candidates are selected from the IBC Merge list. Each of these 3 selected candidates is refined using a template matching method and ranked according to their resulting template matching cost. Only the first 2 are then typically considered in the motion estimation process. Fig.12 The IBC reference area depending on the current CU position is shown. Template matching refinement for both IBC-TM Merge and AMVP modes is very simple, since IBC motion vectors are constrained to be integers and are Fig.12 . Therefore, in IBC-TM Merge mode, all refinements are performed with integer precision, and in IBC-TM AMVP mode, refinements are performed with integer or 4-pixel precision. In both cases, the refined motion vectors in each refinement step must obey the constraints of the reference region. 2.8 IBC Merge Mode with Block Vector Difference The IBC Merge mode with block vector difference is shown below. The distance set is {1 pixel, 2 pixels, 4 pixels, 8 pixels, 12 pixels, 16 pixels, 24 pixels, 32 pixels, 40 pixels, 48 ​​pixels, 56 pixels, 64 pixels, 72 pixels, 80 pixels, 88 pixels, 96 pixels, 104 pixels, 112 pixels, 120 pixels, 128 pixels}, and the BVD directions are two horizontal directions and two vertical directions. The base candidate is selected from the first five candidates in the reordered IBC Merge list. And all possible MBVD refinement positions (20x4) for each base candidate are reordered based on the SAD cost between the template (one row above the current block and one column to the left) and the reference of each refinement position. Finally, the first 8 refinement positions with the lowest template SAD cost are kept as available positions and are therefore used for MBVD index encoding and decoding. 2.9 Reconstruction Reordering IBC (RR-IBC) Screen content codec tools such as intra block copy (IBC) generate prediction blocks by directly copying previously coded reference areas in the same picture. Fig.13 An example of symmetry in a screen content picture is shown. Symmetry is often observed in video content, especially in text character areas and computer-generated graphics in screen content sequences, such as Fig.13 Therefore, a screen content-specific codec that takes symmetry into account will effectively compress such video content. A reconstruction-reordering IBC (RR-IBC) mode is proposed for screen content video coding and decoding. When applied, the samples in the reconstructed block are flipped according to the flip type of the current block. On the encoder side, the original block is flipped before motion search and residual calculation, while the prediction block is derived without flipping. On the decoder side, the reconstructed block is flipped to restore the original block. For RR-IBC codec blocks, two flipping methods are supported, namely horizontal flipping and vertical flipping. First, a syntax flag for the IBC AMVP coded block is transmitted by signaling, indicating whether the reconstruction is flipped, and if it is flipped, another flag specifying the flipping type is further transmitted by signaling. For IBC Merge, the flipping type is inherited from the neighboring block without syntax signaling. Taking into account horizontal or vertical symmetry, the current block and the reference block are usually aligned horizontally or vertically. Therefore, when horizontal flipping is applied, the vertical component of BV is not transmitted by signaling and is presumed to be equal to 0. Similarly, when vertical flipping is applied, the horizontal component of BV is not transmitted by signaling and is presumed to be equal to 0. Fig.14A A diagram showing BV adjustment for horizontal flipping is shown. Fig. 14B , a diagram of BV adjustment for vertical flipping is shown. In order to better exploit the symmetry property, a flip-aware BV adjustment method is applied to refine the block vector candidates. Fig.14A and Fig. 14B As shown, (x nbr ,y nbr ) and (X cur ,y cur ) represent the coordinates of the center sample points of the neighboring blocks and the current block, BV nbr and BV cur Denote the BV of the neighboring block and the current block respectively. Instead of inheriting the BV directly from the neighboring block, in the case where the neighboring block is coded with horizontal flipping, the motion shift is added to the BV nbr The horizontal component (expressed as BV nbr h ) to calculate BV cur The horizontal component of BV nbr h =2(x nbr -x cur )+BV nbr h Similarly, in the case where the neighboring block is coded with vertical flipping, the motion shift is added to BV nbr The vertical component (expressed as BV nbr v ) to calculate BV cur Vertical component, or BV cur v =2(ynbr -y cur )+BV nbr v . 2.10 Intra-frame Template Matching Intra-frame template matching prediction (IntraTMP) is a special intra-frame prediction mode that copies the best prediction block from the reconstructed part of the current frame. The L-shaped template predicted by intra-frame template matching matches the current template. For a predefined search range, the encoder searches for the template most similar to the current template in the reconstructed part of the current frame and uses the corresponding block as the prediction block. The encoder then signals the use of this mode and the same prediction operation is performed on the decoder side. Fig.15 The intra-frame template matching search area is shown in FIG. By comparing the L-shaped causal neighboring block of the current block with the one composed of Fig.15 Generate a prediction signal by matching another block in a predefined search area: R1: current CTU, R2: Upper left CTU, R3: Upper CTU, R4: Left CTU. SAD is used as the cost function. In each region, the decoder searches for the template with the minimum SAD relative to the current one and uses its corresponding block as the prediction block. The size of all regions (SearchRange_w, SearchRange_h) is set proportionally to the block size (BlkW, BlkH) so that each pixel has a fixed number of SAD comparisons. That is: SearchRange_w=a*BlkW SearchRange_h=a*BlkH Where "a" is a constant that controls the gain / complexity tradeoff. In practice, "a" is equal to 5. The intra template matching tool is enabled for CUs with dimensions in width and height less than or equal to 64. This maximum CU size for intra template matching is configurable. When DIMD is not used for the current CU, the intra template matching prediction mode is signaled at the CU level through a dedicated flag. 3. Question In the current design of IBC, the entire block is directly copied from the reconstruction area in the current picture. However, the encoding and decoding efficiency of IBC may be limited when illumination changes occur within the current picture. 4. Detailed solution The following detailed embodiments should be considered as examples to explain the general concept. These embodiments should not be interpreted in a narrow manner. In addition, these embodiments can be combined in any way. In the present disclosure, intra block copy (IBC) may not be limited to the current IBC technology, but may be interpreted as a technology in which a reference block (or prediction block) is obtained using samples in the current slice / slice / sub-picture / picture / other video unit (e.g., CTU row), excluding conventional intra prediction methods. In the present disclosure, local illumination compensation (LIC) may not be limited to the current LIC technology. LIC may refer to an inter-frame prediction technique that models the local illumination variation between a current block and its prediction block as a function of the local illumination variation between a current block template and a reference block template. The parameters of the function may be represented by a linear equation (e.g., α×p[x]+β) or a nonlinear equation. In the present disclosure, CIBCIP (or IBC-CIIP) may refer to a codec combining intra block copy (IBC) and intra prediction. It is a codec that uses both IBC and intra prediction to obtain predictions for blocks. In this disclosure, IBC-GPM may refer to a codec tool that uses IBC in a video unit to obtain prediction of at least one sub-partition when the video unit is geometrically partitioned into more than one sub-partition. In the following discussion, IBC may be replaced by other codec tools that rely on encoded / decoded / reconstructed information within the same region, eg, color palette, intra template matching. IBC with LIC 1. It is proposed that the refined prediction samples can be derived as f(p[x]), where p[x] represents the prediction samples of a video unit and f is any function. a. In one example, f(p[x])=α×p[x]+β, where α and β represent parameters of the linear equation. b. In one example, the function or at least one parameter of the function may be derived based on a template of the current block. c. In one example, the predicted sample point can be derived through IBC. i. In one example, the function or at least one parameter of the function may be derived based on a template of a reference block of the current block, where the reference block may be located by a block vector (BV). 2. It is proposed that LIC can be applied to compensate for the prediction (reconstruction) of video units, where IBC is used to obtain the prediction (reconstruction) of video units. It is denoted as IBC-LIC. a. In one example, linear or non-linear equations / models may be used in IBC-LIC to compensate for the prediction of video units. i. In one example, the linear equation may be α×p[x]+β, where p[x] represents the prediction of the video unit, and α and β represent parameters of the linear equation. b. In one example, the parameters of the equations used in IBC-LIC may be pre-defined or signaled in the bitstream. c. In one example, the parameters of the equations used in IBC-LIC can be derived using codec information. i. In one example, the current template is reconstructed from the neighboring video units (adjacent or non-adjacent) The sample points are composed of a reference template and can be used to derive parameters. Fig.16 Shown in. 1) In one example, a reference template may be derived using the BV for obtaining a prediction of a video unit. 2) In one example, part or all of the samples of the reference template and the current template may be used to derive parameters. 3) In one example, a least square error method may be used to derive parameters. ii. In one example, how to derive parameters using the current template and the reference template may be the same as that of LIC for inter prediction. d. In one example, part or all of the prediction samples of a video unit may be compensated using IBC-LIC. 3. In one example, IBC-LIC can be applied in IBC AMVP mode and / or IBC Merge mode. a. In one example, the IBC AMVP mode may refer to normal IBC AMVP, or TM-based IBC AMVP, or RR-IBC AMVP mode, or CIBCIP (IBC-CIIP), or IBC-GPM, or other IBC AMVP modes in which a BV prediction value is derived and a BVD is transmitted / derived via a signal. b. In one example, the IBC Merge mode may refer to a normal IBC Merge mode, or an IBC-TM Merge mode, or an IBC-MBVD mode, or a CIBCIP (IBC-CIIP), or an IBC-GPM. i. In one example, IBC-LIC may be applied to specific IBC Merge candidate types. ii. In another example, IBC-LIC may not be allowed to apply to certain IBC Merge candidate types. 1) In one example, the Merge candidate type may refer to a RR-IBC candidate. c. Alternatively, IBC-LIC may not be allowed to be applied to one or more of the above IBC codecs. i. In one example, the IBC codec tool may refer to RR-IBC, or CIBCIP (IBC-CIIP), or IBC-GPM. d. In one example, whether and / or how to apply IBC-LIC for IBC AMVP mode and / or IBC Merge mode may be signaled or determined using codec information. e. In one example, one or more syntax elements may be signaled to indicate whether and / or how to apply IBC-LIC for IBCAMVP mode and / or IBC Merge mode. f. In one example, whether and / or how the IBC-LIC is applied for the IBC Merge mode may be inherited. i. In one example, the inheritance of whether to apply IBC-LIC and / or how to apply IBC-LIC can be associated with a Merge candidate. 1) In one example, when the merge candidate is a specific merge type, IBC- LIC can be disabled. a) In one example, the specific type may refer to RR-IBC. 4. In one example, whether and / or how to apply the IBC-LIC may depend on coded information including: a. Block dimensions and / or block size b. The encoded information may refer to the depth of the block. c. Slice / picture type and / or partition tree type (single tree, dual tree, or partial dual tree) i. In one example, IBC-LIC may be applied only to I slices / pictures. d. Block location e. Quantization parameters f. Color component. 5. In one example, more than one LIC equation may be used to compensate for the prediction (reconstruction) of a video unit derived using IBC. a. In one example, multiple LIC types may refer to different LIC equations with adjustment parameters for one or more existing parameters (eg, α and β) of the LIC. i. In one example, an adjustment parameter may be used to adjust α, such as α+u or α×u. ii. In one example, an adjustment parameter may be used to adjust β, such as β+v or β×v. b. In one example, parameters for more than one LIC equation can be derived using different templates. i. In one example, different sample point lines of the template may be used. ii. In one example, a left, or top, or upper left template may be used. iii. In one example, samples from different locations in the template may be used. 1) In one example, the position may refer to a downsampling position. i v In one example, samples from different categories may be used. 1) In one example, different categories can be classified depending on the samples of the template. 2) In one example, the average value of the samples in the template is used to derive different categories. c. In one example, whether to apply one LIC equation among more than one LIC equations and how to apply one LIC equation among more than one LIC equations can be indicated using syntax elements, which are indicated in the bitstream. d. In one example, whether to apply one of the more than one LIC equations and how to apply one of the more than one LIC equations can be adaptively determined. 6. In one example, the position / shape of the template may depend on the codec information. a. In one example, if the left neighboring sample point is not available, the template only contains the upper neighboring sample points. b. In one example, if the upper neighboring sample point is not available, the template only contains the left neighboring sample points. c. In one example, if the left and upper neighboring sample points are not available, IBC-LIC may not be applicable. d. In one example, the template may refer to a template of a current block or a reference block. e. In one example, the position / shape of the template may depend on whether RR-IBC or normal IBC is applied. f. In one example, the position / shape of the template can be composed of one or more point lines. g. In one example, the position / shape of the template may be pre-defined, transmitted via a signal, or derived on the fly. h. In one example, the position / shape of the template may depend on the width and height of the video unit. i. In one example, the reference template may be constrained in an IBC cache. i. Alternatively, the reference template may not be constrained in the IBC cache. 7. The determination of whether a block is allowed to be encoded and decoded using the IBC-LIC mode may depend on the encoded and decoded information, which includes: a. Block dimension and / or block size. i. In one example, when the block size (W×H) is less than or equal to a threshold (T), the block is allowed to be encoded and decoded using the IBC-LIC mode, where W and H represent the block width and block height, respectively. 1) In one example, T = 256, or 512, or 1024, or 2048, or 4096 b. Depth of the block. c. Block location. d. Strip / Picture Type. e. Temporal layer (eg, temporal layer index). f. Color format. g. Color component. 8. In one example, whether and / or how to apply IBC-LIC may depend on the color format and / or color components. a. In one example, IBC-LIC can be applied to all color components. b. In one example, whether to apply the IBC-LIC to the first component and / or how to apply the IBC-LIC to the first component may depend on whether to apply the IBC-LIC to the second component. i. In one example, the first component may refer to a chrominance component (eg, Cb and / or C r ), and the second component can refer to the brightness component (e.g., Y). ii. In one example, the IBC-LIC may be applied to the first component in the same manner as the second component. 1) Alternatively, the way in which IBC-LIC is applied to the first component may be different from that to the second component. c. In one example, IBC-LIC may be applied to the luma component but not to the chroma components. i. In one example, the luminance component may refer to Y or RGB in the YCbCr color space G in color space. ii. In one example, the chrominance component may refer to Cb and / or C r Or R and / or B in RGB color space. Signaling of IBC-LIC 9. The indication of IBC-LIC mode may be conditionally signaled, where the condition may include: a. Whether a specific codec is allowed, such as IBC (IBC AMVP or IBC Merge), or RR-IBC, or CIBCIP (IBC-CIIP), or IBC-TM, or IBC-GPM b. Block dimensions and / or block size c. Block Depth d. Strip / picture type and / or partition tree type (single tree or dual tree or partial dual tree) e. Time domain layer identification f. Block location g. Color component. 10. Whether the current block is coded or decoded using the IBC-LIC mode may be signaled using one or more syntax elements. a. In one example, the syntax element may be binarized using fixed length codec, or truncated unary codec, or unary codec, or EG codec, or a codec flag. b. In one example, the syntax element may be bypass coded or context coded. i. The context may depend on coded information, such as block dimensions and / or block size, and and / or slice / picture type, and / or information of neighboring blocks (adjacent or non-adjacent), and / or information of other coding tools used for the current block, and / or information of the time domain layer. 1) In one example, the context may depend on whether the neighboring block utilizes IBC-LIC To encode and decode. c. In one example, when the current video unit is coded by IBC, an indication of the IBC-LIC mode may be signaled. d. In one example, syntax elements may be signaled before or after the indication of a specific codec tool. i. In one example, a specific codec may refer to RR-IBC mode, or IBC-TM mode, or IBC-MBVD mode, or CIBCIP (IBC-CIIP), or IBC-GPM. ii. In one example, whether and / or how the syntax elements are transmitted through signals may depend on whether IBC mode, RR-IBC mode, or IBC-TM mode, or IBC-MBVD mode, or CIBCIP (IBC-CIIP), or IBC-GPM is enabled for the video unit. iii. In one example, the syntax element may be signaled following the indication of the RR-IBC mode. 1) In one example, when RR-IBC mode is applied, the syntax element indicating IBC-LIC is not signaled and is set to a default value, which indicates IBC- LIC is not applied. iv. In one example, when the video unit is in IBC AMVP mode, the syntax elements may be transmitted via a signal. e. In one example, one or more syntax elements may be signaled in a sequence header / picture header / SPS / VPS / DPS / DCI / PPS / APS / slice header / slice group header. f. In one example, syntax elements may be encoded and decoded in a predictive manner. g. For example, the syntax elements of the current block can be predicted from the syntax elements of neighboring blocks. General 11. In the above examples, a video unit may refer to a color component / sub-picture / slice / slice / codec tree unit (CTU) / CTU row / CTU group / codec unit (CU) / prediction unit (PU) / transform unit (TU) / codec tree block (CTB) / codec block (CB) / prediction block (PB) / transform block (TB) / block / sub-block of a block / sub-region within a block / any other region containing more than one sample or pixel. 12. Whether and / or how to apply the method disclosed above can be transmitted by signal at sequence level / picture group level / picture level / slice level / slice group level, for example in sequence header / picture header / SPS / VPS / DPS / DCI / PPS / PPS / slice header / slice group header. 13. Whether and / or how the above disclosed methods can be applied to be transmitted by signals at PB / TB / CB / PU / TU / CU / VPDU / CTU / CTU row / slice / slice / sub-picture / other types of regions containing more than one sample or pixel. 14. Whether and / or how to apply the above disclosed methods may depend on the coded information, such as block size, color format, single / dual tree partitioning, color component, slice / picture type. 5. Examples 5.1 Example 1 In this contribution, three aspects are proposed to extend the use of IBC: Aspect #1: Combined IBC and intra prediction (IBC-CIIP); Aspect #2: IBC with geometric partitioning (IBC-GPM); Aspect #3: IBC with Local Illumination Compensation (IBC-LIC). Combined IBC and intra prediction (IBC-CIIP) When IBC-CIIP is applied to a CU, two prediction signals are obtained using IBC and intra prediction. The two prediction signals are weighted and summed to generate the final prediction. IBC-CIIP can be applied to IBC AMVP mode and IBC Merge mode. The CU flag is transmitted by a signal to indicate the use of IBC-CIIP. IBC with geometric partitioning (IBC-GPM) When IBC GPM is applied to a CU, the CU is geometrically divided into two sub-partitions. Prediction signals for the two sub-partitions are generated using IBC and intra prediction. IBC GPM can be applied to IBC Merge mode. A CU flag is transmitted by a signal to indicate the use of IBC GPM. IBC with Local Illumination Compensation (IBC-LIC) When IBC-LIC is applied to a CU, the local illumination variation between the CU and its prediction block is modeled as a linear equation. The parameters of the linear equation are derived similarly to the LIC for inter prediction. IBC-LIC can be applied to IBC AMVP mode and IBC Merge mode. For IBC AMVP mode, the IBC-LIC flag is transmitted by a signal to indicate the use of IBC-LIC. For IBC Merge mode, the IBC-LIC flag is inferred from the Merge candidate.

[0074] As used herein, the term "video unit" or "video block" may be a sequence, a picture, a slice, a tile, a sub-picture, a codec tree unit (CTU) / codec tree block (CTB), a CTU / CTB row, one or more codec units (CU) / codec blocks (CB), one or more CTU / CTBs, one or more virtual pipeline data units (VPDU), a sub-region within a picture / slice / slice / tile. The term "reference line" may refer to row and / or column reconstruction samples adjacent or non-adjacent to a current block, which are used to derive intra-frame prediction of the current video unit via an interpolation filter along a specific direction, and the specific direction is determined by an intra-frame prediction mode (e.g., conventional intra-frame prediction with an intra-frame prediction mode), or via reference samples of a reference line weighted by a matrix or vector to derive intra-frame prediction of the current video unit (e.g., MIP).

[0075] Fig.17 A flow chart of a method 1700 for video processing according to an embodiment of the present disclosure is shown. The method 1700 is implemented during conversion between a video unit of a video and a bitstream of the video.

[0076] At block 1710, for conversion between a video unit of video and a bitstream of video, prediction samples for the video unit are derived.

[0077] At block 1720, refined prediction samples for the video unit are derived by applying a refinement process to the prediction samples.

[0078] At block 1730, conversion is performed based on the refined prediction samples. In some embodiments, conversion may include encoding the video unit into a bitstream. Alternatively or additionally, conversion may include decoding the video unit from the bitstream. In this way, codec efficiency and codec performance can be improved.

[0079] In some embodiments, the refined prediction sample is derived as: f(p[x])=α×p[x]+β. In this case, f(p[x]) represents the refined prediction sample, p[x] represents the prediction sample, f represents the refinement process, the refinement process is a function, and α and β represent the parameters of the linear model respectively.

[0080] In some embodiments, the function of the refinement process is derived based on a template of the current block associated with the video unit.Alternatively, at least one parameter of the function of the refinement process is derived based on a template of the current block associated with the video unit.

[0081] In some embodiments, the prediction samples are derived by intra block copying (IBC). In some embodiments, the function of the refinement process or at least one parameter of the function is derived based on a template of a reference block associated with the video unit. The reference block may be located by a block vector.

[0082] In some embodiments, the refinement process includes local illumination compensation (LIC). The refined prediction samples may be obtained based on IBC with LIC.

[0083] In some embodiments, the method includes: deriving prediction samples of a video unit by applying IBC; and deriving refined prediction samples of the video unit by applying LIC to compensate the prediction samples of the video unit. For example, LIC can be applied to compensate the prediction (reconstruction) of the video unit, where IBC is used to obtain the prediction (reconstruction) of the video unit. It is denoted as IBC-LIC.

[0084] In some embodiments, a linear model is used for IBC with LIC to compensate for the prediction samples of the video unit. Alternatively, a nonlinear model is used for IBC with LIC to compensate for the prediction samples of the video unit. In some embodiments, the linear model is represented as: α×p[x]+β, where p[x] represents the prediction samples of the video unit, and α and β represent parameters of the linear model, respectively.

[0085] In some embodiments, the parameters of the model used in the IBC with LIC are predefined or indicated in the bitstream. In some embodiments, the parameters of the model used in the IBC with LIC are derived based on the codec information of the video unit.

[0086] In some embodiments, a current template including adjacent reconstructed samples of a video unit and a reference template are used to derive parameters. In one example, a current template includes adjacent reconstructed (adjacent or non-adjacent) samples of a video unit, and a reference template can be used to derive parameters. Fig.16 is shown in .

[0087] In some embodiments, the reference template is derived using BV, which is used to obtain prediction samples of the video unit. In some embodiments, a portion or all of the samples of the reference template and the current template are used to derive parameters. In some embodiments, a least square error method is used to derive parameters. In some embodiments, the method of deriving parameters using the current template and the reference template of the video unit is the same as LIC for inter-frame prediction. In some embodiments, a portion or all of the prediction samples of the video unit are compensated using IBC with LIC.

[0088] In some embodiments, IBC with LIC is applied to at least one of the following: IBC Advanced Motion Vector Prediction (AMVP) mode, or IBC Merge mode. In some embodiments, the IBC AMVP mode includes at least one of the following: normal IBC AMVP mode, template matching (TM) based IBC AMVP mode, reconstruction-reordering IBC (RR-IBC) AMVP mode, combined IBC and intra prediction (IBC-CIIP) mode, IBC with geometric partitioning mode (IBC-GPM) mode, or other IBC AMVP modes in which BV prediction values ​​are derived and block vector differences (BVDs) are indicated or derived.

[0089] In some embodiments, the IBC Merge mode includes at least one of the following: normal IBC Merge mode, IBC-TM Merge mode, IBC-Merge mode with block vector difference (MBVD) mode, IBC-CIIP mode, or IBC-GPM mode. In some embodiments, IBC with LIC is applied to the IBC Merge candidate type. Alternatively, IBC with LIC is not allowed to be applied to the IBC Merge candidate type. In some embodiments, the IBC Merge candidate type includes a RR-IBC candidate.

[0090] In some embodiments, IBC with LIC is not allowed to be applied to at least one IBC codec. In some embodiments, at least one IBC codec includes one or more of: RR-IBC, IBC-CIIP, or IBC-GPM.

[0091] In some embodiments, whether to apply IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode and / or a method of applying IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode is indicated. Alternatively, whether to apply IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode and / or a method of applying IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode is determined based on codec information of the video unit.

[0092] In some embodiments, at least one syntax element is indicated to indicate whether to apply IBC with LIC for at least one of IBC AMVP mode or IBC Merge mode and / or a method of applying IBC with LIC for at least one of IBC AMVP mode or IBC Merge mode.

[0093] In some embodiments, whether to apply IBC with LIC for IBC Merge mode and / or the method of applying IBC with LIC for IBC Merge mode is inherited. In some embodiments, inheritance of whether to apply IBC with LIC and / or the method of applying IBC with LIC is associated with Merge candidates.

[0094] In some embodiments, when the Merge candidate belongs to the target Merge type, IBC with LIC is disabled. In some embodiments, the target Merge type is RR-IBC.

[0095] In some embodiments, whether to apply IBC with LIC and / or the method of applying IBC with LIC depends on the codec information of the video unit. For example, the codec information of the video unit includes at least one of the following: block dimension, block size, depth of the video unit, slice type, picture type, partition tree type, block position, quantization parameter, or color component. In some embodiments, IBC with LIC is only applied to I slices or I pictures.

[0096] In some embodiments, the refinement process includes multiple LIC models.Multiple LIC models can be used to compensate for prediction samples of a video unit derived using IBC.

[0097] In some embodiments, multiple LIC types include different LIC models with adjustment parameters for one or more existing parameters of the LIC. In one example, multiple LIC types may refer to different LIC equations with adjustment parameters for one or more existing parameters of the LIC (eg, α and β).

[0098] In some embodiments, the adjustment parameter is used to adjust α, where α is an existing parameter of the LIC. For example, α is adjusted to α+u or α×u, where u is the adjustment parameter. In some embodiments, the adjustment parameter is used to adjust β, where β is an existing parameter of the LIC. For example, β is adjusted to β+v or β×v, where v is the adjustment parameter.

[0099] In some embodiments, parameters of multiple LIC models are derived using different templates. In some embodiments, different sample lines of the templates are used to derive parameters of multiple LIC models. In some embodiments, at least one of the following is used to derive parameters of multiple LIC models: a left template, an upper template, or an upper left template.

[0100] In some embodiments, samples from different positions in the template are used to derive parameters of multiple LIC models. In some embodiments, the different positions include downsampled positions.

[0101] In some embodiments, samples in different categories are used to derive parameters of multiple LIC models. In some embodiments, different categories are classified depending on the samples in the template. In some embodiments, the average of the samples in the template is used to derive different categories.

[0102] In some embodiments, whether to apply one LIC model among multiple LIC models and / or a method of applying one LIC model among multiple LIC models is indicated using a syntax element, and the syntax element is indicated in the bitstream. In some embodiments, whether to apply one LIC model among multiple LIC models and / or a method of applying one LIC model among multiple LIC models is adaptively determined.

[0103] In some embodiments, the position or shape of the template depends on the codec information of the video unit. In some embodiments, if the left neighboring samples are not available, the template includes only the upper neighboring samples. In some embodiments, if the upper neighboring samples are not available, the template includes only the left neighboring samples. In some embodiments, if the left and upper neighboring samples are not available, IBC with LIC is not applicable. In some embodiments, the template includes a template of the current block or a template of a reference block associated with the video unit.

[0104] In some embodiments, the position or shape of the template depends on whether RR-IBC or normal IBC is applied. In some embodiments, the position or shape of the template includes one or more sample point lines.

[0105] In some embodiments, the position or shape of the template is predefined. Alternatively, the position or shape of the template is indicated. In some other embodiments, the position or shape of the template is derived in real time. In some embodiments, the position or shape of the template depends on the width and / or height of the video unit.

[0106] In some embodiments, the reference template is constrained in the IBC cache. Alternatively, the reference template is not constrained in the IBC cache.

[0107] In some embodiments, the method further comprises: determining whether the video unit is allowed to be encoded and decoded using the IBC mode with LIC based on the encoded and decoded information of the video unit. In some embodiments, the encoded and decoded information comprises at least one of the following: block dimension, block size, depth of block, block position, slice type, picture type, temporal layer, color format, or color component.

[0108] In some embodiments, if the block size denoted as WH is less than or equal to a threshold, the video unit is allowed to be encoded and decoded using the IBC mode with LIC, where W represents the block width of the video unit and H represents the block height of the video unit. In some embodiments, the threshold is one of the following: 256, or 512, or 1024, or 2048, or 4096.

[0109] In some embodiments, whether to apply IBC with LIC and / or the method of applying IBC with LIC depends on at least one of: color format or color component. In some embodiments, IBC with LIC is applied to all color components.

[0110] In some embodiments, whether to apply IBC with LIC to the first component and / or the method of applying IBC with LIC to the first component depends on whether to apply IBC with LIC to the second component. In some embodiments, the first component includes a chrominance component (e.g., Cb and / or Cr), and the second component includes a luma component (e.g., Y).

[0111] In some embodiments, the method of applying IBC with LIC to the first component is the same as the method of applying IBC with LIC to the second component. Alternatively, the method of applying IBC with LIC to the first component is different from the method of applying IBC with LIC to the second component.

[0112] In some embodiments, IBC with LIC is applied to the luma component but not to the chroma component. In some embodiments, the luma component includes Y in the YCbCr color space or G in the RGB color space. In some embodiments, the chroma component includes at least one of the following: Cb or Cr in the YCbCr color space. Alternatively, the chroma component includes at least one of the following: R or B in the RGB color space.

[0113] In some embodiments, the indication of the IBC mode with LIC is indicated based on a condition. In some embodiments, the condition includes at least one of the following: whether the target codec method is allowed, block dimension, block size, block depth, slice type, picture type, partition tree type, temporal layer identification, block position, or color component. In some embodiments, the target codec method includes at least one of the following: IBC, IBC AMVP, IBC Merge, RR-IBC, IBC-CIIP, IBC-TM, or IBC-GPM.

[0114] In some embodiments, whether the video unit is coded using IBC mode with LIC is indicated using at least one syntax element. In some embodiments, the at least one syntax element is binarized using one of the following: fixed length codec, truncated unary codec, unary codec, EG codec, or codec flag.

[0115] In some embodiments, at least one syntax element is bypass coded or context coded. In some embodiments, the context depends on coded information of the video unit. For example, the coded information includes at least one of the following: block dimension, block size, slice type, picture type, information of neighboring blocks, information of other codecs used for the current block, or temporal layer information. In some embodiments, the context depends on whether the neighboring blocks are coded using IBC mode with LIC.

[0116] In some embodiments, if the video unit is IBC coded, an indication of IBC mode with LIC is indicated. In one example, when the current video unit is IBC coded, an indication of IBC-LIC mode may be signaled.

[0117] In some embodiments, at least one syntax element is indicated before the indication of the target codec tool.Alternatively, at least one syntax element is indicated after the indication of the target codec tool.

[0118] In some embodiments, the target codec includes at least one of the following: RR-IBC mode, IBC-TM mode, IBC-MBVD mode, IBC-CIIP, or IBC-GPM. In some embodiments, whether to indicate at least one syntax element and / or the method of indicating at least one syntax element depends on whether at least one of the following is enabled for the video unit: IBC mode, RR-IBC mode, IBC-TM mode, IBC-MBVD mode, IBC-CIIP, or IBC-GPM.

[0119] In some embodiments, at least one syntax element is indicated after the indication of the RR-IBC mode. In some embodiments, if the RR-IBC mode is applied, at least one syntax element indicating IBC with LIC is not indicated and is set to a default value, the default value indicating that IBC with LIC is not applied.

[0120] In some embodiments, at least one syntax element is indicated if the video unit is encoded using IBC-AMVP mode. In one example, the syntax element may be signaled when the video unit is in IBC AMVP mode.

[0121] In some embodiments, at least one syntax element is indicated at one of the following: a sequence header, a picture header, a sequence parameter set (SPS), a video parameter set (VPS), a dependency parameter set (DPS), decoding capability information (DCI), a picture parameter set (PPS), an adaptation parameter set (APS), a slice header, or a slice group header.

[0122] In some embodiments, at least one syntax element is coded in a predictive manner.In some embodiments, at least one syntax element of a current block of a video unit is predicted by at least one syntax element of a neighboring block.

[0123] In some embodiments, the video unit includes at least one of the following: a color component, a prediction block (PB), a transform block (TB), a codec block (CB), a prediction unit (PU), a transform unit (TU), a codec tree block (CTB), a codec unit (CU), a codec tree unit (CTU), a CTU row, a CTU group, a slice, a slice, a sub-picture, a block, a sub-region within a block, or a region containing more than one sample or pixel.

[0124] In some embodiments, an indication of whether and / or how refined prediction samples for a video unit are derived by applying a refinement process to the prediction samples is indicated at one of: a sequence level, a group of pictures level, a picture level, a slice level, or a slice group level.

[0125] In some embodiments, an indication of whether and / or how the refined prediction samples for a video unit are derived by applying a refinement process to the prediction samples is indicated in one of the following: a sequence header, a picture header, a sequence parameter set (SPS), a video parameter set (VPS), a dependency parameter set (DPS), decoding capability information (DCI), a picture parameter set (PPS), an adaptation parameter set (APS), a slice header, or a slice group header.

[0126] In some embodiments, an indication of whether and / or how the refined prediction samples for a video unit are derived by applying a refinement process to the prediction samples is indicated at one of the following: a PB, a TB, a CB, a PU, a TU, a CU, a VPDU, a CTU, a CTU row, a slice, a slice, a sub-picture, or a region containing more than one sample or pixel.

[0127] In some embodiments, whether and / or how the refined prediction samples of the video unit are derived by applying the refinement process to the prediction samples is coded information of the video unit, and wherein the coded information includes at least one of the following: block size, color format, single-tree partitioning, dual-tree partitioning, color component, slice type, or picture type.

[0128] According to another embodiment of the present disclosure, a non-transitory computer-readable recording medium is provided. The non-transitory computer-readable recording medium stores a bitstream of a video generated by a method performed by a device for video processing. The method includes: deriving prediction samples of a video unit of the video; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; and generating a bitstream based on the refined prediction samples.

[0129] According to some other embodiments of the present disclosure, a method for storing a bitstream of a video is provided. The method includes: deriving prediction samples of a video unit of the video; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; generating a bitstream based on the refined prediction samples; and storing the bitstream in a non-transitory computer-readable recording medium.

[0130] Implementations of the present disclosure may be described in view of the following items, and features of these items may be combined in any reasonable manner.

[0131] Item 1. A method of video processing, comprising: for conversion between a video unit of a video and a bitstream of the video, deriving prediction samples of the video unit; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; and performing the conversion based on the refined prediction samples.

[0132] Item 2. A method according to Item 1, wherein the refined prediction sample is derived as: f(p[x])=α×p[x]+β, wherein f(p[x]) represents the refined prediction sample, p[x] represents the prediction sample, f represents the refinement process, the refinement process is a function, and α and β represent the parameters of the linear model respectively.

[0133] Item 3. A method according to Item 1, wherein the function of the refinement process is derived based on a template of the current block associated with the video unit, or wherein at least one parameter of the function of the refinement process is derived based on the template of the current block associated with the video unit.

[0134] Item 4. The method of Item 1, wherein the prediction samples are derived by intra block copying (IBC).

[0135] Item 5. A method according to item 4, wherein the function of the refinement process or at least one parameter of the function is derived based on a template of a reference block associated with the video unit, and wherein the reference block is located by a block vector.

[0136] Item 6. The method of Item 1, wherein the refinement process includes local illumination compensation (LIC), and wherein the refined prediction samples are obtained based on IBC with LIC.

[0137] Item 7. The method of Item 6, wherein the method comprises: deriving the prediction samples of the video unit by applying the IBC; and deriving the refined prediction samples of the video unit by applying the LIC to compensate the prediction samples of the video unit.

[0138] Item 8. The method of Item 6, wherein a linear model is used for the IBC with LIC to compensate the prediction samples of the video unit, or wherein a non-linear model is used for the IBC with LIC to compensate the prediction samples of the video unit.

[0139] Item 9. The method according to Item 8, wherein the linear model is represented as: α×p[x]+β, wherein p[x] represents the predicted sample point of the video unit, and α and β represent parameters of the linear model respectively.

[0140] Clause 10. The method of clause 6, wherein parameters of a model used in the IBC with LIC are predefined or indicated in the bitstream.

[0141] Item 11. The method of Item 6, wherein parameters of a model used in the IBC with LIC are derived based on codec information of the video unit.

[0142] Item 12. A method according to Item 11, wherein a current template and a reference template comprising neighboring reconstructed samples of the video unit are used to derive the parameters.

[0143] Item 13. The method of Item 12, wherein the reference template is derived using a BV, the BV being used to obtain the prediction samples for the video unit.

[0144] Item 14. The method according to Item 12, wherein part or all of the samples of the reference template and the current template are used to derive the parameters.

[0145] Item 15. A method according to Item 12, wherein a least square error method is used to derive the parameters.

[0146] Item 16. The method of Item 6, wherein the method of deriving the parameters using the current template and the reference template of the video unit is the same as LIC for inter-frame prediction.

[0147] Item 17. The method of Item 6, wherein a portion or all of the prediction samples of the video unit are compensated using the IBC with LIC.

[0148] Item 18. The method of Item 6, wherein the IBC with LIC is applied to at least one of: IBC Advanced Motion Vector Prediction (AMVP) mode, or IBC Merge mode.

[0149] Item 19. A method according to Item 18, wherein the IBC AMVP mode includes at least one of the following: a normal IBC AMVP mode, an IBC AMVP mode based on template matching (TM), a reconstruction-reordering IBC (RR-IBC) AMVP mode, a combined IBC and intra-frame prediction (IBC-CIIP) mode, an IBC with geometric partitioning mode (IBC-GPM) mode, or other IBC AMVP modes in which a BV prediction value is derived and a block vector difference (BVD) is indicated or derived.

[0150] Item 20. The method of Item 18, wherein the IBC Merge mode comprises at least one of: a normal IBC Merge mode, an IBC-TM Merge mode, an IBC-Merge mode with Block Vector Difference (MBVD) mode, an IBC-CIIP mode, or an IBC-GPM mode.

[0151] Clause 21. The method of clause 6, wherein the IBC with LIC is applied to an IBC Merge candidate type, or wherein the IBC with LIC is not allowed to be applied to the IBC Merge candidate type.

[0152] Item 22. The method of Item 21, wherein the IBC Merge candidate type comprises a RR-IBC candidate.

[0153] Clause 23. The method of clause 6, wherein the IBC with LIC is not allowed to be applied to at least one IBC codec.

[0154] Item 24. The method of Item 23, wherein the at least one IBC codec comprises one or more of: RR-IBC, IBC-CIIP, or IBC-GPM.

[0155] Item 25. A method according to Item 6, wherein whether the IBC with LIC is applied for at least one of the IBC AMVP mode or the IBC Merge mode and / or the method of applying the IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode is indicated, or wherein whether the IBC with LIC is applied for at least one of the IBC AMVP mode or the IBC Merge mode and / or the method of applying the IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode is determined based on the codec information of the video unit.

[0156] Item 26. A method according to Item 6, wherein at least one syntax element is indicated to indicate whether the IBC with LIC is applied for at least one of the IBC AMVP mode or the IBC Merge mode and / or the method of applying the IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode.

[0157] Item 27. The method of Item 6, wherein whether to apply the IBC with LIC for IBC Merge mode and / or the method of applying the IBC with LIC for IBC Merge mode is inherited.

[0158] Item 28. The method of Item 27, wherein whether to apply the IBC with LIC and / or inheritance of the method of applying the IBC with LIC is associated with a Merge candidate.

[0159] Item 29. The method of Item 28, wherein when the Merge candidate belongs to a target Merge type, the IBC with LIC is disabled.

[0160] Item 30. The method according to Item 29, wherein the target Merge type is RR-IBC.

[0161] Item 31. The method according to Item 6, wherein whether to apply IBC with LIC and / or the method of applying IBC with LIC depends on the codec information of the video unit.

[0162] Item 32. A method according to Item 31, wherein the encoding and decoding information of the video unit includes at least one of the following: block dimension, block size, depth of the video unit, slice type, picture type, partition tree type, block position, quantization parameter, or color component.

[0163] Item 33. The method of Item 32, wherein the IBC with LIC is applied only to I slices or I pictures.

[0164] Item 34. The method of Item 1, wherein the refinement process includes a plurality of LIC models, and the plurality of LIC models are used to compensate the prediction samples of the video unit derived using IBC.

[0165] Clause 35. The method of clause 34, wherein the plurality of LIC types comprises different LIC models having adjustment parameters for one or more existing parameters of the LIC.

[0166] Item 36. The method of Item 35, wherein the adjustment parameter is used to adjust α, wherein α is an existing parameter of the LIC.

[0167] Item 37. The method of Item 36, wherein α is adjusted to α+u or α×u, and wherein u is the adjustment parameter.

[0168] Clause 38. The method of clause 35, wherein the adjustment parameter is used to adjust β, wherein β is an existing parameter of the LIC.

[0169] Item 39. The method of Item 38, wherein β is adjusted to β+v or β×v, and wherein v is the adjustment parameter.

[0170] Item 40. The method of Item 34, wherein parameters of the plurality of LIC models are derived using different templates.

[0171] Item 41. The method according to Item 40, wherein different sample point lines of a template are used to derive the parameters of the plurality of LIC models.

[0172] Item 42. The method of Item 40, wherein at least one of the following is used to derive the parameters of the multiple LIC models: a left template, an upper template, or an upper-left template.

[0173] Item 43. The method according to Item 40, wherein samples from different positions in the template are used to derive the parameters of the multiple LIC models.

[0174] Item 44. A method according to Item 43, wherein the different positions include downsampling positions.

[0175] Item 45. The method of Item 40, wherein samples in different categories are used to derive the parameters of the plurality of LIC models.

[0176] Item 46. The method according to Item 45, wherein the different categories depend on the samples of the template to which they are classified.

[0177] Item 47. A method according to Item 45, wherein the average value of the samples in the template is used to derive the different categories.

[0178] Item 48. The method of Item 34, wherein whether to apply one of the multiple LIC models and / or a method of applying one of the multiple LIC models is indicated using a syntax element, and the syntax element is indicated in the bitstream.

[0179] Item 49. The method according to Item 34, wherein whether to apply one LIC model among the plurality of LIC models and / or a method of applying one LIC model among the plurality of LIC models is adaptively determined.

[0180] Item 50. A method according to item 1, wherein the position or shape of the template depends on the codec information of the video unit.

[0181] Item 51. A method according to Item 50, wherein if the left neighboring sample point is not available, the template only includes the upper neighboring sample points.

[0182] Item 52. The method of Item 50, wherein if an upper neighboring sample point is not available, the template includes only a left neighboring sample point.

[0183] Item 53. The method according to Item 50, wherein the IBC with LIC is not applicable if the left and upper neighboring sample points are not available.

[0184] Item 54. The method of Item 50, wherein the template comprises a template of a current block or a template of a reference block associated with the video unit.

[0185] Item 55. The method according to Item 1, wherein the position or shape of the template depends on whether RR-IBC or normal IBC is applied.

[0186] Item 56. The method of Item 1, wherein the position or shape of the template comprises one or more sample point lines.

[0187] Item 57. A method according to Item 1, wherein the position or shape of the template is predefined, or wherein the position or shape of the template is indicated, or wherein the position or shape of the template is derived on the fly.

[0188] Item 58. A method according to Item 1, wherein the position or shape of the template depends on at least one of the following: the width or height of the video unit.

[0189] Item 59. The method of Item 1, wherein the reference template is constrained in an IBC cache, or wherein the reference template is not constrained in the IBC cache.

[0190] Item 60. The method of Item 1, further comprising: determining, based on the coded information of the video unit, whether the video unit is allowed to be coded using the IBC mode with LIC.

[0191] Item 61. A method according to item 60, wherein the encoded information includes at least one of the following: block dimension, block size, depth of block, block position, slice type, picture type, temporal layer, color format, or color component.

[0192] Item 62. A method according to Item 61, wherein if the block size represented by WH is less than or equal to a threshold, the video unit is allowed to be encoded and decoded using the IBC mode with LIC, wherein W represents the block width of the video unit and H represents the block height of the video unit.

[0193] Item 63. A method according to item 62, wherein the threshold is one of the following: 256, or 512, or 1024, or 2048, or 4096.

[0194] Item 64. The method of Item 1, wherein whether to apply IBC with LIC and / or the method of applying IBC with LIC depends on at least one of: a color format or a color component.

[0195] Item 65. The method of Item 64, wherein the IBC with LIC is applied to all color components.

[0196] Item 66. The method of Item 64, wherein whether to apply the IBC with LIC to the first component and / or the method of applying the IBC with LIC to the first component depends on whether to apply the IBC with LIC to the second component.

[0197] Item 67. The method of Item 66, wherein the first component comprises a chrominance component and the second component comprises a luma component.

[0198] Item 68. The method of Item 66, wherein the method of applying the IBC with LIC to the first component is the same as the method of applying the IBC with LIC to the second component.

[0199] Item 69. The method of Item 66, wherein the method of applying the IBC with LIC to the first component is different from the method of applying the IBC with LIC to the second component.

[0200] Item 70. The method of Item 64, wherein the IBC with LIC is applied to luma components but not to chroma components.

[0201] Item 71. The method of Item 70, wherein the luminance component comprises Y in a YCbCr color space or G in an RGB color space.

[0202] Item 72. A method according to Item 70, wherein the chrominance component includes at least one of the following: Cb or Cr in the YCbCr color space, or wherein the chrominance component includes at least one of the following: R or B in the RGB color space.

[0203] Item 73. The method of Item 1, wherein the indication of the IBC mode with LIC is indicated based on a condition.

[0204] Item 74. A method according to Item 73, wherein the condition includes at least one of the following: whether the target coding method is allowed, block dimension, block size, block depth, slice type, picture type, partition tree type, temporal layer identifier, block position, or color component.

[0205] Item 75. The method of Item 74, wherein the target codec method comprises at least one of: IBC, IBC AMVP, IBC Merge, RR-IBC, IBC-CIIP, IBC-TM, or IBC-GPM.

[0206] Item 76. The method of Item 1, wherein whether the video unit is encoded or decoded using IBC mode with LIC is indicated using at least one syntax element.

[0207] Item 77. A method according to item 76, wherein the at least one syntax element is binarized using one of the following: fixed length codec, truncated unary codec, unary codec, EG codec, or a codec flag.

[0208] Item 78. A method according to item 76, wherein the at least one syntax element is bypass coded or context coded.

[0209] Item 79. The method of Item 78, wherein the context depends on encoded and decoded information of the video unit.

[0210] Item 80. A method according to Item 79, wherein the encoded information includes at least one of the following: block dimension, block size, slice type, picture type, information of neighboring blocks, information of other codec tools used for the current block, or time domain layer information.

[0211] Item 81. The method of Item 78, wherein the context depends on whether a neighboring block is encoded or decoded using the IBC mode with LIC.

[0212] Item 82. The method of Item 76, wherein if the video unit is IBC coded, the indication of the IBC mode with LIC is indicated.

[0213] Item 83. A method according to Item 76, wherein the at least one syntax element is indicated before the indication of the target codec tool, or wherein the at least one syntax element is indicated after the indication of the target codec tool.

[0214] Item 84. A method according to Item 83, wherein the target codec tool includes at least one of the following: RR-IBC mode, IBC-TM mode, IBC-MBVD mode, IBC-CIIP, or IBC-GPM.

[0215] Item 85. A method according to Item 83, wherein whether to indicate the at least one syntax element and / or the method of indicating the at least one syntax element depends on whether at least one of the following is enabled for the video unit: IBC mode, RR-IBC mode, IBC-TM mode, IBC-MBVD mode, IBC-CIIP or IBC-GPM.

[0216] Item 86. A method according to item 83, wherein the at least one syntax element is indicated after the indication of the RR-IBC mode.

[0217] Item 87. A method according to item 86, wherein if the RR-IBC mode is applied, the at least one syntax element indicating the IBC with LIC is not indicated and is set to a default value, and the default value indicates that the IBC with LIC is not applied.

[0218] Item 88. The method of Item 76, wherein the at least one syntax element is indicated if the video unit is encoded and decoded using IBC-AMVP mode.

[0219] Item 89. A method according to item 76, wherein the at least one syntax element is indicated at one of the following: a sequence header, a picture header, a sequence parameter set (SPS), a video parameter set (VPS), a dependency parameter set (DPS), decoding capability information (DCI), a picture parameter set (PPS), an adaptation parameter set (APS), a slice header, or a slice group header.

[0220] Item 90. The method of Item 76, wherein the at least one syntax element is encoded in a predictive manner.

[0221] Item 91. The method of item 76, wherein the at least one syntax element of the current block of the video unit is predicted by at least one syntax element of a neighboring block.

[0222] Item 92. A method according to any one of Items 1 to 91, wherein the video unit includes at least one of the following: a color component, a prediction block (PB), a transform block (TB), a codec block (CB), a prediction unit (PU), a transform unit (TU), a codec tree block (CTB), a codec unit (CU), a codec tree unit (CTU), a CTU row, a CTU group, a slice, a sub-picture, a block, a sub-region within a block, or a region containing more than one sample or pixel.

[0223] Item 93. A method according to any one of Items 1 to 92, wherein an indication of whether and / or how the refined prediction samples of the video unit are derived by applying a refinement process to the prediction samples is indicated at one of the following: sequence level, picture group level, picture level, slice level, or slice group level.

[0224] Item 94. A method according to any one of Items 1 to 92, wherein an indication of whether and / or how the refined prediction samples of the video unit are derived by applying a refinement process to the prediction samples is indicated in one of the following: a sequence header, a picture header, a sequence parameter set (SPS), a video parameter set (VPS), a dependency parameter set (DPS), decoding capability information (DCI), a picture parameter set (PPS), an adaptation parameter set (APS), a slice header, or a slice group header.

[0225] Item 95. A method according to any one of Items 1 to 92, wherein an indication of whether and / or how the refined prediction samples of the video unit are derived by applying a refinement process to the prediction samples is indicated at one of the following: a PB, a TB, a CB, a PU, a TU, a CU, a VPDU, a CTU, a CTU row, a slice, a slice, a sub-picture, or a region containing more than one sample or pixel.

[0226] Item 96. A method according to any one of Items 1 to 92, wherein whether the refined prediction samples of the video unit are derived by applying a refinement process to the prediction samples and / or how the refined prediction samples of the video unit are derived by applying a refinement process to the prediction samples is coded information of the video unit, and wherein the coded information includes at least one of the following: block size, color format, single tree partitioning, double tree partitioning, color component, slice type, or picture type.

[0227] Item 97. A method according to any one of Items 1 to 96, wherein the conversion includes encoding the video unit into the bitstream.

[0228] Item 98. A method according to any one of Items 1 to 96, wherein the converting comprises decoding the video unit from the bitstream.

[0229] Item 99. An apparatus for video processing, comprising a processor and a non-volatile memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform a method according to any one of Items 1 to 98.

[0230] Item 100. A non-transitory computer-readable storage medium storing instructions for causing a processor to perform a method according to any one of Items 1 to 98.

[0231] Item 101. A non-transitory computer-readable recording medium storing a bitstream of a video generated by a method performed by an apparatus for video processing, wherein the method comprises: deriving prediction samples of a video unit of the video; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; and generating the bitstream based on the refined prediction samples.

[0232] Item 102. A method for storing a bitstream of a video, comprising: deriving prediction samples of a video unit of the video; deriving refined prediction samples of the video unit by applying a refinement process to the prediction samples; generating the bitstream based on the refined prediction samples; and storing the bitstream in a non-transitory computer-readable recording medium. Example Device

[0233] Fig.18 A block diagram of a computing device 1800 in which various embodiments of the present disclosure may be implemented is shown. The computing device 1800 may be implemented as a source device 110 (or video encoder 114 or 200) or a destination device 120 (or video decoder 124 or 300), or may be included in a source device 110 (or video encoder 114 or 200) or a destination device 120 (or video decoder 124 or 300).

[0234] It should be understood that Fig.18 The computing device 1800 shown in FIG. 1 is for illustrative purposes only and is not intended to in any way imply any limitation on the functionality and scope of the embodiments of the present disclosure.

[0235] like Fig.18 As shown, computing device 1800 includes a general computing device 1800. Computing device 1800 may include at least one or more processors or processing units 1810, memory 1820, storage unit 1830, one or more communication units 1840, one or more input devices 1850, and one or more output devices 1860.

[0236] In some embodiments, computing device 1800 can be implemented as any user terminal or server terminal with computing power. The server terminal can be a server, a large computing device, etc. provided by a service provider. The user terminal can be, for example, any type of mobile terminal, fixed terminal or portable terminal, including a mobile phone, a station, a unit, a device, a multimedia computer, a multimedia tablet computer, an Internet node, a communicator, a desktop computer, a laptop computer, a notebook computer, a netbook computer, a tablet computer, a personal communication system (PCS) device, a personal navigation device, a personal digital assistant (PDA), an audio / video player, a digital camera / camcorder, a positioning device, a television receiver, a radio broadcast receiver, an electronic book device, a gaming device, or any combination thereof, including the accessories and peripherals of these devices, or any combination thereof. It is conceivable that computing device 1800 can support any type of interface to the user (such as a "wearable" circuit device, etc.).

[0237] The processing unit 1810 may be a physical processor or a virtual processor and may implement various processes based on a program stored in the memory 1820. In a multi-processor system, multiple processing units execute computer executable instructions in parallel to increase the parallel processing capability of the computing device 1800. The processing unit 1810 may also be referred to as a central processing unit (CPU), a microprocessor, a controller, or a microcontroller.

[0238] The computing device 1800 typically includes various computer storage media. Such media can be any media accessible by the computing device 1800, including but not limited to volatile media and non-volatile media, or removable media and non-removable media. The memory 1820 can be a volatile memory (e.g., a register, a cache, a random access memory (RAM)), a non-volatile memory (such as a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM) or flash memory) or any combination thereof. The storage unit 1830 can be any removable or non-removable medium, and can include machine-readable media, such as a memory, a flash drive, a disk, or other media that can be used to store information and / or data and can be accessed in the computing device 1800.

[0239] The computing device 1800 may also include additional removable / non-removable storage media, volatile / non-volatile storage media. Fig.18 Although not shown in the figure, a disk drive for reading from and / or writing to a removable nonvolatile disk and an optical drive for reading from and / or writing to a removable nonvolatile optical disk may be provided. In this case, each drive may be connected to the bus (not shown) via one or more data medium interfaces.

[0240] The communication unit 1840 communicates with another computing device via a communication medium. In addition, the functions of the components in the computing device 1800 can be implemented by a single computing cluster or multiple computing machines, which can communicate via a communication connection. Therefore, the computing device 1800 can operate in a networked environment using logical connections to one or more other servers, networked personal computers (PCs), or other general network nodes.

[0241] The input device 1850 may be one or more of various input devices, such as a mouse, keyboard, trackball, voice input device, etc. The output device 1860 may be one or more of various output devices, such as a display, a speaker, a printer, etc. With the aid of the communication unit 1840, the computing device 1800 may also communicate with one or more external devices (not shown), such as storage devices and display devices, and the computing device 1800 may also communicate with one or more devices that enable a user to interact with the computing device 1800, or, if necessary, the computing device 1800 may also communicate with any device (e.g., a network card, a modem, etc.) that enables the computing device 1800 to communicate with one or more other computing devices. Such communication may be performed via an input / output (I / O) interface (not shown).

[0242] In some embodiments, some or all components of the computing device 1800 may also be arranged in a cloud computing architecture, rather than being integrated in a single device. In a cloud computing architecture, components may be provided remotely and work together to implement the functions described in the present disclosure. In some embodiments, cloud computing provides computing, software, data access and storage services, which will not require the end user to know the physical location or configuration of the system or hardware that provides these services. In various embodiments, cloud computing provides services via a wide area network (such as the Internet) using a suitable protocol. For example, a cloud computing provider provides an application via a wide area network, which can be accessed through a web browser or any other computing component. The software or components of the cloud computing architecture and the corresponding data may be stored on a server at a remote location. The computing resources in a cloud computing environment may be merged or distributed at the location of a remote data center. Cloud computing infrastructure can provide services through a shared data center, although they appear as a single access point to the user. Therefore, the cloud computing architecture may be used to provide the components and functions described herein from a service provider at a remote location. Alternatively, the components and functions described herein may be provided by a conventional server, or may be installed directly or otherwise on a client device.

[0243] In an embodiment of the present disclosure, the computing device 1800 may be used to implement video encoding / decoding. The memory 1820 may include one or more video encoding / decoding modules 1825 having one or more program instructions. These modules are accessible and executable by the processing unit 1810 to perform the functions of the various embodiments described herein.

[0244] In an example embodiment performing video encoding, input device 1850 may receive video data as input 1870 to be encoded. The video data may be processed, for example, by video codec module 1825 to generate an encoded bitstream. The encoded bitstream may be provided as output 1880 via output device 1860.

[0245] In an example embodiment performing video decoding, input device 1850 may receive an encoded bitstream as input 1870. The encoded bitstream may be processed, for example, by video codec module 1825 to generate decoded video data. The decoded video data may be provided as output 1880 via output device 1860.

[0246] Although the present disclosure has been specifically shown and described with reference to the preferred embodiments of the present disclosure, it will be appreciated by those skilled in the art that various changes may be made in form and detail without departing from the spirit and scope of the present application as defined by the appended claims. These modifications are intended to be encompassed by the scope of the present application. Therefore, the foregoing description of the embodiments of the present application is not intended to be limiting.

Claims

1. A video processing method, include: For conversion between a video unit of a video and a bit stream of the video, deriving prediction samples of the video unit; deriving refined prediction samples for the video unit by applying a refinement process to the prediction samples; and The conversion is performed based on the refined prediction samples.

2. The method according to claim 1, wherein the refined prediction samples are derived as: f(p[x])=α×p[x]+β, Wherein f(p[x]) represents the refined prediction sample point, p[x] represents the prediction sample point, f represents the refinement process, the refinement process is a function, and α and β represent the parameters of the linear model respectively.

3. The method of claim 1 , wherein the function of the refinement process is derived based on a template of a current block associated with the video unit, or Wherein at least one parameter of the function of the refinement process is derived based on the template of the current block associated with the video unit.

4. The method of claim 1, wherein the prediction samples are derived by intra block copying (IBC).

5. The method according to claim 4, wherein the function of the refinement process or at least one parameter of the function is derived based on a template of a reference block associated with the video unit, and The reference block is located by a block vector.

6. The method of claim 1, wherein the refinement process comprises local illumination compensation (LIC), and wherein the refined prediction samples are obtained based on IBC with LIC.

7. The method according to claim 6, wherein the method include: deriving the prediction samples of the video unit by applying the IBC; as well as The refined prediction samples for the video unit are derived by applying the LIC to compensate the prediction samples for the video unit.

8. The method of claim 6, wherein a linear model is used for the IBC with LIC to compensate the prediction samples of the video unit, or A nonlinear model is used in the IBC with LIC to compensate the prediction samples of the video unit.

9. The method of claim 8, wherein the linear model is represented as: α×p[x]+β, in, p[x] represents the prediction sample of the video unit, and α and β represent parameters of the linear model respectively.

10. The method of claim 6, wherein parameters of the model used in the IBC with LIC are predefined or indicated in the bitstream.

11. The method of claim 6, wherein parameters of a model used in the IBC with LIC are derived based on codec information of the video unit.

12. The method of claim 11, wherein a current template and a reference template comprising neighboring reconstructed samples of the video unit are used to derive the parameters.

13. The method of claim 12, wherein the reference template is derived using a BV, the BV being used to obtain the prediction samples for the video unit.

14. The method according to claim 12, wherein a part or all of the samples of the reference template and the current template are used to derive the parameters.

15. The method of claim 12, wherein a least square error method is used to derive the parameters.

16. The method of claim 6, wherein a method of deriving the parameters using a current template and a reference template of the video unit is the same as LIC for inter-frame prediction.

17. The method of claim 6, wherein a portion or all of the prediction samples of the video unit are compensated using the IBC with LIC.

18. The method of claim 6, wherein the IBC with LIC is applied to at least one of the following: IBC Advanced Motion Vector Prediction (AMVP) mode, or IBC Merge mode.

19. The method of claim 18, wherein the IBCAMVP mode comprises at least one of the following: Normal IBC AMVP mode, IBC AMVP mode based on Template Matching(TM), Rebuild-Reorder IBC (RR-IBC) AMVP mode, Combined IBC and intra prediction (IBC-CIIP) mode, IBC with geometric partitioning mode (IBC-GPM) mode, or Other IBC AMVP modes where BV prediction values ​​are derived and block vector differences (BVDs) are indicated or derived.

20. The method of claim 18, wherein the IBC Merge mode comprises at least one of the following: Normal IBC Merge mode, IBC-TM Merge mode, IBC-Merge mode with Block Vector Difference (MBVD) mode, IBC-CIIP mode, or IBC-GPM model.

21. The method of claim 6, wherein the IBC with LIC is applied to an IBC Merge candidate type, or Wherein the IBC with LIC is not allowed to be applied to the IBC Merge candidate type.

22. The method of claim 21, wherein the IBC Merge candidate type comprises a RR-IBC candidate.

23. The method of claim 6, wherein the IBC with LIC is not allowed to be applied to at least one IBC codec.

24. The method of claim 23, wherein the at least one IBC codec tool comprises one or more of: RR-IBC, IBC-CIIP, or IBC-GPM.

25. The method of claim 6, wherein whether to apply the IBC with LIC for at least one of IBC AMVP mode or IBC Merge mode and / or a method of applying the IBC with LIC for at least one of IBC AMVP mode or IBC Merge mode is indicated, or A method in which whether to apply the IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode and / or applying the IBC with LIC for at least one of the IBC AMVP mode or the IBC Merge mode is determined based on the codec information of the video unit.

26. The method of claim 6, wherein at least one syntax element is indicated to indicate whether the IBC with LIC is applied for at least one of IBC AMVP mode or IBC Merge mode and / or a method of applying the IBC with LIC for at least one of IBC AMVP mode or IBC Merge mode.

27. The method of claim 6, wherein whether to apply the IBC with LIC for an IBC Merge mode and / or a method of applying the IBC with LIC for an IBC Merge mode is inherited.

28. The method of claim 27, wherein whether to apply the IBC with LIC and / or the inheritance of the method of applying the IBC with LIC is associated with a Merge candidate.

29. The method of claim 28, wherein when a merge candidate belongs to a target merge type, the IBC with LIC is disabled.

30. The method of claim 29, wherein the target Merge type is RR-IBC.

31. The method of claim 6, wherein whether to apply IBC with LIC and / or a method of applying IBC with LIC depends on codec information of the video unit.

32. The method of claim 31 , wherein the codec information of the video unit comprises at least one of the following: Block dimensions, Block size, the depth of the video unit, Strip type, Image type, Split tree type, Block location, quantization parameter, or Color component.

33. The method of claim 32, wherein the IBC with LIC is applied only to I slices or I pictures.

34. The method of claim 1, wherein the refinement process includes a plurality of LIC models, and the plurality of LIC models are used to compensate the prediction samples of the video unit derived using IBC.

35. The method of claim 34, wherein the plurality of LIC types comprises different LIC models having adjustment parameters for one or more existing parameters of the LIC.

36. The method of claim 35, wherein the adjustment parameter is used to adjust α, which is an existing parameter of the LIC.

37. The method of claim 36, wherein α is adjusted to α+u or α×u, and wherein u is the adjustment parameter.

38. The method of claim 35, wherein the adjustment parameter is used to adjust β, which is an existing parameter of the LIC.

39. The method of claim 38, wherein β is adjusted to β+v or β×v, and wherein v is the adjustment parameter.

40. The method of claim 34, wherein parameters of the plurality of LiC models are derived using different templates.

41. The method of claim 40, wherein different sample point lines of a template are used to derive the parameters of the plurality of LiC models.

42. The method of claim 40, wherein at least one of the following is used to derive the parameters of the plurality of LiC models: Left template, The template above, or Top left template.

43. The method of claim 40, wherein samples from different locations in a template are used to derive the parameters of the plurality of LIC models.

44. The method of claim 43, wherein the different locations comprise downsampled locations.

45. The method of claim 40, wherein samples in different categories are used to derive the parameters of the plurality of LIC models.

46. ​​The method of claim 45, wherein the different categories depend on the template into which the samples are classified.

47. The method of claim 45, wherein an average value of samples in a template is used to derive the different classes.

48. The method according to claim 34, wherein whether to apply one LIC model among the plurality of LIC models and / or a method of applying one LIC model among the plurality of LIC models is indicated using a syntax element, and the syntax element is indicated in the bitstream.

49. The method of claim 34, wherein whether to apply one LIC model among the plurality of LIC models and / or a method of applying one LIC model among the plurality of LIC models is adaptively determined.

50. The method of claim 1, wherein a position or shape of the template depends on codec information of the video unit.

51. The method of claim 50, wherein if a left neighboring point is not available, the template includes only an upper neighboring point.

52. The method of claim 50, wherein if an upper neighboring point is not available, the template includes only a left neighboring point.

53. The method of claim 50, wherein the IBC with LIC is not applicable if the left and upper neighboring sample points are not available.

54. The method of claim 50, wherein the template comprises a template of a current block or a template of a reference block associated with the video unit.

55. The method of claim 1, wherein the position or shape of the template depends on whether a RR-IBC or a normal IBC is applied.

56. The method of claim 1, wherein the location or shape of the template comprises one or more point-like lines.

57. The method of claim 1, wherein the position or shape of the template is predefined, or wherein the position or the shape of the template is indicated, or The position or the shape of the template is derived instantly.

58. The method of claim 1, wherein a position or shape of a template depends on at least one of: a width or a height of the video unit.

59. The method of claim 1, wherein the reference template is constrained in an IBC cache, or The reference template is not constrained in the IBC cache.

60. The method according to claim 1, further comprising: include: Based on the coded information of the video unit, it is determined whether the video unit is allowed to be coded using the IBC mode with LIC.

61. The method of claim 60, wherein the encoded information comprises at least one of: Block dimensions, Block size, The depth of the block, Block location, Strip type, Image type, Time domain layer, color format, or Color component.

62. The method of claim 61, wherein the video unit is allowed to be encoded and decoded using the IBC mode with LIC if the block size represented as W×H is less than or equal to a threshold, wherein W represents a block width of the video unit and H represents a block height of the video unit.

63. A method according to claim 62, wherein the threshold is one of the following: 256, or 512, or 1024, or 2048, or 4096.

64. The method of claim 1, wherein whether to apply IBC with LIC and / or the method of applying IBC with LIC depends on at least one of: color format or color component.

65. The method of claim 64, wherein the IBC with LIC is applied to all color components.

66. The method of claim 64, wherein whether to apply the IBC with LIC to a first component and / or a method of applying the IBC with LIC to a first component depends on whether to apply the IBC with LIC to a second component.

67. The method of claim 66, wherein the first component comprises a chrominance component and the second component comprises a luma component.

68. The method of claim 66, wherein the method of applying the IBC with LIC to the first component is the same as the method of applying the IBC with LIC to the second component.

69. The method of claim 66, wherein the method of applying the IBC with LIC to the first component is different from the method of applying the IBC with LIC to the second component.

70. The method of claim 64, wherein the IBC with LIC is applied to luma components but not to chroma components.

71. The method of claim 70, wherein the luma component comprises Y in a YCbCr color space or G in an RGB color space.

72. The method of claim 70, wherein the chrominance component comprises at least one of: Cb or Cr in a YCbCr color space, or The chrominance component includes at least one of the following: R or B in the RGB color space.

73. The method of claim 1, wherein the indication of the IBC mode with LIC is indicated based on a condition.

74. The method of claim 73, wherein the condition comprises at least one of: Whether the target codec method is allowed, Block dimensions, Block size, Block depth, Strip type, Image type, Split tree type, Time domain layer identification, block location, or Color component.

75. The method of claim 74, wherein the target encoding and decoding method comprises at least one of the following: IBC, IBC AMVP, IBC Merge, RR-IBC, IBC-CIIP, IBC-TM, or IBC-GPM.

76. The method of claim 1, wherein whether the video unit is encoded or decoded utilizing IBC mode with LIC is indicated using at least one syntax element.

77. The method of claim 76, wherein the at least one syntax element is binarized using one of: a fixed length codec, a truncated unary codec, a unary codec, an EG codec, or a codec flag.

78. The method of claim 76, wherein the at least one syntax element is bypass coded or context coded.

79. The method of claim 78, wherein the context depends on encoded information of the video unit.

80. The method of claim 79, wherein the encoded information includes at least one of: Block dimensions, Block size, Strip type, Image type, Information about neighboring blocks, Information about other codecs for the current block, or Time domain layer information.

81. The method of claim 78, wherein the context depends on whether a neighboring block is encoded or decoded using the IBC mode with LIC.

82. The method of claim 76, wherein if the video unit is IBC coded, the indication of IBC mode with LIC is indicated.

83. The method of claim 76, wherein the at least one syntax element is indicated prior to the indication of the target codec, or The at least one syntax element is indicated after the indication of the target codec tool.

84. The method of claim 83, wherein the target codec tool comprises at least one of: RR-IBC mode, IBC-TM mode, IBC-MBVD mode, IBC-CIIP, or IBC-GPM.

85. A method according to claim 83, wherein whether to indicate the at least one syntax element and / or the method of indicating the at least one syntax element depends on whether at least one of the following is enabled for the video unit: IBC mode, RR-IBC mode, IBC-TM mode, IBC-MBVD mode, IBC-CIIP or IBC-GPM.

86. The method of claim 83, wherein the at least one syntax element is indicated after an indication of a RR-IBC mode.

87. The method of claim 86, wherein if the RR-IBC mode is applied, the at least one syntax element indicating the IBC with LIC is not indicated and is set to a default value, the default value indicating that the IBC with LIC is not applied.

88. The method of claim 76, wherein the at least one syntax element is indicated if the video unit is encoded and decoded using an IBC-AMVP mode.

89. The method of claim 76, wherein the at least one syntax element is indicated at one of: Sequence header, Picture header, Sequence Parameter Set (SPS), Video Parameter Set (VPS), Dependent Parameter Set (DPS), Decoding Capability Information (DCI), Picture Parameter Set (PPS), Adaptive Parameter Set (APS), Strip header, or Film group header.

90. The method of claim 76, wherein the at least one syntax element is encoded in a predictive manner.

91. The method of claim 76, wherein the at least one syntax element of a current block of the video unit is predicted by at least one syntax element of a neighboring block.

92. The method of any one of claims 1 to 91, wherein the video unit comprises at least one of: Color component, Prediction Block (PB), Transform Block (TB), Codec Block (CB), Prediction Unit (PU), Transformation Unit (TU), Codec Tree Block (CTB), Codec Unit (CU), Codec Tree Unit (CTU), CTU line, CTU group, Strips, piece, Sub-picture, piece, a sub-region within a block, or An area containing more than one sample or pixel.

93. The method of any one of claims 1 to 92, wherein an indication of whether and / or how to derive refined prediction samples for the video unit by applying a refinement process to the prediction samples is indicated at one of: Sequence level, Picture group level, Picture level, Stripe level, or Film group level.

94. The method of any one of claims 1 to 92, wherein an indication of whether and / or how the refined prediction samples for the video unit are derived by applying a refinement process to the prediction samples is indicated in one of: Sequence header, Picture header, Sequence Parameter Set (SPS), Video Parameter Set (VPS), Dependent Parameter Set (DPS), Decoding Capability Information (DCI), Picture Parameter Set (PPS), Adaptive Parameter Set (APS), Strip header, or Film group header.

95. The method of any one of claims 1 to 92, wherein an indication of whether and / or how to derive refined prediction samples for the video unit by applying a refinement process to the prediction samples is indicated at one of: PB, TB, CB, PU, TU, CU, VPDU, CTU, CTU line, Strips, piece, sub-image, or An area containing more than one sample or pixel.

96. The method according to any one of claims 1 to 92, wherein whether and / or how the refined prediction samples of the video unit are derived by applying a refinement process to the prediction samples is coded information of the video unit, and The encoded and decoded information includes at least one of the following: Block size, Color format, Single tree partitioning, Dual tree partitioning, Color component, Strip type, or Image type.

97. The method of any one of claims 1 to 96, wherein the converting comprises encoding the video unit into the bitstream.

98. The method of any one of claims 1 to 96, wherein the converting comprises decoding the video unit from the bitstream.

99. An apparatus for video processing, comprising a processor and a non-volatile memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform a method according to any one of claims 1 to 98.

100. A non-transitory computer readable storage medium storing instructions for causing a processor to perform a method according to any one of claims 1 to 98.

101. A non-transitory computer-readable recording medium storing a bit stream of a video generated by a method performed by an apparatus for video processing, wherein the method include: deriving predicted samples of a video unit of the video; deriving refined prediction samples for the video unit by applying a refinement process to the prediction samples; as well as The bitstream is generated based on the refined prediction samples.

102. A method for storing a bit stream of a video, include: deriving predicted samples of a video unit of the video; deriving refined prediction samples for the video unit by applying a refinement process to the prediction samples; generating the bitstream based on the refined prediction samples; as well as The bit stream is stored in a non-transitory computer-readable recording medium.

Images