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 includes determining whether to apply Intra Block Copy (IBC) and Local Lighting Compensation (LIC) (IBC-LIC) modes to a video unit for a conversion between the video unit of a video and a bitstream of the video unit; if it is determined that the IBC-LIC mode is applied to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, where deriving the refined prediction of the video unit comprises: obtaining a prediction of the video unit by applying the IBC to the video unit; and obtaining a refined prediction of the video unit by applying the LIC to the prediction; and performing a conversion based on the refined prediction sample points.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to video processing technologies, and more particularly, to intra block copy with local illumination compensation. 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-T H.263, ITU-T H.264 / MPEG-4 Part 10 Advanced Video Coding (AVC), ITU-T H.265 High Efficiency Video Coding (HEVC) standard, Versatile Video Coding (VVC) standard. However, there is an overall expectation to further improve the encoding / decoding efficiency of video encoding / 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: determining whether to apply an intra block copy (IBC) and local illumination compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of a video and a bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, where deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying IBC to the video unit; and obtaining the refined prediction of the video unit by applying LIC to the prediction; and performing the conversion based on the refined prediction samples. In this way, the encoding / decoding efficiency can be improved.

[0005] In a second aspect, an apparatus for video processing is proposed. The apparatus includes a processor and a non-transitory memory having instructions thereon. The instructions, when executed by the processor, cause the processor to execute the method according to the first aspect of the present disclosure.

[0006] In a third aspect, a non-transitory computer-readable storage medium is proposed. The non-transitory computer-readable storage medium stores instructions that cause 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 storage medium is proposed. The non-transitory computer-readable storage medium stores a bitstream generated by a method executed by an apparatus for video processing for a video. The method includes: determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, where deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying IBC to the video unit; and obtaining the refined prediction of the video unit by applying LIC to the prediction; and generating a bitstream based on the refined prediction.

[0008] In a fifth aspect, a method for storing a bitstream of a video is proposed. The method includes: determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, where deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying IBC to the video unit; and obtaining the refined prediction of the video unit by applying LIC to the prediction; generating a bitstream based on the refined prediction; and storing the bitstream in a non-transitory computer-readable recording medium.

[0009] The present invention content is provided to introduce a selection of concepts further described below in the detailed implementation in a simplified form. The present invention content is not intended to identify the 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 example embodiments of the present disclosure will become more apparent through the following detailed description with reference to the accompanying drawings. In the example embodiments of the present disclosure, the same reference numerals generally refer to the same components.

[0011] Figure 1 A block diagram showing an example video codec system according to some embodiments of the present disclosure is shown;

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

[0013] Figure 3A block diagram showing 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] Figure 6A And Figure 6B Reference sample points for wide-angle intra prediction are shown;

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

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

[0019] Figure 9A And Figure 9B MMVD search points are shown;

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

[0021] Figure 11 No subsampling for the short side is shown;

[0022] Figure 12 The IBC reference region depending on the current CU position is shown;

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

[0024] Figure 14A An illustration of BV adjustment for horizontal flipping is shown;

[0025] Figure 14B An illustration of BV adjustment for vertical flipping is shown;

[0026] Figure 15 The intra-template matching search region used is shown;

[0027] Figure 16 A template for deriving parameters for LIC for IBC is shown;

[0028] Figure 17 Sample points for deriving IBC-LIC parameters for the template are shown;

[0029] Figure 18 The adjusted reference template when RR-IBC is horizontal flipping is shown;

[0030] Figure 19 Shows an adjusted reference template when the RR-IBC is vertically flipped;

[0031] Figure 20 Shows a flowchart of a method for video processing according to an embodiment of the present disclosure; and

[0032] Figure 21 Shows a block diagram of a computing device in which various embodiments of the present disclosure can be implemented.

[0033] Throughout all the figures, the same or similar reference numerals generally refer to the same or similar elements. Detailed Description

[0034] The principles of the present disclosure will now be described with reference to some embodiments. It should be understood that the description of these embodiments is for illustrative purposes only and to assist those skilled in the art in understanding and implementing the present disclosure, and does not imply any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various ways other than those described below.

[0035] In the following description and claims, unless otherwise defined, 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 pertains.

[0036] References to "an embodiment", "embodiment", "example embodiment", etc. in the present disclosure indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include that particular feature, structure, or characteristic. Moreover, these phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is contended that such feature, structure, or characteristic, whether or not explicitly described, is within the knowledge of those skilled in the art in relation to other embodiments.

[0037] It should be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. 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 example embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0038] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the example embodiments. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprises", "comprising", "has", "having", "includes" and / or "including" when used herein specify the presence of the stated features, elements and / or components, etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. Example environment

[0039] Figure 1 is a block diagram showing an example video codec system 100 that can utilize the techniques of the present disclosure. As shown, the video codec system 100 can 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 can be configured to generate encoded video data, and the destination device 120 can be configured to decode the encoded video data generated by the source device 110. The source device 110 can include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0040] The video source 112 can include sources such as video capture devices. Examples of video capture devices 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 combinations thereof.

[0041] The video data can include one or more pictures. The video encoder 114 encodes the video data from the video source 112 to generate a bitstream. The bitstream can include a sequence of bits that form an encoded representation of the video data. The bitstream can include encoded pictures and associated data. An encoded picture is an encoded representation of a picture. The associated data can include sequence parameter sets, picture parameter sets, and other syntax structures. The I / O interface 116 can include a modulator / demodulator and / or a transmitter. The encoded video data can be directly transmitted to the destination device 120 via the I / O interface 116 through the network 130A. The encoded video data can also be stored on a storage medium / server 130B for access by the destination device 120.

[0042] 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 a source device 110 or a 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 a user. The display device 122 may be integrated with the destination device 120 or may be external to the destination device 120, which is configured to interface with an external display device.

[0043] The video encoder 114 and the video decoder 124 may operate according to video compression standards (such as the High Efficiency Video Coding (HEVC) standard, the Versatile Video Coding (VVC) standard, and other existing and / or future standards).

[0044] Figure 2 is a block diagram showing an example of a video encoder 200 according to some embodiments of the present disclosure. The video encoder 200 may be Figure 1 an example of the video encoder 114 in the system 100 shown.

[0045] The video encoder 200 may be configured to implement any or all of the techniques of the present disclosure. In Figure 2 an example, the video encoder 200 includes a plurality of functional components. The techniques described in the present disclosure may be shared among the various components of the video encoder 200. In some examples, a processor may be configured to execute any or all of the techniques described in the present disclosure.

[0046] In some embodiments, the video encoder 200 may include a splitting 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 buffer 213, and an entropy encoding unit 214. The prediction unit 202 may include a mode selection unit 203, a motion estimation unit 204, a motion compensation unit 205, and an intra prediction unit 206.

[0047] 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 the picture in which the current video block is located.

[0048] Furthermore, although some components (such as the motion estimation unit 204 and the motion compensation unit 205) may be integrated, for purposes of explanation, these components are Figure 2is shown separately in the example of

[0049] The splitting unit 201 can split the picture into one or more video blocks. The video encoder 200 and the video decoder 300 can support various video block sizes.

[0050] The mode selection unit 203 can select, for example, one coding mode among multiple coding modes (intra coding or inter coding) based on an error result, and provide the resulting intra-coded block or inter-coded block to the residual generation unit 207 to generate residual block data, and provide it to the reconstruction unit 212 to reconstruct the coded block to be used as a reference picture. In some examples, the mode selection unit 203 can select the combined intra-inter prediction (CIIP) mode, in which the prediction is based on an inter prediction signal and an intra prediction signal. In the case of inter prediction, the mode selection unit 203 can also select a resolution for the motion vector for the block (e.g., sub-pixel accuracy or integer pixel accuracy).

[0051] To perform inter prediction on the current video block, the motion estimation unit 204 can generate motion information for the current video block by comparing one or more reference frames from the cache 213 with the current video block. The motion compensation unit 205 can determine a predicted video block for the current video block based on the motion information and the decoded samples of a picture from the cache 213 other than the picture associated with the current video block.

[0052] The motion estimation unit 204 and the motion compensation unit 205 can perform different operations on the current video block, e.g., 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" can refer to a part of a picture composed of macroblocks, all of which are based on macroblocks within the same picture. Additionally, as used herein, in some aspects, a "P slice" and a "B slice" can refer to parts of a picture composed of macroblocks independent of the macroblocks in the same picture.

[0053] In some examples, the motion estimation unit 204 can perform uni-directional prediction on the current video block, and the motion estimation unit 204 can search the reference pictures in list 0 or list 1 to find a reference video block for the current video block. The motion estimation unit 204 can then generate a reference index and a motion vector, the reference index indicating the reference picture in list 0 or list 1 that contains 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 can 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 can 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.

[0054] 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 indices and a plurality of motion vectors, the plurality of reference indices indicating the plurality of reference pictures in list 0 and list 1 that contain the plurality of reference video blocks, and the plurality of motion vectors indicating the 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 indices 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.

[0055] In some examples, the motion estimation unit 204 may output a complete set of motion information for use in the decoding process of the decoder. Alternatively, in some embodiments, the motion estimation unit 204 may signal the motion information of the current video block by referring to the motion information of another video block. For example, the motion estimation unit 204 may determine that the motion information of the current video block is similar enough to the motion information of a neighboring video block.

[0056] In one example, the motion estimation unit 204 may indicate a value in the syntax structure associated with the current video block, the value indicating to the video decoder 300 that the current video block has the same motion information as another video block.

[0057] In another example, the motion estimation unit 204 may identify another video block and a motion vector difference (MVD) in the 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.

[0058] As discussed above, the video encoder 200 may signal motion vectors in a predictive manner. Two examples of predictive signaling techniques that may be implemented by the video encoder 200 include advanced motion vector prediction (AMVP) and Merge mode signaling.

[0059] 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 the decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a predicted video block and various syntax elements.

[0060] The residual generation unit 207 can generate residual data for a current video block by subtracting (e.g., indicated by a minus sign) the (multiple) predicted video blocks of the current video block from the current video block. The residual data of the current video block can include residual video blocks corresponding to different sample components of the samples in the current video block.

[0061] In other examples, such as in the skip mode, there may be no residual data for the current video block, and the residual generation unit 207 may not perform the subtraction operation.

[0062] The transform processing unit 208 can generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to the residual video block associated with the current video block.

[0063] After the transform processing unit 208 generates the transform coefficient video block associated with the current video block, the quantization unit 209 can 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.

[0064] The inverse quantization unit 210 and the inverse transform unit 211 can respectively apply inverse quantization and inverse transform to the transform coefficient video block to reconstruct the residual video block from the transform coefficient video block. The reconstruction unit 212 can add the reconstructed residual video block to the corresponding samples of one or more predicted 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.

[0065] After the reconstruction unit 212 reconstructs the video block, a loop filtering operation can be performed to reduce block effect artifacts in the video block.

[0066] The entropy coding unit 214 can receive data from other functional components of the video encoder 200. When the entropy coding unit 214 receives the data, the entropy coding unit 214 can perform one or more entropy coding operations to generate entropy-coded data and output a bitstream including the entropy-coded data.

[0067] Figure 3 is a block diagram showing an example of a video decoder 300 according to some embodiments of the present disclosure. The video decoder 300 can be Figure 1 an example of the video decoder 124 in the system 100 shown.

[0068] The video decoder 300 can be configured to perform any or all of the techniques of the present disclosure. In Figure 3In an example, video decoder 300 includes multiple functional components. The techniques described in this disclosure may be shared among the various components of video decoder 300. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

[0069] In Figure 3 an example, video decoder 300 includes entropy decoding unit 301, motion compensation unit 302, intra prediction unit 303, inverse quantization unit 304, inverse transform unit 305, and reconstruction unit 306 and buffer 307. In some examples, video decoder 300 may perform a decoding process generally opposite to the encoding process described with respect to video encoder 200.

[0070] Entropy decoding unit 301 may retrieve the encoded bitstream. The encoded bitstream may include entropy-coded video data (e.g., encoded blocks of video data). Entropy decoding unit 301 may decode the entropy-coded video data, and motion compensation unit 302 may determine motion information from the entropy-decoded video data, the motion information including motion vectors, motion vector precision, reference picture list index, and other motion information. Motion compensation unit 302 may determine such information, for example, by performing AMVP and Merge mode. AMVP is used, including deriving several most likely candidates based on data from adjacent PBs and reference pictures. Motion information generally includes horizontal motion vector displacement values and vertical motion vector displacement values, one or two reference picture indices, and in the case of a prediction region in a B slice, also an indication 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 spatially adjacent blocks or temporally adjacent blocks.

[0071] Motion compensation unit 302 may produce motion-compensated blocks, possibly performing interpolation based on an interpolation filter. An identifier for the interpolation filter used at sub-pixel precision may be included in the syntax element.

[0072] Motion compensation unit 302 may use the interpolation filter used by video encoder 200 during the encoding of a video block to calculate interpolated values for sub-integer pixels of a reference block. Motion compensation unit 302 may determine the interpolation filter used by video encoder 200 according to received syntax information, and motion compensation unit 302 may use the interpolation filter to produce a prediction block.

[0073] The motion compensation unit 302 may use at least part of the syntax information to determine the size of the blocks for encoding the (multiple) frames and / or (multiple) slices of the encoded video sequence, the partitioning information describing how each macroblock of the pictures of the encoded video sequence is partitioned, the mode indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter-frame encoded 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 encoding / decoding, signal prediction, and residual signal reconstruction. A slice may be the entire picture or may also be a region of the picture.

[0074] The intra prediction unit 303 may use, for example, the intra prediction mode received in the bitstream to form a prediction block from spatially adjacent 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.

[0075] 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 needed, a deblocking filter may also be applied to filter the decoded block to remove blocking artifact. The decoded video block is then stored in the buffer 307, which provides reference blocks for subsequent motion compensation / intra prediction, and the buffer 307 also produces the decoded video for presentation on a display device.

[0076] Some exemplary embodiments of the present disclosure will be described in detail below. It should be noted that the use of section headings in this document is for ease of understanding and does not limit the embodiments disclosed in the section to that section. Further, although some embodiments are described with reference to multi-functional video coding or other specific video codecs, the disclosed techniques are also applicable to other video coding techniques. Further, although some embodiments describe the video encoding steps in detail, it should be understood that the corresponding decoding steps of decoding will be implemented by a decoder. Further, 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 bitrates. 1. Brief Overview The present disclosure relates to video coding and decoding technologies. Specifically, the present disclosure relates to Intra Block Copy (IBC), how and / or whether to combine IBC with local illumination compensation, and other coding and decoding tools in image / video coding and decoding. The present disclosure can be applied to existing video coding and decoding standards such as HEVC or Versatile Video Coding (VVC). The present disclosure is also applicable to future video coding and decoding standards or video codecs. 2. Introduction Video coding and decoding standards have mainly evolved through the well-known ITU-T and ISO / IEC standards. ITU-T developed H.261 and H.263, and ISO / IEC developed MPEG-1 and MPEG-4 Visual. The two organizations jointly produced H.262 / MPEG-2 Video, H.264 / MPEG-4 Advanced Video Coding (AVC), and H.265 / HEVC standards. Since H.262, video coding and decoding standards have been based on a hybrid video coding and decoding structure, in which temporal prediction plus transform coding is utilized. To explore future video coding and decoding technologies beyond HEVC, VCEG and MPEG jointly established the Joint Video Exploration Team (JVET) in 2015. Since then, JVET has adopted many new methods and incorporated them into a reference software called the Joint Exploration Model (JEM). In April 2018, the Joint Video Exploration Team (JVET) between VCEG (Q6 / 16) and ISO / IEC JTC1 SC29 / WG11 (MPEG) was created to work on the VVC standard, with the goal of reducing the bit rate by 50% compared to HEVC. 2.1 Coding and Decoding Processes of Typical Video Codecs Figure 4 An example of the encoder block diagram of VVC is shown, which includes three loop filter blocks: Deblocking Filter (DF), Sample Adaptive Offset (SAO), and ALF. Different from DF that uses predefined filters, SAO and ALF utilize the original samples of the current picture to reduce the mean square error between the original samples and the reconstructed samples by adding offsets and applying Finite Impulse Response (FIR) filters respectively, where the coding and decoding side information is signaled by the offsets and filter coefficients. ALF is located in the last processing stage of each picture and can be regarded as a tool for attempting to capture and repair artifacts generated in the previous stage. 2.2 Intra Mode Coding and Decoding with 67 Intra Prediction Modes Figure 5 Sixty-seven intra prediction modes are shown. To capture any edge direction presented in natural videos, the number of directional intra modes is extended from 33 used in HEVC to 65, as Figure 5As shown, the planar mode and the DC mode remain unchanged. These dense directional intra prediction modes are applicable to all block sizes and to both luma and chroma intra prediction. In HEVC, each intra-coded block has a square shape and the length of each side is a power of 2. Therefore, no division operation is required to generate an intra prediction value using the DC mode. In VVC, a block can have a rectangular shape, which generally requires a division operation for each block. To avoid the division operation for DC prediction, only the longer side is used to calculate the average value of a non-square block. 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 further depends on the block shape. The traditional angular intra prediction directions are defined as from 45 degrees to -135 degrees in the clockwise direction. In VVC, several traditional angular intra prediction modes are adaptively replaced with wide-angle intra prediction modes for non-square blocks. The original mode index is used to signal the replaced mode, and the original mode index 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 coding / decoding method remains unchanged. Figure 6A and Figure 6B show the reference samples for wide-angle intra prediction. To support these prediction directions, an upper reference of length 2W + 1 and a left reference of length 2H + 1 are defined, as Figure 6A and Figure 6B shown. Figure 6A and Figure 6B show the reference samples for wide-angle intra prediction. The number of modes replaced in the wide-angle 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 modes As Figure 7As shown, in the case of wide-angle frame prediction, two vertical 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 brought by 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, which are [-14, -12, -10, -6, 72, 76, 78, 80]. When predicting a block through these modes, the samples in the reference buffer 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 the non-fractional modes in the traditional prediction mode and the wide-angle mode. In VVC, 4:2:2 and 4:4:4 chroma formats as well as 4:2:0 chroma format are supported. The chroma derivation mode (DM) derivation table for the 4:2:2 chroma format was initially ported from HEVC, and the number of entries was extended from 35 to 67 to align with the extension of the intra prediction mode. Since the HEVC specification does not support prediction angles below -135 degrees and above 45 degrees, the luma intra prediction modes with ranges 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 in the mapping table to more accurately transform the prediction angles of chroma blocks. 2.3 Inter-frame prediction For each inter-frame prediction CU, the motion parameters include the motion vector, the reference picture index and the reference picture list usage index, as well as additional information required for the new coding features of VVC that will be used for inter-frame prediction sample generation. The motion parameters can be signaled in an explicit or implicit manner. When encoding a CU in skip mode, the CU is associated with a PU and has no significant residual coefficients, no coded-decoded motion vector difference (delta) or reference picture index. A Merge mode is specified, whereby the motion parameters of the current CU, including spatial candidates and temporal candidates, as well as additional scheduling introduced in VVC, are obtained from neighboring CUs. The Merge mode can be applied to any inter-frame prediction CU, not just the skip mode. An alternative to the Merge mode is the explicit transmission of motion parameters, where the motion vector, the corresponding reference picture index for each reference picture list and the reference picture list usage flag, as well as other required information, are signaled explicitly for each CU. 2.4 Intra-block copy (IBC) Intra Block Copy (IBC) is a tool adopted in the HEVC extension on SCC. As is well known, it significantly improves the coding efficiency of screen content materials. Since the IBC mode is implemented as 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 displacement from the current block to the reference block that has been reconstructed within the current picture. The luminance block vectors of the CUs coded by IBC have integer precision. The chrominance block vectors are also rounded to integer precision. When used in combination with AMVR, the IBC mode can switch between 1-pixel and 4-pixel motion vector precisions. The CUs coded by IBC are regarded as a third prediction mode in addition to the intra or inter prediction modes. The IBC mode is applicable to CUs with both width and height less than or equal to 64 luma samples. On the encoder side, hash-based motion estimation is performed for IBC. The encoder performs RD checks on blocks with width or height not greater than 16 luma samples. For non-Merge modes, a block vector search is first performed using hash-based search. If the hash search does not return a valid candidate, a block-matching based local search will be performed. In the hash-based search, the hash key matching (32-bit CRC) between the current block and the reference block is extended to all allowed block sizes. The hash key calculation for each position in the current picture is based on 4×4 sub-blocks. For a current block with a larger size, the hash key is determined to match the hash key of the reference block when the hash keys of all 4×4 sub-blocks match the hash keys in 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 costs of each matching reference are calculated, and the one with the minimum cost is selected. In the block-matching search, the search range is set to cover the previous CTU and the current CTU. At the CU level, the IBC mode uses flags to signal that it can be signaled as the IBC AMVP mode or the IBC skip / Merge mode, as follows: - IBC skip / Merge mode: The Merge candidate index is used to indicate which block vector from the list of neighboring candidate IBC-coded blocks is used to predict the current block. The Merge list includes spatial candidates, HMVP candidates, and paired candidates. - IBC AMVP mode: The block vector difference is coded in the same way as the motion vector difference. The block vector prediction method uses two candidates as prediction values, one from the left neighbor and one from the upper neighbor (if it is IBC-coded). When either neighbor is not available, the default block vector is used as the prediction value. A flag is signaled to indicate the block vector prediction value index. 2.5 Merge Mode with MVD (MMVD) In addition to the Merge mode, in the case where the implicitly derived motion information is directly used for the prediction sample generation of the current CU, a Merge mode with motion vector difference (MMVD) is introduced in VVC. The MMVD flag is signaled immediately after the regular Merge flag to specify whether the MMVD mode is used for the CU. In MMVD, after a Merge candidate is selected, it is further refined by the signaled MVD information. The further information includes a Merge candidate flag, an index for specifying the motion amplitude, and an index for indicating the motion direction. In the 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 signaled to specify which one is used between the first Merge candidate and the second Merge candidate. Figure 8 A diagram showing the motion vector scaling for the temporal Merge candidates is presented. Figure 9A And Figure 9B shows. An example of the MMVD search points. The distance index specifies the motion amplitude information and indicates a predefined offset from the starting point. As Figure 9A and Figure 9B shown, the offset is added to the horizontal or 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 the distance index and the predefined offset The direction index represents the direction of the MVD relative to the starting point. The direction index can represent four directions as shown in Table 3. It should be noted that the meaning of the MVD sign can vary according to the information of the starting MV. When the starting MV is a non-predicted MV or a bi-predicted MV where both lists point to the same side of the current picture (i.e., the POCs of both references are greater than the POC of the current picture, or both are less than the POC of the current picture), the signs in Table 3 specify the signs of the MV offsets added to the starting MV. When the starting MV is a bi-predicted MV with two MVs 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 POC difference in list 0 is greater than the POC difference in list 1, the signs in Table 3 specify the signs of the MV offsets added to the list 0 MV component of the starting MV, and the sign of the list 1 MV has the opposite value. Otherwise, if the POC difference in list 1 is greater than the POC difference in list 0, then the signs in Table 3 specify the signs of the MV offsets added to the list 1 MV component of the starting MV, and the sign of the list 0 MV has the opposite value. The MVD is scaled according to the difference of POCs in each direction. If the POC differences in the two lists are the same, no scaling is required. Otherwise, if the POC difference in list 0 is greater than the POC difference in list 1, then as described in Figure 8 , the MVD of list 1 is scaled by defining the POC difference of L0 as td and the POC difference of L1 as tb. If the POC difference of L1 is greater than the POC difference of L0, then the MVD of list 0 is scaled in the same way. If the starting MV is unidirectionally predicted, then the MVD is added to the available MV. Table 3 Signs of MV offsets specified by direction indices Direction IDX 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 an encoding / decoding tool used to address the problem of local illumination changes between the current picture and its temporal reference picture. LIC is based on a linear model, where a scaling factor and an offset are applied to the reference samples to obtain the predicted samples of 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 predicted signal of the current block at coordinates (x,y); P r (x + v x , y + v y ) is the reference block pointed to by the motion vector (v x , v y ); α and β are the corresponding scaling factor and offset applied to the reference block. Figure 10 Shows the LIC process. Figure 10 Shows an example of local illumination compensation. In Figure 10 , when LIC is applied to a block, the Least Mean Square Error (LMSE) method is adopted to derive the values of the LIC parameters (i.e., α and β) by minimizing the difference between the neighboring samples of the current block (i.e., the template T in Figure 10 ) and their corresponding reference samples in the temporal reference picture (i.e., T0 or T1 in Figure 10 ). Additionally, 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 the shaded samples in Figure 10 are used to derive α and β. Figure 11 Shows no subsampling of the short side. To improve the encoding / decoding performance, as shown in Figure 11 , no subsampling of the short side is performed. 2.7 IBC with Template Matching It is proposed to also use template matching with IBC for both the IBC Merge mode and the IBC AMVP mode. Compared with the Merge list used by the conventional IBC Merge mode, the IBC-TM Merge list has been modified such that, as in the conventional TM Merge mode, candidates are selected according to a deduplication method with the motion distance between candidates. The ended zero motion completion (which is meaningless for intra coding) has been replaced by motion vectors to the left (-W, 0) CU, top (0, -H) CU, and top left (-W, -H) CU, and then, if necessary, the left CU completion list is utilized without deduplication. In the IBC-TM Merge mode, the selected candidates are refined using a template matching method before the RDO or decoding process. The IBC-TM Merge mode has competed with the conventional IBC Merge mode and signals a TM Merge flag. In the IBC-TM AMVP mode, up to 3 candidates are selected from the IBC Merge list. A template matching method is used to refine each of these 3 selected candidates and they are sorted according to their resulting template matching cost. Then usually only the top 2 are considered during the motion estimation process. Figure 12 The IBC reference region depending on the current CU position is shown. The template matching refinement for both the IBC-TM Merge and AMVP modes is very simple because the IBC motion vectors are constrained to integers and within the reference region as shown in Figure 12 Therefore, in the IBC-TM Merge mode, all refinements are performed with integer precision, and in the IBC-TM AMVP mode, the refinements are performed with integer or 4-pixel precision. In both cases, the refined motion vectors in each refinement step must comply with the constraints of the reference region. 2.8 IBC Merge Mode with Block Vector Difference The IBC Merge mode with block vector difference is as follows. 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 and two vertical directions. Select a base candidate from the top five candidates in the re - ordered IBC Merge list. And based on the SAD cost between the template (one row above and one column to the left of the current block) and the reference at each refinement position, all possible MBVD refinement positions (20×4) for each base candidate are re - ordered. Finally, the top 8 refinement positions with the lowest template SAD cost are kept as available positions and thus used for MBVD index encoding and decoding. 2.9 Reconstruction - Re - ordered IBC (RR - IBC) Intra - block copy (IBC) screen content coding and decoding tools generate a predicted block by directly copying a previously coded and decoded reference region in the same picture. Figure 13 Examples of symmetry in screen content pictures are shown. Symmetry is often observed in video content, especially in text character regions and computer - generated graphics in screen content sequences, such as Figure 13 shown. Therefore, specific screen content coding and decoding tools that consider symmetry will effectively compress such video content. A Reconstruction - Re - ordered IBC (RR - IBC) mode for screen content video coding and decoding is proposed. 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 predicted block is derived without flipping. On the decoder side, the reconstructed block is flipped to restore the original block. For RR - IBC coded and decoded blocks, two flipping methods are supported, namely horizontal flipping and vertical flipping. First, a syntax flag for the IBC AMVP coded and decoded block is signaled to indicate whether the reconstruction is flipped, and if it is flipped, another flag specifying the flip type is further signaled. For IBC Merge, in the absence of syntax signaling, the flip type is inherited from neighboring blocks. Considering horizontal or vertical symmetry, the current block and the reference block are usually horizontally or vertically aligned. Therefore, when horizontal flipping is applied, the vertical component of the BV is not signaled and is presumed to be equal to 0. Similarly, when vertical flipping is applied, the horizontal component of the BV is not signaled and is presumed to be equal to 0. Figure 14A An illustration of BV adjustment for horizontal flipping is shown. Figure 14B An illustration of BV adjustment for vertical flipping is shown. To better utilize the symmetry property, a flip - aware BV adjustment method is applied to refine the block vector candidates. For example, as Figure 14A and Figure 14B shown, (x nbr , y nbr ) and (x cur , y cur ) represent the coordinates of the center samples of the neighboring block and the current block respectively, BV nbr and BVcur respectively represent the BV of the neighboring block and the current block. Instead of directly inheriting the BV from the neighboring block, when the neighboring block is encoded and decoded using horizontal flipping, by adding a motion shift to the horizontal component of the BV nbr (denoted as BV nbr h ) to calculate the horizontal component of BV cur , that is, BV nbr h = 2(x nbr - x cur ) + BV nbr h . Similarly, when the neighboring block is encoded and decoded using vertical flipping, by adding a motion shift to the vertical component of BV nbr (denoted as BV nbr v ) to calculate the vertical component of BV cur , that is, BV cur v = 2(y nbr - y cur ) + BV nbr v . 2.10 Intra-frame template matching Intra-frame template matching prediction (Intra TMP) 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 of intra-frame template matching prediction 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. Figure 15 shows the intra-frame template matching search area used. The prediction signal is generated by matching the L-shaped causal neighbor of the current block with another block in the predefined search area consisting of Figure 15 : R1: the current CTU, R2: the upper left CTU, R3: the upper CTU, R4: the left CTU. SAD is used as the cost function. Within each region, the decoder searches for the template with the minimum SAD relative to the current template and uses its corresponding block as the prediction block. The dimensions of all regions (SearchRange_w, SearchRange_h) are set proportionally to the block dimensions (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 trade-off. In fact, "a" is equal to 5. Enable the intra-frame template matching tool for CUs with dimensions less than or equal to 64 in width and height. This maximum CU size for intra-frame template matching is configurable. When DIMD is not used for the current CU, the intra-frame template matching prediction mode is signaled at the CU level through a dedicated flag. 3. Problem In the current design of IBC, the entire block is directly copied from the reconstructed area in the current picture. However, when illumination changes occur within the current picture, the coding and decoding efficiency of IBC may be limited. 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 sense. In addition, these embodiments can be combined in any way. In the present disclosure, intra-frame block copy (IBC) may not be limited to current IBC technologies, but can be interpreted as a technology in which a reference block (or prediction block) is obtained using samples in the current strip / slice / sub-picture / picture / other video units (e.g., CTU rows), excluding conventional intra-frame prediction methods. In the present disclosure, local illumination compensation (LIC) may not be limited to current LIC technologies. LIC may refer to an inter-frame prediction technology used to model the local illumination change between the current block and its prediction block as a function of the local illumination change between the current block template and the reference block template. The parameters of the function can be represented by a linear equation (e.g., α × p[x] + β) or a non-linear equation. In the present disclosure, CIBCIP (or IBC-CIIP) may refer to a coding and decoding tool that combines intra-frame block copy (IBC) and intra-frame prediction. It is a coding and decoding tool that obtains the prediction of a block using both IBC and intra-frame prediction. In the present disclosure, IBC-GPM may refer to a coding and decoding tool that uses IBC in a video unit to obtain the prediction of at least one sub-division when the video unit is geometrically divided into more than one sub-division. In the following discussion, IBC may be replaced by other coding and decoding tools that rely on encoded / decoded / reconstructed information within the same region, such as a palette, intra-frame template matching. IBC with LIC 1. It is proposed that the refined prediction sample points can be derived as f(p[x]), where p[x] represents the prediction sample points 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 the parameters of a linear equation. b. In one example, the function or at least one parameter of the function can be derived based on the template of the current block. c. In one example, the prediction sample points can be derived by IBC. i. In one example, the function or at least one parameter of the function can be derived based on the template of the reference block of the current block, where the reference block can be located by a block vector (BV). 2. It is proposed that LIC can be applied to compensate the prediction (reconstruction) of a video unit, where IBC is used to obtain the prediction (reconstruction) of the video unit. It is denoted as IBC-LIC. a. In one example, a linear or non-linear equation / model can be used for IBC-LIC to compensate the prediction of a video unit. i. In one example, the linear equation can be α × p[x] + β, where p[x] represents the prediction of the video unit, and α and β represent the parameters of the linear equation. b. In one example, the parameters of the equation used in IBC-LIC can be pre-defined or signaled in the bitstream. c. In one example, the parameters of the equation used in IBC-LIC can be derived using codec information. i. In one example, the current template consists of neighboring reconstructed (adjacent or non-adjacent) sample points of the video unit, and the reference template can be used to derive the parameters. Examples are shown in Figure 16 as follows. 1) In one example, the reference template can be derived using the BV used to obtain the prediction of the video unit. 2) In one example, a part or all of the sample points of the reference template and the current template can be used to derive the parameters. 3) In one example, the least squares error method can be used to derive the parameters. ii. In one example, how to derive the parameters using the current template and the reference template can be the same as that for LIC in inter prediction. d. In one example, a part or all of the prediction sample points of the video unit can be compensated using IBC-LIC. 3. In one example, IBC-LIC can be applied to the IBC AMVP mode and / or the IBC Merge mode. a. In one example, the IBC AMVP mode may refer to the 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 where BV prediction values are derived and BVDs are transmitted / derived via signals. b. In one example, the IBC Merge mode may refer to the normal IBC Merge mode, or IBC-TM Merge mode, or IBC-MBVD mode, or CIBCIP (IBC-CIIP), or IBC-GPM. i. In one example, IBC-LIC may be applied to a specific IBC Merge candidate type. ii. In another example, IBC-LIC may not be allowed to be applied to a specific IBC Merge candidate type. 1) In one example, the Merge candidate type may refer to an RR-IBC candidate. c. Alternatively, IBC-LIC is not allowed to be applied to one or more of the above IBC codec tools. i. In one example, the IBC codec tool may refer to RR-IBC, or CIBCIP (IBC-CIIP), or IBC-GPM. d. In one example, for whether and / or how IBC-LIC is applied to the IBC AMVP mode and / or the IBC Merge mode, codec information may be transmitted or determined via signals. e. In one example, one or more syntax elements may be transmitted via signals to indicate whether and / or how IBC-LIC is applied to the IBC AMVP mode and / or the IBC Merge mode. f. In one example, for whether and / or how IBC-LIC is applied to the IBC Merge mode, it may be inherited. i. In one example, the inheritance of whether and / or how IBC-LIC is applied may be associated with the Merge candidate. 1) In one example, when the Merge candidate is a specific Merge type, IBC-LIC may be disabled. a) In one example, the specific type may refer to RR-IBC. ii. In one example, for whether IBC-LIC is applied to the IBC Merge mode, it may be derived. 1) In one example, a method based on template matching may be used. a) In one example, when IBC-LIC is applied, a first cost (C1) can be calculated between the prediction and the reconstruction of the template of the current video unit; when IBC-LIC is not applied, a second cost (C2) can be calculated between the prediction and the reconstruction of the template of the current video unit. i. In one example, when C1 <= C2, IBC-LIC can be applied; when C1 > C2, IBC-LIC can not be applied. ii. In one example, when C1 <= S * C2, IBC-LIC can be applied; when C1 > S * C2, IBC-LIC can not be applied, where S is a scaling factor. iii. In one example, when C1 <= C2 + O, IBC-LIC can be applied; when C1 > C2 + O, IBC-LIC can not be applied, where O is an offset. 4. In one example, IBC-LIC can be used in the process of reordering the BV candidate list. a. In one example, the BV candidate list can refer to the IBC AMVP candidate list and / or the IBCMerge candidate list. i. In one example, the BV candidate list can refer to the IBC regular Merge list and / or the IBCTM Merge list and / or the IBC-MBVD Merge list. b. In one example, whether and / or how to apply IBC-LIC during the BV candidate list reordering process can be the same as applying IBC-LIC to the current video unit. c. In one example, when IBC-LIC is used for BV candidates, an IBC-LIC model can be used to refine the prediction of the template. i. In one example, the neighboring reconstructed samples of the left / above template and / or the neighboring reconstructed samples of the reference template of the left / above template can be used to derive the IBC-LIC parameters. Examples are shown in Figure 17 below. 1) In one example, the BV associated with the BV candidate can be used to derive the reference template of the left / above template. 2) In one example, the neighboring reconstructed samples of the left / above template and / or the neighboring reconstructed samples of the reference template of the left / above template and / or the left / above template can be constrained in the IBC cache. 3) In one example, when the neighboring reconstructed samples of the left / above template and / or the neighboring reconstructed samples of the reference template of the left / above template and / or the left / above template are outside the IBC cache, IBC-LIC can not be used. a) Alternatively, when neighboring reconstructed samples of the left / upper template and / or neighboring reconstructed samples of the reference template of the left / upper template and / or the left / upper template are outside the IBC cache, samples in the IBC cache can be used to fill the samples outside the IBC cache, and IBC-LIC can be used. d. In one example, IBC-LIC can be applied to one or more BV candidates in the BV candidate list. i. In one example, whether to apply IBC-LIC to a BV candidate can depend on the type of the BV candidate. 1) In one example, the type of the BV candidate can refer to a spatial BV candidate, or an HMVP BV candidate, or a paired BV candidate, or a default BV candidate, or other types of BV candidates. e. In one example, when the BV candidate is RR-IBC (e.g., the RR-IBC flip type is horizontal or vertical), IBC-LIC may not be used. i. Alternatively, IBC-LIC can be used. 1) In one example, the original BV of the BV candidate can be used to derive IBC-LIC parameters. 2) In one example, the adjusted BV of the BV candidate according to the RR-IBC flip type can be used to derive IBC-LIC parameters. f. In one example, a set of IBC-LIC parameters can be derived. i. In one example, the derived set of IBC-LIC parameters can be used for the left and / or upper template. g. In one example, multiple sets of IBC-LIC parameters can be derived. i. In one example, the first set of IBC-LIC parameters can be used for the left template. ii. In one example, the second set of IBC-LIC parameters can be used for the upper template. h. In one example, whether and / or how to apply IBC-LIC to the reordering of the BV candidate list can depend on the specific codec tool using the BV candidate list. i. In one example, when the codec tool is IBC AMVP mode and / or IBC regular Merge mode and / or IBC TM Merge mode and / or IBC-MBVD Merge mode, IBC-LIC can be applied to the reordering of the BV candidate list. ii. Alternatively, when the codec tool is in IBC AMVP mode and / or IBC regular Merge mode and / or IBC TMMerge mode and / or IBC-MBVD Merge mode, IBC-LIC may not be applied to BV candidate list reordering. 5. In one example, when using RR-IBC, IBC-LIC can be used. a. In one example, the position / shape of the template for LIC may depend on whether RR-IBC is applied. b. In one example, the original BV not adjusted according to the RR-IBC flip type can be used to derive IBC-LIC parameters. c. In one example, the adjusted BV according to the RR-IBC flip type can be used to derive IBC-LIC parameters. d. In one example, the original template of the reference block can be used to derive IBC-LIC parameters. i. In one example, the original template of the reference block can be constrained in the IBC cache. ii. In one example, when the original template is not in the IBC cache, IBC- LIC may not be used. 1) Alternatively, when the original template is not in the IBC cache, the samples in the IBC cache can be used to fill the original template, and then the original template can be used in IBC-LIC. e. In one example, the adjusted template of the reference block can be used to derive IBC-LIC parameters. i. In one example, the adjusted template of the reference block can be constrained in the IBC cache. ii. In one example, the adjusted template of the reference block can be adjusted according to the RR-IBC flip type. 1) In one example, when the RR-IBC flip type is horizontal, the adjusted left template and upper template of the reference template can be used. Examples are shown in Figure 18 the figure. 2) In one example, when the RR-IBC flip type is vertical, the adjusted left template and upper template of the reference template can be used. Examples are shown in Figure 19 the figure. iii. In one example, when the adjusted template is not in the IBC cache, IBC-LIC may not be used. 1) Alternatively, when the adjusted template is not in the IBC cache, the samples in the IBC cache can be used to fill the adjusted template, and then the adjusted template can be used in IBC-LIC. f. In one example, IBC-LIC can be used with a specific RR-IBC flip type. i. In one example, the flip type can be horizontal. ii. In one example, the flip type can be vertical. 6. In one example, whether and / or how to apply IBC-LIC can depend on codec information, including: 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 (T1), the block is allowed to be coded / decoded using IBC-LIC, where W and H represent the block width and block height respectively. 1) In one example, T1 = 256, or 512, or 1024, or 2048, or 4096. 2) In one example, T1 can depend on whether the IBC AMVP mode or the IBC Merge mode is used. 3) In one example, T1 can depend on the slice / picture type. ii. In one example, when the block size (W×H) is greater than or equal to a threshold (T2), the block is allowed to be coded / decoded using IBC-LIC, where W and H represent the block width and block height respectively. 1) In one example, T2 = 16, or 32, or 64, or 128, or 256. 2) In one example, T2 can depend on whether the IBC AMVP mode or the IBC Merge mode is used. 3) In one example, T2 can depend on the slice / picture type. iii. In one example, the block size can refer to the luminance block size. b. The codec information can refer to the depth of the block. c. Slice / picture type and / or partition tree type (single tree or dual tree or local dual tree) i. In one example, IBC-LIC can be applied only to I slices / pictures. d. Block position e. Quantization parameter f. Color component. 7. In one example, more than one LIC equation can be used to compensate for the prediction (reconstruction) of video units derived using IBC. a. In one example, multiple LIC types can refer to different LIC equations with adjustment parameters for one or more existing parameters (e.g., α and β) for LIC. i. In one example, an adjustment parameter can be used to adjust α, such as α + u or α × u. ii. In one example, an adjustment parameter can be used to adjust β, such as β + v or β × v. b. In one example, parameters of more than one LIC equation can be derived using different templates. i. In one example, different sample lines of a template can be used. ii. In one example, a left, or top, or top - left template can be used. iii. In one example, samples from different positions in a template can be used. 1) In one instance, the position can refer to a down - sampling position. iv. In one example, samples in different categories can be used. 1) In one example, different categories can be classified depending on the samples of a template. 2) In one example, the average value of samples in a template is used to derive different categories. c. In one example, whether and how to apply one LIC equation among more than one LIC equations can be indicated using a syntax element that is signaled in the bitstream. d. In one example, whether and how to apply one LIC equation among more than one LIC equations can be determined adaptively. 8. In one example, the position / shape of a template can depend on the codec information. a. In one example, if left - hand neighboring samples are not available, the template only contains top - hand neighboring samples. b. In one example, if top - hand neighboring samples are not available, the template only contains left - hand neighboring samples. c. In one instance, if both left - hand and top - hand neighboring samples are not available, IBC - LIC may not be applicable. d. In one example, the template can refer to the template of the current block or the reference block. e. In one example, the position / shape of a template can depend on whether RR - IBC or normal IBC is applied. f. In one instance, the position / shape of a template can consist of one or more sample lines. g. In one example, the position / shape of a template can be pre - defined, or signaled, or derived on - the - fly. h. In one example, the position / shape of a template can depend on the width and height of a video unit. i. In one example, a reference template can be constrained in the IBC cache. i. Alternatively, the reference template may not be restricted in the IBC cache. 9. The determination of whether a block is allowed to be encoded / decoded using the IBC-LIC mode may depend on the encoded / 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 / 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 position. d. Strip / picture type. e. Temporal layer (e.g., temporal layer index). f. Color format. g. Color component. 10. In one example, whether and / or how to apply IBC-LIC may depend on the color format and / or color component. a. In one example, IBC-LIC may be applied to all color components. b. In one example, whether and / or how to apply IBC-LIC to the first component may depend on whether IBC-LIC is applied to the second component. i. In one example, the first component may refer to the chrominance component (e.g., Cb and / or Cr), and the second component may refer to the luminance component (e.g., Y). ii. In one example, the way to apply IBC-LIC to the first component may be the same as that of the second component. 1) Alternatively, the way to apply IBC-LIC to the first component may be different from that of the second component. c. In one example, IBC-LIC may be applied to the luminance component but not to the chrominance component. i. In one example, the luminance component may refer to Y in the YCbCr color space or G in the RGB color space. ii. In one example, the chrominance component may refer to Cb and / or Cr in the YCbCr color space or R and / or B in the RGB color space. Signaling regarding IBC-LIC 11. The indication of the IBC-LIC mode may be signaled conditionally, where the condition may include: a. Whether to allow specific encoding / decoding methods, such as IBC (IBC AMVP or IBC Merge) or RR-IBC or CIBCIP (IBC-CIIP) or IBC-TM or IBC-GPM b. Block dimension and / or block size i. In one example, when the block size (W×H) is less than or equal to a threshold (T3), the indication of the IBC-LIC mode may not be signaled, where W and H represent the block width and block height, respectively. 1) In one example, T3 = 256, or 512, or 1024, or 2048, or 4096. 2) In one example, T3 may depend on whether the IBC AMVP mode or the IBC Merge mode is used. 3) In one example, T3 may depend on the slice / picture type. ii. In one example, when the block size (W×H) is greater than or equal to a threshold (T4), the indication of the IBC-LIC mode may not be signaled, where W and H represent the block width and block height, respectively. 1) In one example, T4 = 16, or 32, or 64, or 128, or 256. 2) In one example, T4 may depend on whether the IBC AMVP mode or the IBC Merge mode is used. 3) In one example, T4 may depend on the slice / picture type. iii. In one example, the block size may refer to the luminance block size. c. Block depth d. Slice / picture type and / or partitioning tree type (single tree or dual tree or local dual tree) e. Temporal layer identifier f. Block position g. Color component h. In one example, the indication of the IBC-LIC mode may not be signaled but deduced. i. In one example, if the indication of the IBC-LIC mode is not signaled, it may be deduced as the default value. i. In one example, if the indication of the IBC-LIC mode is not signaled, it may be deduced as false. ii. In one example, if the indication of the IBC-LIC mode is not signaled, it may be deduced as true. 12. Whether the current block is encoded / decoded using the IBC-LIC mode can be signaled using one or more syntax elements. a. In one example, a syntax element can be binarized using fixed-length coding / decoding, or rounding-unary coding / decoding, or unary coding / decoding, or exponential-Golomb (EG) coding / decoding, or a coding / decoding flag. b. In one example, a syntax element can be bypass-coded or context-coded. i. The context can depend on decoded information, such as block dimension and / or block size, and / or slice / picture type, and / or information of neighboring blocks (adjacent or non-adjacent), and / or information of other coding tools for the current block, and / or information of the temporal layer. 1) In one example, the context can depend on whether neighboring blocks are coded using IBC-LIC. c. In one example, when the current video unit is coded using IBC, an indication of the IBC-LIC mode can be signaled. d. In one example, when the current video unit is coded using the IBC Merge mode, an indication of the IBC-LIC mode can be not signaled. e. In one example, a syntax element can be signaled before or after an indication of a specific coding tool. i. In one example, a specific coding tool can refer to the RR-IBC mode, or the IBC- TM mode, or the IBC-MBVD mode, or CIBCIP (IBC-CIIP), or the IBC- GPM. ii. In one example, whether and / or how a syntax element is signaled can depend on whether the IBC mode, the RR-IBC mode, or the IBC-TM mode, or the IBC- MBVD mode, or CIBCIP (IBC-CIIP), or the IBC-GPM is enabled for the video unit. iii. In one example, a syntax element can be signaled after an indication of the RR-IBC mode. 1) In one example, when the RR-IBC mode is applied, a syntax element indicating IBC-LIC is not signaled and is set to a default value that indicates that IBC-LIC is not applied. iv. In one example, when the video unit is in the IBC AMVP mode, a syntax element can be signaled. f. In one example, one or more syntax elements can be signaled at the sequence header / picture header / SPS / VPS / DPS / DCI / PPS / APS / slice header / picture group header. g. In one example, syntax elements can be encoded and decoded in a predictive manner. h. For example, the syntax elements of the current block can be predicted from the syntax elements of neighboring blocks. i. In one example, whether a block is allowed to be encoded and decoded using the IBC-LIC mode can depend on one or more syntax elements. i. In one example, one or more syntax elements can be signaled as general constraint information. 1) In one example, when a syntax element (e.g., gci_no_ibc_lic_constraint_flag) indicating a general constraint on IBC-LIC is equal to X1 (e.g., X1 = 0 or X1 = 1), IBC-LIC is not allowed. 2) In one example, when a syntax element (e.g., gci_no_ibc_constraint_flag) indicating a general constraint on IBC is equal to X2 (e.g., X2 = 0 or X2 = 1), IBC-LIC is not allowed. ii. In one example, one or more syntax elements can be signaled at the sequence header / picture header / SPS / VPS / DPS / DCI / PPS / APS / strip header / slice group header. General requirements 13. In the above examples, a video unit can refer to a color component / sub-picture / strip / slice / coding tree unit (CTU) / CTU row / CTU group / coding unit (CU) / prediction unit (PU) / transformation unit (TU) / coding tree block (CTB) / coding block (CB) / prediction block (PB) / transformation block (TB) / block / sub-block of a block / sub-region within a block / any other region containing more than one sample or pixel. 14. Whether and / or how to apply the methods disclosed above can be signaled at the sequence level / group of pictures level / picture level / strip level / slice group level, e.g., in the sequence header / picture header / SPS / VPS / DPS / DCI / PPS / PPS / strip header / slice group header. 15. Whether and / or how to apply the methods disclosed above can be signaled at the PB / TB / CB / PU / TU / CU / VPDU / CTU / CTU row / strip / slice / sub-picture / other types of regions containing more than one sample or pixel. 16. Whether and / or how to apply the methods disclosed above can depend on the decoded information, e.g., block size, color format, single / double tree splitting, color component, strip / picture type. 5. Embodiments 5.1 Embodiment 1 In this contribution, three aspects of extending the use of IBC are presented: 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. These two prediction signals are weighted and summed to generate the final prediction. IBC-CIIP can be applied to the IBC AMVP mode and the IBC Merge mode. The CU flag is signaled 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 partitioned into two sub-partitions. Prediction signals for the two sub-partitions are generated using IBC and intra prediction. IBC-GPM can be applied to the IBC Merge mode. The CU flag is signaled 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 change between the CU and its prediction block is modeled as a linear equation. The parameters of the linear equation are derived similar to those used for LIC in inter prediction. IBC-LIC can be applied to the IBC AMVP mode and the IBC Merge mode. For the IBC AMVP mode, the IBC-LIC flag is signaled to indicate the use of IBC-LIC. For the IBC Merge mode, the IBC-LIC flag is deduced from the Merge candidates.

[0077] As used herein, the terms “video unit” or “video block” may be a sequence, picture, slice, tile, sub-picture, coding tree unit (CTU) / coding tree block (CTB), CTU / CTB row, one or more coding units (CU) / coding blocks (CB), one or more CTUs / CTBs, one or more virtual pipeline data units (VPDU), a sub-region within a picture / slice / tile / brick. The term “reference row” may refer to rows and / or columns of reconstructed samples that are adjacent or non-adjacent to the current block and are used to derive the intra prediction of the current video unit via an interpolation filter along a specific direction, and the specific direction is determined by the intra prediction mode (e.g., conventional intra prediction with an intra prediction mode), or to derive the intra prediction of the current video unit via reference samples that weight the reference rows using a matrix or vector (e.g., MIP).

[0078] Figure 20 The flowchart of method 2000 for video processing according to an embodiment of the present disclosure is shown. Method 2000 is implemented during the conversion between the video units of a video and the bitstream of the video.

[0079] At block 2010, a prediction of the video unit is obtained by applying IBC to the video unit.

[0080] At block 2020, a refined prediction of the video unit is obtained by applying LIC to the prediction.

[0081] At block 2030, the conversion is performed based on the refined prediction samples. In some embodiments, the conversion may include encoding the video unit into the bitstream. Alternatively or additionally, the conversion may include decoding the video unit from the bitstream. In this way, the encoding and decoding efficiency and performance can be improved.

[0082] In some embodiments, it is derived whether to apply the IBC-LIC mode for the IBC Merge mode. In some embodiments, a template matching-based method is used to determine whether to apply the IBC-LIC mode for the IBC Merge mode.

[0083] In some embodiments, when the IBC-LIC mode is applied, a first cost is calculated between the prediction and the reconstruction of the template of the video unit, and when the IBC-LIC mode is not applied, a second cost is calculated between the prediction and the reconstruction of the template of the video unit. For example, when the IBC-LIC is applied, a first cost (C1) can be calculated between the prediction and the reconstruction of the template of the current video unit; when the IBC-LIC is not applied, a second cost (C2) can be calculated between the prediction and the reconstruction of the template of the current video unit.

[0084] In some embodiments, if the first cost is less than or equal to the second cost, the IBC-LIC mode is applied. Alternatively or additionally, if the first cost is greater than the second cost, the IBC-LIC mode is not applied. In an example, when C1 <= C2, the IBC-LIC can be applied; when C1 > C2, the IBC-LIC can be not applied.

[0085] In some embodiments, if the first cost is less than or equal to the second cost multiplied by a scaling factor, the IBC-LIC mode is applied. Alternatively or additionally, if the first cost is greater than the second cost multiplied by the scaling factor, the IBC-LIC mode is not applied. In an example, when C1 <= S * C2, the IBC-LIC can be applied; when C1 > S * C2, the IBC-LIC can be not applied, where S is the scaling factor.

[0086] In some embodiments, if the first cost is less than or equal to the sum of the second cost and the offset, the IBC-LIC mode is applied. Alternatively or additionally, if the first cost is greater than the sum of the second cost and the offset, the IBC-LIC mode is not applied. In one example, when C1 <= C2 + O, IBC-LIC can be applied; when C1 > S * C2 + O, IBC-LIC can be not applied, where O is a scaling factor.

[0087] In some embodiments, the IBC-LIC mode is used in the process of reordering a block vector (BV) candidate list. In some embodiments, the BV candidate list is at least one of the following: an IBC advanced motion vector prediction (AMVP) candidate list, or an IBC Merge candidate list. In some embodiments, the BV candidate list is at least one of the following: an IBC regular Merge list, an IBC template matching (TM) Merge list, or an IBC-Merge mode with block vector difference (MBVD) Merge list. In some embodiments, whether the IBC-LIC mode is applied and / or the manner of applying the IBC-LIC mode in the process of reordering the BV candidate list is the same as that of applying the IBC-LIC mode to a video unit.

[0088] In some embodiments, if the IBC-LIC mode is used for a BV candidate, the prediction of the template of the video unit is refined using the IBC-LIC mode. In some embodiments, at least one of the following is used to derive the parameters of the IBC-LIC mode: neighboring reconstructed samples of the left or upper template, or neighboring reconstructed samples of the reference template of the left or upper template. For example, as Figure 17 shown. In some embodiments, the reference template of the left or upper template is derived using the BV associated with the BV candidate. In some embodiments, at least one of the following is constrained in the IBC cache: neighboring reconstructed samples of the left or upper template, neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template.

[0089] In some embodiments, if at least one of the following is outside the IBC cache: neighboring reconstructed samples of the left or upper template, neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template, the IBC-LIC mode is not used. In some other embodiments, if at least one of the following is outside the IBC cache: neighboring reconstructed samples of the left or upper template, neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template, the samples outside the IBC cache are filled with the samples in the IBC cache, and the IBC-LIC mode is used.

[0090] In some embodiments, the IBC-LIC mode is applied to one or more BV candidates in the BV candidate list. In some embodiments, whether to apply the IBC-LIC mode to a BV candidate depends on the type of the BV candidate. In some embodiments, the type of the BV candidate includes one of the following: a spatial BV candidate, a history-based motion vector prediction (HMVP) BV candidate, a paired BV candidate, a default BV candidate, or other types of BV candidates.

[0091] In some embodiments, if the BV candidate is a reconstructed and reordered IBC (RR-IBC), the IBC-LIC mode is not used. In one example, when the BV candidate is RR-IBC (e.g., the RR-IBC flip type is horizontal or vertical), the IBC-LIC may not be used. Alternatively, if the BV candidate is RR-IBC, the IBC-LIC mode is used.

[0092] In some embodiments, the original BV of the BV candidate is used to derive the IBC-LIC parameters. In some embodiments, the adjusted BV of the BV candidate according to the RR-IBC flip type is used to derive the IBC-LIC parameters.

[0093] In some embodiments, a set of IBC-LIC parameters is derived. In some embodiments, the derived set of IBC-LIC parameters is used for at least one of the left template or the upper template.

[0094] In some embodiments, multiple sets of IBC-LIC parameters are derived. In some embodiments, the first set of IBC-LIC parameters among the multiple sets of IBC-LIC parameters is used for the left template. Alternatively or additionally, the second set of IBC-LIC parameters among the multiple sets of IBC-LIC parameters is used for the upper template.

[0095] In some embodiments, whether to apply the IBC-LIC mode to the BV candidate list reordering and / or the way of applying the IBC-LIC mode to the BV candidate list reordering depends on the codec tool using the BV candidate list. In some embodiments, if the codec tool is at least one of the following, the IBC-LIC mode is applied to the process of reordering the BV candidate list: the IBC AMVP mode, the IBC regular Merge mode, the IBC TM Merge mode, or the IBC-MBVD Merge mode. In some other embodiments, if the codec tool is at least one of the following, the IBC-LIC mode is not applied to the process of reordering the BV candidate list: the IBC AMVP mode, the IBC regular Merge mode, the IBC TM Merge mode, or the IBC-MBVD Merge mode.

[0096] In some embodiments, if RR-IBC is used, the IBC-LIC mode is used. In some embodiments, at least one of the position or shape of the template used for LIC depends on whether RR-IBC is applied.

[0097] In some embodiments, the original BV that is not adjusted according to the RR-IBC flip type is used to derive IBC-LIC parameters. In some embodiments, the adjusted BV according to the RR-IBC flip type is used to derive IBC-LIC parameters.

[0098] In some embodiments, the original template of the reference block is used to derive IBC-LIC parameters. In some embodiments, the original template of the reference block is constrained in the IBC cache. In some embodiments, if the original template is not in the IBC cache, the IBC-LIC mode is not used. In some embodiments, if the original template is not in the IBC cache, the original template is filled with samples in the IBC cache, and the filled original template is used in the IBC-LIC mode.

[0099] In some embodiments, the adjusted template of the reference block is used to derive IBC-LIC parameters. In some embodiments, the adjusted template of the reference block is constrained in the IBC cache. In some embodiments, the adjusted template of the reference block is adjusted according to the RR-IBC flip type.

[0100] In some embodiments, if the RR-IBC flip type is horizontal, the adjusted left and upper templates of the reference template are used, for example, as Figure 18 shown. In some embodiments, if the RR-IBC flip type is vertical, the adjusted left and upper templates of the reference template are used, for example, as Figure 19 shown.

[0101] In some embodiments, if the adjusted template is not in the IBC cache, the IBC-LIC mode is not used. In some embodiments, if the adjusted template is not in the IBC cache, the adjusted template is filled with samples in the IBC cache, and then the filled template is used in the IBC-LIC mode.

[0102] In some embodiments, the IBC-LIC mode is used together with the RR-IBC flip type. In some embodiments, the RR-IBC flip type is horizontal. Alternatively, the RR-IBC flip type is vertical.

[0103] In some embodiments, whether to apply the IBC-LIC mode and / or the way of applying the IBC-LIC mode depends on the coding and decoding information of the video unit, and the coding 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.

[0104] In some embodiments, when the block size is less than or equal to a first threshold, the block is allowed to be coded and decoded using the IBC-LIC mode, where the block size is equal to WH, and W and H represent the block width and block height of the block, respectively. In some embodiments, the first threshold is equal to one of 256, 512, 1024, 2048, or 4096. In some embodiments, the first threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used. In some embodiments, the first threshold depends on the slice type or the picture type.

[0105] In some embodiments, when the block size is greater than or equal to a second threshold, the block is allowed to be coded and decoded using the IBC-LIC mode, where the block size is equal to WH, and W and H represent the block width and block height of the block, respectively. In some embodiments, the second threshold is equal to one of 16, 32, 64, 128, or 256. In some embodiments, the second threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used. In some embodiments, the second threshold depends on the slice type or the picture type. In some embodiments, the block size refers to the luma block size.

[0106] In some embodiments, the indication of the IBC-LIC mode is indicated based on a condition. Alternatively, the indication of the IBC-LIC mode is derived. In some embodiments, the condition includes at least one of the following: whether the target coding and decoding method is allowed; block dimension, block size, block depth, slice type, picture type, partition tree type, temporal layer identifier, block position, or color component.

[0107] In some embodiments, when the block size is less than or equal to a third threshold, the indication of the IBC-LIC mode is not indicated, where the block size is equal to WH, and W and H represent the block width and block height of the block, respectively. In some embodiments, the third threshold is equal to one of 256, 512, 1024, 2048, or 4096. In some embodiments, the third threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used. In some embodiments, the third threshold depends on the slice type or the picture type.

[0108] In some embodiments, when the block size is greater than or equal to a fourth threshold, the indication of the IBC-LIC mode is not indicated, where the block size is equal to WH, and W and H represent the block width and block height of the block, respectively. In some embodiments, the fourth threshold is equal to one of 16, 32, 64, 128, or 256. In some embodiments, the fourth threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used. In some embodiments, the fourth threshold depends on the slice type or the picture type. In some embodiments, the block size refers to the luma block size.

[0109] In some embodiments, if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be the default value. In some embodiments, if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be false. In some embodiments, if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be true.

[0110] In some embodiments, whether a video unit is encoded or decoded using IBC with the LIC mode is indicated using at least one syntax element. In some embodiments, when a video unit is encoded or decoded using the IBC Merge mode, the indication of the IBC-LIC mode is not indicated. In some embodiments, whether a block is allowed to be encoded or decoded using the IBC-LIC mode depends on one or more syntax elements. In some embodiments, one or more syntax elements are indicated as general constraint information.

[0111] In some embodiments, when the syntax element indicating the general constraint on IBC-LIC is equal to a first value, the IBC-LIC mode is not allowed. Alternatively, when the syntax indicating the general constraint on IBC is equal to a second value, IBC-LIC is not allowed. In some embodiments, the syntax element is gci_no_ibc_constraint_flag. Alternatively or additionally, the first value is 0 or 1. Alternatively or additionally, the second value is 0 or 1. In some embodiments, one or more syntax elements are indicated at one of the following: sequence header, picture header, sequence parameter set (SPS), video parameter set (VPS), dependency parameter set (DPS), decoding capability information (DCI), picture parameter set (PPS), adaptive parameter set (APS), slice header, or slice group header.

[0112] In some embodiments, a 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 picture, a sub-picture, a block, a sub-region within a block, or a region containing more than one sample or pixel. In some embodiments, an indication of whether and / or how to derive refined prediction samples of a video unit by applying the IBC-LIC mode is indicated at one of the following: sequence level, group of pictures level, picture level, slice level, or slice group level.

[0113] In some embodiments, an indication of whether and / or how to derive refined prediction samples of a video unit by applying the IBC-LIC mode is indicated at one of the following: sequence header, picture header, sequence parameter set (SPS), video parameter set (VPS), dependency parameter set (DPS), decoding capability information (DCI), picture parameter set (PPS), adaptive parameter set (APS), slice header, or slice group header. In some embodiments, an indication of whether and / or how to derive refined prediction samples of a video unit by applying the IBC-LIC mode is indicated at one of the following: PB, TB, CB, PU, TU, CU, VPDU, CTU, CTU row, slice, picture, sub-picture; or a region containing more than one sample or pixel.

[0114] In some embodiments, whether and / or how to derive refined prediction samples of a video unit by applying the IBC-LIC mode is codec information of the video unit. The codec information includes at least one of the following: block size, color format, single-tree segmentation, double-tree segmentation, color component, slice type, or picture type.

[0115] According to further embodiments of the present disclosure, a non-transitory computer-readable recording medium is provided. The non-transitory computer-readable recording medium stores a bitstream generated by a method executed by an apparatus for video processing for a video. The method includes: determining whether to apply an intra block copy (IBC) and local illumination compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving refined prediction of the video unit includes: obtaining prediction of the video unit by applying IBC to the video unit; and obtaining refined prediction of the video unit by applying LIC to the prediction; and generating a bitstream based on the refined prediction.

[0116] According to another embodiment of the present disclosure, a method for storing a bitstream of a video is provided. The method includes: determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying the IBC to the video unit; and obtaining the refined prediction of the video unit by applying the LIC to the prediction; generating a bitstream based on the refined prediction; and storing the bitstream in a non-transitory computer-readable recording medium.

[0117] The implementations of the present disclosure can be described according to the following items, and the features can be combined in any reasonable manner.

[0118] Item 1. A method for video processing, including: determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying the IBC to the video unit; and obtaining the refined prediction of the video unit by applying the LIC to the prediction; and performing the conversion based on the refined prediction samples.

[0119] Item 2. The method according to Item 1, wherein it is derived whether to apply the IBC-LIC mode for the IBC Merge mode.

[0120] Item 3. The method according to Item 2, wherein a template matching-based method is used to determine whether to apply the IBC-LIC mode for the IBC Merge mode.

[0121] Item 4. The method according to Item 3, wherein when the IBC-LIC mode is applied, a first cost is calculated between the prediction and the reconstruction of the template of the video unit, and wherein when the IBC-LIC mode is not applied, a second cost is calculated between the prediction and the reconstruction of the template of the video unit.

[0122] Item 5. The method according to Item 4, wherein if the first cost is less than or equal to the second cost, the IBC-LIC mode is applied; and / or wherein if the first cost is greater than the second cost, the IBC-LIC mode is not applied.

[0123] Item 6. The method according to Item 4, wherein if the first cost is less than or equal to the second cost multiplied by a scaling factor, the IBC-LIC mode is applied; and / or wherein if the first cost is greater than the second cost multiplied by the scaling factor, the IBC-LIC mode is not applied.

[0124] Item 7. The method according to Item 4, wherein if the first cost is less than or equal to the sum of the second cost and an offset, the IBC-LIC mode is applied; and / or wherein if the first cost is greater than the sum of the second cost and the offset, the IBC-LIC mode is not applied.

[0125] Item 8. The method according to Item 1, wherein the IBC-LIC mode is used in the process of reordering a block vector (BV) candidate list.

[0126] Item 9. The method according to Item 8, wherein the BV candidate list is at least one of the following: an IBC advanced motion vector prediction (AMVP) candidate list, or an IBC Merge candidate list.

[0127] Item 10. The method according to Item 8, wherein the BV candidate list is at least one of the following: an IBC regular Merge list, an IBC template matching (TM) Merge list, or an IBC-Merge mode with block vector difference (MBVD) Merge list.

[0128] Item 11. The method according to Item 8, wherein whether the IBC-LIC mode is applied and / or the manner of applying the IBC-LIC mode in the process of reordering the BV candidate list is the same as the manner of applying the IBC-LIC mode to the video unit.

[0129] Item 12. The method according to Item 8, wherein if the IBC-LIC mode is used for a BV candidate, the prediction of the template of the video unit is refined using the IBC-LIC mode.

[0130] Item 13. The method according to Item 12, wherein at least one of the following is used to derive the parameters of the IBC-LIC mode: neighboring reconstructed samples of the left or upper template, or neighboring reconstructed samples of the reference template of the left or upper template.

[0131] Item 14. The method according to Item 13, wherein the reference template of the left or upper template is derived using the BV associated with the BV candidate.

[0132] Item 15. The method according to Item 13, wherein at least one of the following is constrained in the IBC cache: the neighboring reconstructed samples of the left or upper template, the neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template.

[0133] Item 16. The method according to Item 13, wherein if at least one of the following is outside the IBC cache: the neighboring reconstructed samples of the left or upper template, the neighboring shock-like samples of the reference template of the left or upper template, or the left or upper template, the IBC-LIC mode is not used.

[0134] Item 17. The method according to Item 13, wherein if at least one of the following is outside the IBC cache: the neighboring reconstructed samples of the left or upper template, the neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template, the samples outside the IBC cache are filled using the samples in the IBC cache, and the IBC-LIC mode is used.

[0135] Item 18. The method according to Item 8, wherein the IBC-LIC mode is applied to one or more BV candidates in the BV candidate list.

[0136] Item 19. The method according to Item 18, wherein whether to apply the IBC-LIC mode to a BV candidate depends on the type of the BV candidate.

[0137] Item 20. The method according to Item 19, wherein the type of the BV candidate includes one of the following: a spatial-domain BV candidate, a history-based motion vector prediction (HMVP) BV candidate, a paired BV candidate, a default BV candidate, or other types of BV candidates.

[0138] Item 21. The method according to Item 8, wherein if the BV candidate is a reconstructed-reordered IBC (RR-IBC), the IBC-LIC mode is not used, or wherein if the BV candidate is RR-IBC, the IBC-LIC mode is used.

[0139] Item 22. The method according to Item 21, wherein the original BV of the BV candidate is used to derive the IBC-LIC parameters.

[0140] Item 23. The method according to Item 21, wherein the adjusted BV of the BV candidate according to the RR-IBC flip type is used to derive the IBC-LIC parameter.

[0141] Item 24. The method according to Item 8, wherein a set of IBC-LIC parameters is derived.

[0142] Item 25. The method according to Item 24, wherein the derived set of IBC-LIC parameters is used for at least one of the left template or the upper template.

[0143] Item 26. The method according to Item 8, wherein multiple sets of IBC-LIC parameters are derived.

[0144] Item 27. The method according to Item 26, wherein the first set of IBC-LIC parameters in the multiple sets of IBC-LIC parameters is used for the left template, and / or wherein the second set of IBC-LIC parameters in the multiple sets of IBC-LIC parameters is used for the upper template.

[0145] Item 28. The method according to Item 8, wherein whether to apply the IBC-LIC mode to reorder the BV candidate list and / or the way to apply the IBC-LIC mode to reorder the BV candidate list depends on the codec tool using the BV candidate list.

[0146] Item 29. The method according to Item 28, wherein if the codec tool is at least one of the following, the IBC-LIC mode is applied to the process of reordering the BV candidate list: IBC AMVP mode, IBC normal Merge mode, IBC TM Merge mode, or IBC-MBVD Merge mode.

[0147] Item 30. The method according to Item 28, wherein if the codec tool is at least one of the following, the IBC-LIC mode is not applied to the process of reordering the BV candidate list: IBC AMVP mode, IBC normal Merge mode, IBC TM Merge mode, or IBC-MBVD Merge mode.

[0148] Item 31. The method according to Item 1, wherein if RR-IBC is used, the IBC-LIC mode is used.

[0149] Item 32. The method according to Item 31, wherein at least one of the position or shape of the template used for LIC depends on whether RR-IBC is applied.

[0150] Item 33. The method according to Item 31, wherein the original BV that is not adjusted according to the RR-IBC flip type is used to derive the IBC-LIC parameter.

[0151] Item 34. The method according to Item 31, wherein the adjusted BV according to the RR-IBC flip type is used to derive the IBC-LIC parameter.

[0152] Item 35. The method according to Item 31, wherein the original template of the reference block is used to derive the IBC-LIC parameter.

[0153] Item 36. The method according to Item 35, wherein the original template of the reference block is constrained in the IBC cache.

[0154] Item 37. The method according to Item 35, wherein if the original template is not in the IBC cache, the IBC-LIC mode is not used.

[0155] Item 38. The method according to Item 35, wherein if the original template is not in the IBC cache, the original template is filled with samples in the IBC cache, and the filled original template is used in the IBC-LIC mode.

[0156] Item 39. The method according to Item 31, wherein the adjusted template of the reference block is used to derive the IBC-LIC parameter.

[0157] Item 40. The method according to Item 39, wherein the adjusted template of the reference block is constrained in the IBC cache.

[0158] Item 41. The method according to Item 39, wherein the adjusted template of the reference block is adjusted according to the RR-IBC flip type.

[0159] Item 42. The method according to Item 41, wherein if the RR-IBC flip type is horizontal, the adjusted left and upper templates of the reference template are used.

[0160] Item 43. The method according to Item 41, wherein if the RR-IBC flip type is vertical, the adjusted left and upper templates of the reference template are used.

[0161] Item 44. The method according to Item 39, wherein if the adjusted template is not in the IBC cache, the IBC-LIC mode is not used.

[0162] Item 45. The method according to Item 39, wherein if the adjusted template is not in the IBC cache, the adjusted template is filled with samples in the IBC cache, and the subsequently filled template is used in the IBC-LIC mode.

[0163] Item 46. The method according to Item 31, wherein the IBC-LIC mode is used together with the RR-IBC flip type.

[0164] Item 47. The method according to Item 46, wherein the RR-IBC flip type is horizontal, or wherein the RR-IBC flip type is vertical.

[0165] Item 48. The method according to any one of Items 1 to 47, wherein whether the IBC-LIC mode is applied and / or the manner of applying the IBC-LIC mode depends on the codec information of the video unit, and wherein the codec information of the video unit includes at least one of the following: block dimension, block size, depth of the video unit, stripe type, picture type, segmentation tree type, block position, quantization parameter, or color component.

[0166] Item 49. The method according to Item 48, wherein when the block size is less than or equal to a first threshold, the block is allowed to be coded and decoded using the IBC-LIC mode, wherein the block size is equal to W×H, and W and H represent the block width and block height of the block, respectively.

[0167] Item 50. The method according to Item 49, wherein the first threshold is equal to one of 256, 512, 1024, 2048, or 4096.

[0168] Item 51. The method according to Item 49, wherein the first threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used.

[0169] Item 52. The method according to Item 49, wherein the first threshold depends on the stripe type or the picture type.

[0170] Item 53. The method according to Item 48, wherein when the block size is greater than or equal to a second threshold, the block is allowed to be coded and decoded using the IBC-LIC mode, wherein the block size is equal to W×H, and W and H represent the block width and block height of the block, respectively.

[0171] Item 54. The method according to Item 53, wherein the second threshold is equal to one of 16, 32, 64, 128, or 256.

[0172] Item 55. The method according to item 53, wherein the second threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used.

[0173] Item 56. The method according to item 53, wherein the second threshold depends on the slice type or the picture type.

[0174] Item 57. The method according to any one of items 48 to 53, wherein the block size refers to the luma block size.

[0175] Item 58. The method according to item 1, wherein the indication of the IBC-LIC mode is indicated based on a condition, or wherein the indication of the IBC-LIC mode is derived.

[0176] Item 59. The method according to item 58, wherein 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, split tree type, temporal layer identifier, block position, or color component.

[0177] Item 60. The method according to item 59, wherein when the block size is less than or equal to a third threshold, the indication of the IBC-LIC mode is not indicated, wherein the block size is equal to W×H, and W and H respectively represent the block width and the block height of the block.

[0178] Item 61. The method according to item 60, wherein the third threshold is equal to one of 256, 512, 1024, 2048, or 4096.

[0179] Item 62. The method according to item 60, wherein the third threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used.

[0180] Item 63. The method according to item 60, wherein the third threshold depends on the slice type or the picture type.

[0181] Item 64. The method according to item 59, wherein when the block size is greater than or equal to a fourth threshold, the indication of the IBC-LIC mode is not indicated, wherein the block size is equal to W×H, and W and H respectively represent the block width and the block height of the block.

[0182] Item 65. The method according to item 64, wherein the fourth threshold is equal to one of 16, 32, 64, 128, or 256.

[0183] Item 66. The method according to Item 64, wherein the fourth threshold depends on whether the IBC AMVP mode or the IBC Merge mode is used.

[0184] Item 67. The method according to Item 64, wherein the fourth threshold depends on the slice type or the picture type.

[0185] Item 68. The method according to any one of Items 59 to 67, wherein the block size refers to the luminance block size.

[0186] Item 69. The method according to Item 58, wherein if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be the default value.

[0187] Item 70. The method according to Item 69, wherein if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be false.

[0188] Item 71. The method according to Item 69, wherein if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be true.

[0189] Item 72. The method according to Item 1, wherein whether the video unit is encoded or decoded using IBC with the LIC mode is indicated using at least one syntax element.

[0190] Item 73. The method according to Item 72, wherein when the video unit is encoded or decoded using the IBC Merge mode, the indication of the IBC-LIC mode is not indicated.

[0191] Item 74. The method according to Item 27, wherein whether a block is allowed to be encoded or decoded using the IBC-LIC mode depends on one or more syntax elements.

[0192] Item 75. The method according to Item 74, wherein the one or more syntax elements are indicated as general constraint information.

[0193] Item 76. The method according to Item 75, wherein when the syntax element indicating the general constraint on IBC-LIC is equal to the first value, the IBC-LIC mode is not allowed, or wherein when the syntax indicating the general constraint on IBC is equal to the second value, the IBC-LIC is not allowed.

[0194] Item 77. The method according to Item 76, wherein the syntax element is gci_no_ibc_constraint_flag, and / or wherein the first value is 0 or 1, and / or wherein the second value is 0 or 1.

[0195] Item 78. The method according to Item 74, wherein the one or more syntax elements are indicated at one of the following: sequence header, picture header, sequence parameter set (SPS), video parameter set (VPS), dependency parameter set (DPS), decoding capability information (DCI), picture parameter set (PPS), adaptive parameter set (APS), slice header, or slice group header.

[0196] Item 79. The method according to any one of Items 1 to 78, wherein the video unit includes at least one of the following: color component, prediction block (PB), transform block (TB), codec block (CB), prediction unit (PU), transform unit (TU), codec tree block (CTB), codec unit (CU), codec tree unit (CTU), CTU row, CTU group, slice, picture, sub-picture, block, sub-region within a block, or region containing more than one sample or pixel.

[0197] Item 80. The method according to any one of Items 1 to 78, wherein the indication of whether and / or how to derive the refined prediction samples of the video unit by applying the IBC-LIC mode is indicated at one of the following: sequence level, picture group level, picture level, slice level, or slice group level.

[0198] Item 81. The method according to any one of Items 1 to 78, wherein the indication of whether and / or how to derive the refined prediction samples of the video unit by applying the IBC-LIC mode is indicated at one of the following: sequence header, picture header, sequence parameter set (SPS), video parameter set (VPS), dependency parameter set (DPS), decoding capability information (DCI), picture parameter set (PPS), adaptive parameter set (APS), slice header, or slice group header.

[0199] Item 82. The method according to any one of Items 1 to 78, wherein the indication of whether and / or how to derive the refined prediction samples of the video unit by applying the IBC-LIC mode is indicated at one of the following: PB, TB, CB, PU, TU, CU, VPDU, CTU, CTU row, slice, picture, sub-picture; or region containing more than one sample or pixel.

[0200] Item 83. The method according to any one of Items 1 to 78, wherein whether and / or how to derive the refined prediction samples of the video unit by applying the IBC-LIC mode is the transcoded information of the video unit, and wherein the transcoded information includes at least one of the following: block size, color format, single-tree segmentation, double-tree segmentation, color component, slice type, or picture type.

[0201] Item 84. The method according to any one of Items 1 to 78, wherein the transformation includes encoding the video unit into the bitstream.

[0202] Item 85. The method according to any one of Items 1 to 78, wherein the transformation includes decoding the video unit from the bitstream.

[0203] Item 86. An apparatus for video processing, including a processor and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to execute the method according to any one of Items 1 to 85.

[0204] Item 87. A non-transitory computer-readable storage medium storing instructions that cause a processor to execute the method according to any one of Items 1 to 85.

[0205] Item 88. A non-transitory computer-readable recording medium storing a bitstream generated by a method executed by an apparatus for video processing for a video, wherein the method includes: determining whether to apply an intra block copy (IBC) and local illumination compensation (LIC) (IBC-LIC) mode to a video unit for transformation between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying the IBC to the video unit; and obtaining the refined prediction of the video unit by applying the LIC to the prediction; and generating the bitstream based on the refined prediction.

[0206] Item 89. A method for storing a bitstream of video, comprising: determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; if it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit includes: obtaining a prediction of the video unit by applying the IBC to the video unit; and obtaining the refined prediction of the video unit by applying the LIC to the prediction; generating the bitstream based on the refined prediction; and storing the bitstream in a non-transitory computer-readable recording medium. Example device

[0207] Figure 21 FIG. shows a block diagram of a computing device 2100 in which various embodiments of the present disclosure may be implemented. The computing device 2100 may be implemented as the source device 110 (or video encoder 114 or 200) or the destination device 120 (or video decoder 124 or 300), or may be included in the source device 110 (or video encoder 114 or 200) or the destination device 120 (or video decoder 124 or 300).

[0208] It should be understood that Figure 21 the computing device 2100 shown in is for illustrative purposes only and does not imply any limitation to the functionality and scope of the embodiments of the present disclosure in any way.

[0209] As Figure 21 shown, the computing device 2100 includes a general-purpose computing device 2100. The computing device 2100 may include at least one or more processors or processing units 2110, a memory 2120, a storage unit 2130, one or more communication units 2140, one or more input devices 2150, and one or more output devices 2160.

[0210] In some embodiments, computing device 2100 may be implemented as any user terminal or server terminal having computing capabilities. The server terminal may be a server provided by a service provider, a large computing device, etc. The user terminal may be, for example, any type of mobile terminal, fixed terminal, or portable terminal, including mobile phones, stations, units, devices, multimedia computers, multimedia tablet computers, Internet nodes, communicators, desktop computers, laptop computers, notebook computers, netbook computers, tablet computers, personal communication system (PCS) devices, personal navigation devices, personal digital assistant (PDA), audio / video players, digital cameras / video cameras, positioning devices, television receivers, radio broadcast receivers, e-book devices, gaming devices, or any combination thereof, including accessories and peripherals of these devices or any combination thereof. It is contemplated that computing device 2100 may support any type of interface to the user (such as "wearable" circuitry, etc.).

[0211] Processing unit 2110 may be a physical processor or a virtual processor, and may implement various processes based on programs stored in memory 2120. In a multi-processor system, multiple processing units execute computer-executable instructions in parallel to improve the parallel processing ability of computing device 2100. Processing unit 2110 may also be referred to as a central processing unit (CPU), microprocessor, controller, or microcontroller.

[0212] Computing device 2100 generally includes various computer storage media. Such media may be any media accessible by computing device 2100, including but not limited to volatile media and non-volatile media, or removable media and non-removable media. Memory 2120 may be volatile memory (e.g., registers, caches, random access memory (RAM)), non-volatile memory (such as read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), or flash memory), or any combination thereof. Storage unit 2130 may be any removable or non-removable media, and may include machine-readable media, such as memory, flash drive, disk, or other media that can be used to store information and / or data and can be accessed in computing device 2100.

[0213] Computing device 2100 may also include additional removable / non-removable storage media, volatile / non-volatile storage media. Although not shown in Figure 21 A disk drive for reading and / or writing to a removable non-volatile disk and an optical disk drive for reading and / or writing to a removable non-volatile optical disk may be provided. In this case, each drive may be connected to a bus (not shown) via one or more data media interfaces.

[0214] The communication unit 2140 communicates with another computing device via a communication medium. Additionally, the functionality of the components in the computing device 2100 can be implemented by a single computing cluster or multiple computer machines, which can communicate via a communication connection. Thus, the computing device 2100 can operate in a networked environment using logical connections with one or more other servers, networked personal computers (PCs), or other general network nodes.

[0215] The input device 2150 can be one or more of a variety of input devices, such as a mouse, keyboard, trackball, voice input device, and so on. The output device 2160 can be one or more of a variety of output devices, such as a display, speaker, printer, and so on. With the aid of the communication unit 2140, the computing device 2100 can also communicate with one or more external devices (not shown), such as storage devices and display devices, the computing device 2100 can also communicate with one or more devices that enable a user to interact with the computing device 2100, or if needed, the computing device 2100 can also communicate with any device (such as a network card, modem, etc.) that enables the computing device 2100 to communicate with one or more other computing devices. Such communication can be carried out via an input / output (I / O) interface (not shown).

[0216] In some embodiments, some or all of the components of the computing device 2100 can also be arranged in a cloud computing architecture rather than being integrated in a single device. In a cloud computing architecture, the components can be provided remotely and work together to implement the functions described in this disclosure. In some embodiments, cloud computing provides computing, software, data access, and storage services, which will not require an end user to be aware of the physical location or configuration of the system or hardware providing these services. In various embodiments, cloud computing uses suitable protocols to provide services via a wide area network (such as the Internet). For example, a cloud computing provider provides an application via a wide area network, and the application can be accessed via a web browser or any other computing component. The software or components of the cloud computing architecture and the corresponding data can be stored on a server at a remote location. The computing resources in a cloud computing environment can be consolidated or distributed at the locations of remote data centers. The cloud computing infrastructure can provide services through a shared data center, although to a user, they appear as a single access point. Thus, a cloud computing architecture can 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 can be provided by a conventional server or directly or otherwise installed on a client device.

[0217] In an embodiment of the present disclosure, the computing device 2100 can be used to implement video encoding / decoding. The memory 2120 may include one or more video codec modules 2125 having one or more program instructions. These modules are accessible and executable by the processing unit 2110 to perform the functions of the various embodiments described herein.

[0218] In an example embodiment of performing video encoding, the input device 2150 may receive video data as input 2170 to be encoded. The video data may be processed, for example, by the video codec module 2125 to generate an encoded bitstream. The encoded bitstream may be provided as output 2180 via the output device 2160.

[0219] In an example embodiment of performing video decoding, the input device 2150 may receive the encoded bitstream as input 2170. The encoded bitstream may be processed, for example, by the video codec module 2125 to generate decoded video data. The decoded video data may be provided as output 2180 via the output device 2160.

[0220] Although the present disclosure has been specifically shown and described with reference to preferred embodiments of the present disclosure, those skilled in the art will understand 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 variations are intended to be covered 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 method for video processing, comprising: Determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for the conversion between the video unit of a video and the bitstream of the video unit; If it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit comprises: Obtaining a prediction of the video unit by applying the IBC to the video unit; and Obtaining the refined prediction of the video unit by applying the LIC to the prediction; and performing the conversion based on the refined prediction samples.

2. The method according to claim 1, wherein it is derived whether to apply the IBC-LIC mode for the IBC Merge mode.

3. The method according to claim 2, wherein a template matching-based method is used to determine whether to apply the IBC-LIC mode for the IBC Merge mode.

4. The method according to claim 3, wherein when the IBC-LIC mode is applied, a first cost is calculated between the prediction of the template of the video unit and the reconstruction of the template, and wherein when the IBC-LIC mode is not applied, a second cost is calculated between the prediction of the template of the video unit and the reconstruction of the template.

5. The method according to claim 4, wherein if the first cost is less than or equal to the second cost, the IBC-LIC mode is applied; and / or wherein if the first cost is greater than the second cost, the IBC-LIC mode is not applied.

6. The method according to claim 4, wherein if the first cost is less than or equal to the second cost multiplied by a scaling factor, the IBC-LIC mode is applied; and / or wherein if the first cost is greater than the second cost multiplied by the scaling factor, the IBC-LIC mode is not applied.

7. The method according to claim 4, wherein if the first cost is less than or equal to the sum of the second cost and an offset, the IBC-LIC mode is applied; and / or wherein if the first cost is greater than the sum of the second cost and the offset, the IBC-LIC mode is not applied.

8. The method according to claim 1, wherein the IBC-LIC mode is used in the process of reordering a Block Vector (BV) candidate list.

9. The method according to claim 8, wherein the BV candidate list is at least one of the following: IBC Advanced Motion Vector Prediction (AMVP) candidate list, or IBC Merge candidate list.

10. The method according to claim 8, wherein the BV candidate list is at least one of the following: IBC regular Merge list, IBC Template Matching (TM) Merge list, or IBC - Merge list with Motion Block Vector Difference (MBVD) in Merge mode.

11. The method according to claim 8, wherein whether the IBC - LIC mode is applied and / or the manner of applying the IBC - LIC mode during the re - ordering of the BV candidate list is the same as the manner of applying the IBC - LIC mode to the video unit.

12. The method according to claim 8, wherein if the IBC - LIC mode is used for a BV candidate, the prediction of the template of the video unit is refined using the IBC - LIC mode.

13. The method according to claim 12, wherein at least one of the following is used to derive the parameters of the IBC - LIC mode: neighboring reconstructed samples of the left or upper template, or neighboring reconstructed samples of the reference template of the left or upper template.

14. The method according to claim 13, wherein the reference template of the left or upper template is derived using the BV associated with the BV candidate.

15. The method according to claim 13, wherein at least one of the following is constrained in the IBC cache: the neighboring reconstructed samples of the left or upper template, the neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template.

16. The method according to claim 13, wherein if at least one of the following is outside the IBC cache: the neighboring reconstructed samples of the left or upper template, the neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template, the IBC - LIC mode is not used.

17. The method according to claim 13, wherein if at least one of the following is outside the IBC cache: the neighboring reconstructed samples of the left or upper template, the neighboring reconstructed samples of the reference template of the left or upper template, or the left or upper template, the samples outside the IBC cache are filled with the samples in the IBC cache, and the IBC - LIC mode is used.

18. The method according to claim 8, wherein the IBC - LIC mode is applied to one or more BV candidates in the BV candidate list.

19. The method according to claim 18, wherein whether the IBC - LIC mode is applied to a BV candidate depends on the type of the BV candidate.

20. The method according to claim 19, wherein the type of the BV candidate includes one of the following: Spatial BV candidate, History - based Motion Vector Prediction (HMVP) BV candidate, Paired BV candidate, Default BV candidate, or Other types of BV candidates.

21. The method according to claim 8, wherein if the BV candidate is Reconstructed - Re - ordered IBC (RR - IBC), the IBC - LIC mode is not used, or wherein if the BV candidate is RR - IBC, the IBC - LIC mode is used.

22. The method according to claim 21, wherein the original BV of the BV candidate is used to derive the IBC-LIC parameter.

23. The method according to claim 21, wherein the adjusted BV of the BV candidate according to the RR-IBC flip type is used to derive the IBC-LIC parameter.

24. The method according to claim 8, wherein a set of IBC-LIC parameters is derived.

25. The method according to claim 24, wherein the derived set of IBC-LIC parameters is used for at least one of the left template or the upper template.

26. The method according to claim 8, wherein multiple sets of IBC-LIC parameters are derived.

27. The method according to claim 26, wherein the first IBC-LIC parameter set in the multiple sets of IBC-LIC parameters is used for the left template, and / or wherein the second IBC-LIC parameter set in the multiple sets of IBC-LIC parameters is used for the upper template.

28. The method according to claim 8, wherein whether to apply the IBC-LIC mode to reorder the BV candidate list and / or the way of applying the IBC-LIC mode to reorder the BV candidate list depends on the codec tool using the BV candidate list.

29. The method according to claim 28, wherein if the codec tool is at least one of the following, the IBC-LIC mode is applied to the process of reordering the BV candidate list: IBC AMVP mode, IBC regular Merge mode, IBC TM Merge mode, or IBC-MBVD Merge mode.

30. The method according to claim 28, wherein if the codec tool is at least one of the following, the IBC-LIC mode is not applied to the process of reordering the BV candidate list: IBC AMVP mode, IBC regular Merge mode, IBC TM Merge mode, or IBC-MBVD Merge mode.

31. The method according to claim 1, wherein if RR-IBC is used, the IBC-LIC mode is used.

32. The method according to claim 31, wherein at least one of the position or shape of the template used for LIC depends on whether RR-IBC is applied.

33. The method according to claim 31, wherein the original BV not adjusted according to the RR-IBC flip type is used to derive the IBC-LIC parameter.

34. The method according to claim 31, wherein the adjusted BV according to the RR-IBC flip type is used to derive the IBC-LIC parameter.

35. The method according to claim 31, wherein the original template of the reference block is used to derive the IBC-LIC parameter.

36. The method according to claim 35, wherein the original template of the reference block is constrained in the IBC cache.

37. The method according to claim 35, wherein if the original template is not in the IBC cache, the IBC-LIC mode is not used.

38. The method according to claim 35, wherein if the original template is not in the IBC cache, the original template is filled with samples in the IBC cache, and the filled original template is used in the IBC-LIC mode.

39. The method according to claim 31, wherein the adjusted template of the reference block is used to derive IBC-LIC parameters.

40. The method according to claim 39, wherein the adjusted template of the reference block is constrained in the IBC cache.

41. The method according to claim 39, wherein the adjusted template of the reference block is adjusted according to the RR-IBC flip type.

42. The method according to claim 41, wherein if the RR-IBC flip type is horizontal, the adjusted left and upper templates of the reference template are used.

43. The method according to claim 41, wherein if the RR-IBC flip type is vertical, the adjusted left and upper templates of the reference template are used.

44. The method according to claim 39, wherein if the adjusted template is not in the IBC cache, the IBC-LIC mode is not used.

45. The method according to claim 39, wherein if the adjusted template is not in the IBC cache, the adjusted template is filled with samples in the IBC cache, and the subsequently filled template is used in the IBC-LIC mode.

46. The method according to claim 31, wherein the IBC-LIC mode is used together with the RR-IBC flip type.

47. The method according to claim 46, wherein the RR-IBC flip type is horizontal, or wherein the RR-IBC flip type is vertical.

48. The method according to any one of claims 1 to 47, wherein whether to apply the IBC-LIC mode and / or the way of applying the IBC-LIC mode depends on the codec information of the video unit, and wherein 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.

49. The method according to claim 48, wherein when the block size is less than or equal to a first threshold, the block is allowed to be coded and decoded using the IBC-LIC mode, wherein the block size is equal to W×H, and W and H represent the block width and block height of the block, respectively.

50. The method according to claim 49, wherein the first threshold is equal to one of 256, 512, 1024, 2048, or 4096.

51. The method according to claim 49, wherein the first threshold depends on whether the IBC AMVP mode or the IBCMerge mode is used.

52. The method according to claim 49, wherein the first threshold depends on the slice type or the picture type.

53. The method according to claim 48, wherein when the block size is greater than or equal to a second threshold, the block is allowed to be encoded and decoded using the IBC-LIC mode, where the block size is equal to W×H, and W and H respectively represent the block width and the block height of the block.

54. The method according to claim 53, wherein the second threshold is equal to one of 16, 32, 64, 128 or 256.

55. The method according to claim 53, wherein the second threshold depends on whether the IBC AMVP mode or the IBCMerge mode is used.

56. The method according to claim 53, wherein the second threshold depends on the slice type or the picture type.

57. The method according to any one of claims 48 to 53, wherein the block size refers to the luma block size.

58. The method according to claim 1, wherein the indication of the IBC-LIC mode is indicated based on a condition, or wherein the indication of the IBC-LIC mode is derived.

59. The method according to claim 58, wherein the condition includes at least one of the following: whether the target coding and decoding method is allowed; block dimension, block size, block depth, slice type, picture type, partition tree type, temporal layer identifier, block position, or color component.

60. The method according to claim 59, wherein when the block size is less than or equal to a third threshold, the indication of the IBC-LIC mode is not indicated, where the block size is equal to W×H, and W and H respectively represent the block width and the block height of the block.

61. The method according to claim 60, wherein the third threshold is equal to one of 256, 512, 1024, 2048 or 4096.

62. The method according to claim 60, wherein the third threshold depends on whether the IBC AMVP mode or the IBCMerge mode is used.

63. The method according to claim 60, wherein the third threshold depends on the slice type or the picture type.

64. The method according to claim 59, wherein when the block size is greater than or equal to a fourth threshold, the indication of the IBC-LIC mode is not indicated, where the block size is equal to W×H, and W and H respectively represent the block width and the block height of the block.

65. The method according to claim 64, wherein the fourth threshold is equal to one of 16, 32, 64, 128 or 256.

66. The method according to claim 64, wherein the fourth threshold depends on whether the IBC AMVP mode or the IBCMerge mode is used.

67. The method according to claim 64, wherein the fourth threshold depends on the slice type or the picture type.

68. The method according to any one of claims 59 to 67, wherein the block size refers to the luminance block size.

69. The method according to claim 58, wherein if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be the default value.

70. The method according to claim 69, wherein if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be false.

71. The method according to claim 69, wherein if the indication of the IBC-LIC mode is not indicated, the indication of the IBC-LIC mode is presumed to be true.

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

73. The method according to claim 72, wherein when the video unit is encoded or decoded using the IBC Merge mode, the indication of the IBC-LIC mode is not indicated.

74. The method according to claim 27, wherein whether a block is allowed to be encoded or decoded using the IBC-LIC mode depends on one or more syntax elements.

75. The method according to claim 74, wherein the one or more syntax elements are indicated as general constraint information.

76. The method according to claim 75, wherein when the syntax element indicating the general constraint on IBC-LIC is equal to a first value, the IBC-LIC mode is not allowed, or wherein when the syntax indicating the general constraint on IBC is equal to a second value, the IBC-LIC is not allowed.

77. The method according to claim 76, wherein the syntax element is gci_no_ibc_constraint_flag, and / or wherein the first value is 0 or 1, and / or wherein the second value is 0 or 1.

78. The method according to claim 74, wherein the one or more syntax elements are indicated at one of the following: Sequence header, Picture header, Sequence parameter set (SPS), Video parameter set (VPS), Dependency parameter set (DPS), Decoding capability information (DCI), Picture parameter set (PPS), Adaptive parameter set (APS), Slice header, or Slice group header.

79. The method according to any one of claims 1 to 78, wherein the video unit includes at least one of the following: Color component, Prediction block (PB), Transform block (TB), Codec block (CB), Prediction unit (PU), Transform unit (TU), Codec tree block (CTB), Codec unit (CU), Codec tree unit (CTU), CTU row, CTU group, Slice, Picture, Sub-picture, Block, Sub-region within a block, or Region containing more than one sample or pixel.

80. The method according to any one of claims 1 to 78, wherein an indication of whether and / or how the refined prediction samples of the video unit are derived by applying the IBC-LIC mode is indicated at one of the following: Sequence level, Group of pictures level, Picture level, Slice level, or Slice group level.

81. The method according to any one of claims 1 to 78, wherein an indication of whether and / or how the refined prediction samples of the video unit are derived by applying the IBC-LIC mode is indicated at one of the following: 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), Slice header, or Slice group header.

82. The method according to any one of claims 1 to 78, wherein an indication of whether and / or how the refined prediction samples of the video unit are derived by applying the IBC-LIC mode is indicated at one of the following: PB, TB, CB, PU, TU, CU, VPDU, CTU, CTU row, Slice, Picture, Sub-picture; or A region containing more than one sample or pixel.

83. The method according to any one of claims 1 to 78, wherein whether and / or how the refined prediction samples of the video unit are derived by applying the IBC-LIC mode is the transcoded information of the video unit, and wherein the transcoded information includes at least one of the following: Block size, Color format, Single-tree segmentation, Dual-tree segmentation, Color component, Slice type, or Picture type.

84. The method according to any one of claims 1 to 78, wherein the conversion includes encoding the video unit into the bitstream.

85. The method according to any one of claims 1 to 78, wherein the conversion includes decoding the video unit from the bitstream.

86. An apparatus for video processing, comprising a processor and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 85.

87. A non-transitory computer-readable storage medium storing instructions that cause a processor to perform the method according to any one of claims 1 to 85.

88. A non-transitory computer-readable recording medium storing a bitstream generated by a method executed by an apparatus for video processing for a video, wherein the method includes: Determining whether to apply an intra block copy (IBC) and local illumination compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; If it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit includes: Obtaining a prediction of the video unit by applying the IBC to the video unit; and Obtaining the refined prediction of the video unit by applying the LIC to the prediction; and generating the bitstream based on the refined prediction.

89. A method for storing a bitstream of video, comprising: Determining whether to apply an Intra Block Copy (IBC) and Local Illumination Compensation (LIC) (IBC-LIC) mode to a video unit for conversion between the video unit of the video and the bitstream of the video unit; If it is determined to apply the IBC-LIC mode to the video unit, deriving a refined prediction of the video unit by applying the IBC-LIC mode to the video unit, wherein deriving the refined prediction of the video unit comprises: Obtaining a prediction of the video unit by applying the IBC to the video unit; and Obtaining the refined prediction of the video unit by applying the LIC to the prediction; Generating the bitstream based on the refined prediction; and Storing the bitstream in a non-transitory computer-readable recording medium.

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