Abstract: Embodiments of the present disclosure provide a solution for video processing. A method for video processing is proposed. The method comprises: determining, for a conversion between a current block of a video and a bitstream of the video, that a first prediction mode is applied to the current block, deriving, in the first prediction mode, prediction samples of the current block based on reference values in a virtual buffer that are determined by a block vector for the current block; performing the conversion based on the prediction samples; determining a set of blocks from a plurality of blocks of the same video region based on coded information of the plurality of blocks, the plurality of blocks being coded before the current block; and updating the virtual buffer based on the set of blocks.

Abstract: A method of visual media processing video, includes determining that palette mode is to be used for processing a first portion of a video block and intra block copy (IBC) mode is to be used for processing a second portion of the video block, and performing further processing of the first portion of the video block using the palette mode and the second portion of the video using the IBC mode, wherein indications of the first portion of the video block processed using the palette mode and indications of the second portion of the video block processed using the IBC mode are included in a palette index identifying the first portion of the video block and the second portion of the video block.

Abstract: An example method of video processing includes determining, for a conversion between a current block of a video and a bitstream representation of the video, whether to enable usage of a chroma quantization parameter (QP) offset for the current block according to a syntax element at a level of a video unit. The video unit includes the current block and a second block of the video. The method also includes performing the conversion based on the determining.

Abstract: Methods and apparatus for video processing are disclosed. The processing may include video encoding, video decoding, or video transcoding. One example method includes performing a conversion between a current block of a video and a bitstream of the video. The bitstream conforms to a rule that specifies that a context index offset is used for including a first sign flag of a first coefficient in the bitstream. The rule specifies that a value of the context index offset is based on whether a first coding mode is applied on the current block in the bitstream.

Abstract: In one example aspect, a method of video processing includes performing a conversion between a current block of a video and a bitstream of the video using a palette mode in which a palette of representative sample values is used for coding the current block. During the conversion, one or multiple predictor palettes are used for predicting the palette of representative sample values, and wherein updating of the one or multiple predictor palettes after the conversion of the current block is disabled according to a rule based on a characteristic of the current block.

Abstract: Methods, systems, and devices for performing entropy coding for a palette escape symbol in palette mode coding and decoding are described. An example method for video processing includes performing a conversion between a video having one or more video regions including a current video block and a bitstream representation of the video, wherein the bitstream representation conforms to a format rule that the current video block is coded using a palette mode coding tool, wherein a binarization of an escape symbol for the current video block uses an exponential-Golomb (EG) code of order K, wherein K is a non-negative integer that is unequal to three, and wherein the palette mode coding tool represents the current video block using a palette of representative color values and wherein the escape symbol is used for a sample of the current video block coded without using the representative color values.

Abstract: Systems and methods for performing motion vector prediction for video coding are disclosed. A motion vector predictor is determined based at least in part on motion information associated with a selected motion vector predictor origin and offset values corresponding to a selected sampling point. The sampling point is specified according to a set of direction and distance on a sampling map for the motion vector predictor origin.

Abstract: Method of processing video data is disclosed. A method for video processing includes dividing, for a conversion between a block of a video and a bitstream of the block, syntax elements associated with the block into different groups of syntax elements; applying controls on the different groups of syntax elements separately; and performing the conversion based on the controls.

Abstract: Devices, systems, and methods for palette mode coding are described. An exemplary method for video processing includes determining, for a conversion between a block of a video region in a video and a bitstream representation of the video, a prediction mode based on one or more allowed prediction modes that include at least a palette mode of the block. An indication of usage of the palette mode is determined according to the prediction mode. The method also includes performing the conversion based on the one or more allowed prediction modes.

Abstract: A method of video processing includes making a determination for a conversion between a video region of a video and a bitstream representation of the video to use a cross-component adaptive loop filtering (CC-ALF) tool for refining chroma samples values using luma sample values; and performing the conversion based on the determination, wherein the refining includes correcting the chroma sample values using a final refinement that is a further refinement of a first refinement value determined by selectively filtering the luma sample values.

Abstract: Method, device, apparatus, and computer-readable storage medium to determine whether video block is a fractional boundary video block (See paragraph and FIG. 7.) and to partition the fractional boundary video block into inferred partitions using a subset of available partition modes (See paragraph and FIG. 8.) are disclosed.

Abstract: A method of video processing is described. The method includes performing a conversion between a current video block of a video and a coded representation of the current video block according to a rule, wherein the rule specifies that, due to use of an identity transform coding tool for representing the current video block into the coded representation, a syntax field indicative of a quantization parameter used for decoding the current video block is included such that a value of the quantization parameter is modified according to a rule, wherein the identity transform coding tool allows coefficient values at a transform domain of the current block to be same as values of a residual block of the current video block.

Abstract: Interaction between screen content coding tools and motion information is disclosed. A method of video processing includes modifying, for a conversion between a block of a video and a bitstream representation of the block, at least one of motion information associated with the block which is coded with intra block copy (IBC) mode; and performing the conversion based on the modified motion information.

Abstract: Systems and methods for performing motion vector prediction for video coding are disclosed. A motion vector predictor is determined based at least in part on motion information associated with a selected motion vector predictor origin and offset values corresponding to a selected sampling point. The sampling point is specified according to a set of direction and distance on a sampling map for the motion vector predictor origin.

Abstract: Devices, systems and methods for video processing are described. An example method for video processing includes determining, for a conversion between a current block of a video and a bitstream representation of the video, a number of intra-coded neighboring blocks of the current block for a combined inter and intra prediction mode according to a rule that specifies a manner of treating a block coded using a palette coding mode in counting the number of intra-coded neighboring blocks for the combined inter and intra prediction mode. The method also includes performing the conversion based on the determining.

Abstract: A method for video processing includes applying a sub-block residual coding scheme to a current video block, wherein the residual of the current video block is split into a plurality of sub-blocks each having a size of M*N, determining at least one sub-block with non-zero coefficients based on characteristic associated with each of the plurality of sub-blocks; coding the residue of the current video block based on the derived at least one sub-block with non-zero coefficients.

Abstract: Restrictions on number of context coded bins are described. A method for video processing includes applying, for a conversion between a video and a bitstream representation of the video, control on maximum number of context coded bins per predetermined unit which is associated with the video; and performing the conversion based on the control.

Abstract: Interaction between screen content coding tools and motion information is disclosed. A method of video processing includes modifying, for a conversion between a block of a video and a bitstream representation of the block, at least one of motion information associated with the block which is coded with intra block copy (IBC) mode; and performing the conversion based on the modified motion information.

Abstract: Chroma deblocking harmonization for video coding are described. In an exemplary aspect, a method for video processing includes deriving, for a conversion between a video processing unit of the video and a bitstream representation of the video processing unit, at least one decision result associated with decisions in a chroma deblocking filter decision process of the video processing unit; applying a same decision result from the at least one decision result for all chroma components of the video processing unit; and performing the conversion based on the same decision result.

Abstract: A video coding device may be configured to perform video coding according to one or more of the techniques described herein. In one example, a method of partitioning video data for video coding, comprises receiving a video block including sample values, and partitioning the sample values according to the following set of partitioning modes: quadtree, horizontal or vertical symmetric binary tree, horizontal or vertical asymmetric binary tree, and horizontal or vertical triple tree.