Abstract: A method for processing a video includes performing a conversion between a current block of visual media data and a corresponding coded representation of the visual media data. The conversion of the current block includes determining whether a use of one or both of a bi-directional optical flow (BIO) technique or a decoder-side motion vector refinement (DMVR) technique to the current block is enabled or disabled. Determining the use of the BIO technique or the DMVR technique is based on a cost criterion associated with the current block.

Abstract: In an exemplary aspect, a method for visual media processing includes identifying a boundary at a vertical edge and/or a horizontal edge of two video blocks; calculating a boundary strength of a filter based on at least one of the two video blocks crossing a vertical edge or a horizontal edge is coded using a combined intra-inter prediction (CIIP) mode; deciding whether to turn on or off the filter; selecting a strength of the filter in case the filter is turned on; and performing, based on the selecting, a deblocking filter (DB) process to the video blocks.

Abstract: Devices, systems and methods related to digital video coding, and specifically, to signaling of slice types in video picture headers are described. One example method of video processing includes performing a conversion between a video including one or more video pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that for a video picture of the one or more video pictures having all slices coded as I slices, P slice and B slice related syntax elements are omitted from a picture header for the video picture.

Abstract: A method of video processing includes performing a conversion between a current video block of a second color component of a video and a bitstream of the video using a cross-component prediction with multiple-parameter model (CCPMPM) in which samples of the current video block are predictively coded in the bitstream using a linear combination of samples of a first color component multiplied by linear coefficients and/or one or more offsets. The bitstream conforms to a format rule. The linear coefficients of the CCPMPM are determined using a first rule. The samples of the first color component are determined using a second rule.

Abstract: Disclosed are a shield tunnel segment structure and a construction method thereof. The shield tunnel segment structure includes segment blocks sequentially spliced in a circumferential direction. Each segment block forms a closed annular segment structure, and outer diameters of adjacent annular segment structures gradually increase in an axial direction. At least two adjacent segment blocks of the same annular segment structure form an annular inner groove, and at least one segment block of the adjacent annular segment structures is provided with an inner bump which matches the annular inner groove. At least two adjacent segment blocks of the same annular segment structure form an annular outer groove, and at least one segment block of the adjacent annular segment structures is provided with an outer bump which matches the annular outer groove. The annular outer grooves and the annular inner grooves are staggered in the circumferential direction.

Abstract: In one example aspect, a method of video processing includes performing a conversion between a current block in a video unit of a video and a coded representation 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, a predictor palette is used for predicting the palette of representative sample values. The predictor palette is re-initialized upon a condition being satisfied. The condition is satisfied in case the video unit is a first video unit in a video unit row and a syntax element is included in the coded representation indicating that a wavefront parallel processing is enabled for the video unit.

Abstract: Embodiments for video encoding and video decoding are described. One example method includes performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies that only one of two conditions is true when a number of subpictures minus 1 indicated by a first syntax element in a sequence parameter set is greater than zero and when a current subpicture with a subpicture index subpicIdx of a first video picture of the video has a second syntax element in the sequence parameter set indicates that a subpicture with the subpicture index subpicIdx of each video picture of the video in a coded layer video sequence is treated as a video picture in a decoding process that excludes an in-loop filtering operation.

Abstract: An example method of video processing includes performing a conversion between a picture of a video and a bitstream representation of the video. The picture includes one or more sub-pictures, and the bitstream representation conforms to a format rule that specifies that a length of a syntax element is equal to Ceil(Log 2(SS)) bits. SS is greater than 0, and the syntax element indicating a horizontal or a vertical position of a top-left corner of a coding tree unit of a sub-picture of the picture.

Abstract: A method includes performing a conversion between a video including a video picture including one or more tiles and a bitstream of the video. The video picture refers to a picture parameter set, and the picture parameter set conforms to a format rule specifying that the picture parameter set includes a list of column widths for N tile columns, where N is an integer. An (N?1)-th tile column exists in the video picture and the (N?1)-th tile column has a width that is equal to an (N?1)-th entry in a list of explicitly included tile column widths plus one number of coding tree blocks.

Abstract: Video coding and decoding methods are described. An example method includes performing a conversion between a current video block of a video and a bitstream representation of the current video block by determining a first intra coding mode to be stored which is associated with the current video block using a differential coding mode, where the first intra coding mode associated with the current video block is determined according to a second prediction mode used by the differential coding mode, and where, in the differential coding mode, a difference between a quantized residual of an intra prediction of the current video block and a prediction of the quantized residual is represented in the bitstream representation for the current video block using a differential pulse coding modulation (DPCM) representation.

Abstract: Systems, methods and apparatus for video processing are described. The video processing may include video encoding, video decoding, or video transcoding. One example method of video processing includes performing a conversion between a video and a bitstream of the video according to a format rule. The format rule specifies that a first field at a sequence level or a picture level or a slice level controls a value of a second field in an adaptation parameter set.

Abstract: Devices, systems and methods for digital video coding, which includes matrix-based intra prediction methods for video coding, are described. In one aspect, a method for video processing includes performing a conversion between a current video block of a video and a bitstream representation of the current video block using a matrix based intra prediction (MIP) mode, where the conversion includes performing the upsampling operation in which the final prediction block is determined by using a reduced prediction block of the current video block and by using reconstructed neighboring samples of the current video block according to a rule, and where the reduced prediction block is obtained by performing the matrix vector multiplication operation on reduced boundary samples of the current video block.

Abstract: A method of visual media processing includes determining, for a conversion between a current video block of visual media data and a bitstream representation of the current video block, a buffer that stores reference samples for prediction in an intra block copy mode; for a sample spatially located at location of the current video block relative to an upper-left position of a coding tree unit including the current video block and having a block vector, computing a corresponding reference in the buffer at a reference location, wherein the reference location is determined using the block vector and the location; and upon determining that the reference location lies outside the buffer, re-computing the reference location based at least in part on a location of the current video block relative to the coding tree unit including the current video block.

Abstract: Techniques for implementing video processing techniques are described. In one example implementation, a method of video processing includes determining, for a conversion between a current block of a video coded using a combined inter and intra prediction (CIIP) coding technique and a bitstream representation of the video, an intra-prediction mode of the current block independently from an intra-prediction mode of a neighboring block. The CIIP coding technique uses an intermedia inter prediction value and an intermedia intra prediction value to derive a final prediction value of the current block. The method also includes performing the conversion based on the determining.

Abstract: Difference calculation based on partial position is described. In a representative aspect, a method of video processing comprising: calculating, during a conversion between a current block of video and a bitstream representation of the current block, differences between two reference blocks associated with the current block or differences between two reference sub-blocks associated with a sub-block within the current block based on representative positions of the reference blocks or representative positions of the reference sub-blocks; and performing the conversion based on the differences.

Abstract: An example method of video processing includes determining, for a conversion between a block of a first sub-picture of a video and a bitstream representation of the video, whether to apply a deblocking process across an edge between the block and a neighboring block of a second sub-picture based on whether a loop filtering process is allowed across subpicture boundaries. The method also includes performing the conversion based on the determining.

Abstract: A method for visual media processing includes performing a conversion between a current video unit of a visual media data and a bitstream representation of the current video unit. The bitstream representation is configured according to a format rule. The format rule specifies a level of a video segment at which one or more syntax elements indicative of a scaling factor by which a chroma residual is scaled for coding the current video unit is selectively included in the bitstream representation.

Abstract: A method of video processing is provided to include: performing a conversion between a video including one or more video regions including one or more luma blocks and one or more chroma blocks and a coded representation of the video according to a rule; wherein the rule specifies that a chroma block from the one or more chroma blocks having a size M×N is disallowed to be represented in the coded representation using an intra mode or an intra block copy mode, wherein M and N are integers that indicate a width and a height of the chroma block, respectively; wherein the intra mode includes encoding the chroma block based on previously encoded or reconstructed video blocks, and wherein the intra block copy mode includes encoding the chroma block using at least a block vector pointing to a video frame containing a video region.

Abstract: A method for implementing an adaptive color transform (ACT) during image/video encoding and decoding, includes determining, for a conversion between a video including a block and a bitstream of the video, that a size of the block is greater than a maximum allowed size for an ACT mode, and performing, based on the determining, the conversion, wherein, in response to the size of the block being greater than the maximum allowed size for the ACT mode, the block is partitioned into multiple sub-blocks, and wherein each of the multiple sub-blocks share a same prediction mode, and the ACT mode is enabled at a sub-block level.

Abstract: A method of video processing is described. The method includes determining, for a conversion between a current video block of a video and a coded representation of the video, whether a certain partitioning scheme is allowed for the current video block according to a rule that depends on a coding mode type used for representing the current video block in the coded representation and a dimension of the current video block; and performing the conversion based on the determining.