Abstract: An example method of video processing includes performing a conversion between a block of a chroma component of a video and a bitstream representation of the video. During the conversion, a deblocking filter process is applied to at least some samples along an edge of the block, and wherein chroma quantization parameter (QP) offsets are added to outputs from a chroma QP table to determine parameters for the deblocking filter process.

Abstract: History-based affine parameters inheritance is described. In an exemplary aspect, a method for video processing includes deriving, for a conversion between a current block of video and a bitstream representation of the current block, affine related information associated with an affine model to be used by the current block based on affine related information associated with an affine model used by a first block stored in a buffer, wherein the first block is affine coded prior to the current block; and performing the conversion by using the derived affine related information.

Abstract: Video coding and decoding methods are described. An example method includes determining, based on an applicability rule, that a differential coding mode is applicable to a conversion between a chroma video block of a video and a bitstream representation of the chroma video block, and performing, based on the determining, the conversion between the chroma video block and the bitstream representation of the chroma video block using the differential coding mode, where the chroma video block is represented in the bitstream representation using a difference between a quantized residual of an intra prediction of the chroma video block and a prediction of the quantized residual in the differential coding mode, where the intra prediction is performed in a first direction and the prediction of the quantized residual is performed in a second direction, and where the difference is represented using a differential pulse coding modulation (DPCM) representation.

Abstract: Methods, systems, and devices for coefficient scaling for high-precision image and video coding are described. An example method of video processing includes performing a conversion between a current block of a video and a bitstream representation of the video according to a rule. The rule specifies that the conversion includes during encoding, skipping applying a forward transform to residual coefficients of the current block prior to including in the bitstream representation, or during decoding, reconstructing residual coefficients of the current block from the bitstream representation without applying an inverse transform. The rule further specifies that a scale factor is applied to the residual coefficients independent of a size of the current 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: Non-transform blocks of video content may be coded by selectively changing a scanning order. In some implementations, an encoder or decoder may perform a scanning process on a block according to a scanning order. When the block has not been transformed, the encoder or decoder may selectively change the scanning order to a different order. For example, if the block is associated with a particular type of prediction, the scanning order may be changed to a different order. In another example, if the non-transform block has a size that is smaller than a predetermined size, the scanning order may be changed to a different order.

Abstract: Devices, systems and methods for coefficient coding in transform skip mode are described. An exemplary method for visual media processing includes: for encoding a current video block in a video region of a visual media data into a bitstream representation of the visual media data, identifying usage of a coding mode and/or an intra prediction mode and/or a set of allowable intra prediction modes; and upon identifying the usage, making a decision of whether to include or exclude, in the bitstream representation, a syntax element indicative of selectively applying a transform skip mode to the current video block, wherein, in the transform skip mode, a residual of a prediction error between the current video block and a reference video block is represented in the bitstream representation of the visual media data without applying a transformation.

Abstract: A method of video processing includes performing a conversion between a video unit of a video and a coded representation of the video using at least a video picture. Only one of a sub-picture coding mode or a resolution-changing coding mode is enabled for the video unit. The sub-picture coding mode is a mode in which the video picture is divided into multiple sub-pictures, and the resolution-changing coding mode is a mode in which a resolution of the video picture is adjusted during the conversion.

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: Devices, systems, and methods for palette mode coding are described. An exemplary method for video processing includes performing a conversion between a block of a video and a bitstream representation of the video. The bitstream representation is processed according to a format rule that specifies a first indication of usage of a palette mode and a second indication of usage of an intra block copy (IBC) mode are signaled dependent of each other.

Abstract: Techniques for video processing, including video coding, video decoding and video transcoding are described. One example method includes performing a conversion between a video picture that includes one or more tiles and one or more rectangular slices and a bitstream of the video according to a rule. The rule specifies that, for iteratively determining information about the one or more rectangular slices, a variable indicating a tile index is updated only for slices having indices that are smaller than a value equal to a number of slices in the video picture minus 1.

Abstract: Innovations in the area of prediction of block vector (“By”) values improve encoding or decoding of blocks using intra block copy (“BC”) prediction. For example, some of the innovations relate to use of a default BV predictor with a non-zero value. Other innovations relate to use of a selected one of multiple BV predictor candidates for a current block. Still other innovations relate to use of a skip mode in which a current intra-BC-predicted block uses a predicted BV value.

Abstract: A method of video processing includes determining a refined prediction sample P?(x,y) at a position (x,y) in a video block by modifying a prediction sample P(x,y) at the position (x,y) with a first gradient component Gx(x, y) in a first direction estimated at the position (x,y) and a second gradient component Gy(x, y) in a second direction estimated at the position (x,y) and a first motion displacement Vx(x,y) estimated for the position (x,y) and a second motion displacement Vy(x,y) estimated for the position (x,y), where x and y are integer numbers, and performing a conversion between the video block and a bitstream representation of the video block using a reconstructed sample value Rec(x,y) at the position (x,y) that is obtained based on the refined prediction sample P?(x,y) and a residue sample value Res(x,y).

Abstract: A method of video processing is described. The method includes: deriving, for a conversion between a current block of a video and a coded representation of the video, a prediction block for the current block that is determined according to a tool in which weights are used to determine a weighted sum of two initial prediction blocks used to determine the prediction block; and performing the conversion using the prediction block; wherein the deriving includes: applying the weights to two intermediate prediction samples that respectively belong to the two initial prediction blocks to derive a final prediction sample; and performing a right shift operation for the final prediction sample, wherein the right shift operation is pbSample>> (shift1+3)), wherein pbSample represents the final prediction sample, shift1 is set equal to Max(2, 14?bitDepth); and determining the prediction block based on the final prediction sample.

Abstract: An example method of video processing includes determining, for a conversion between a block of a chroma component of a video and a bitstream representation of the video, whether or how to apply a filtering process to an edge of the block based on a first quantization information for a first video region comprising samples on one side of the edge and/or a second quantization information for a second video region comprising samples on the other side of the edge according to a rule that is based on a coding mode applicable to the block for coding the samples on the one side or the samples on the other side of the edge. The rule specifies that multiple QP offsets at different video unit levels are used to determine the first quantization information or the second quantization information. The method also includes performing the conversion based on the determining.

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: 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: 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: 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: 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.