Abstract: Methods, apparatus, systems for video processing, including video encoding or video decoding are described. One example method includes performing a conversion between a video comprising a video picture that includes a video slice and a bitstream of the video. The bitstream conforms to a format rule specifying that, in case a slice type of the video slice is type P and temporal motion vector prediction is enabled, usage of reference picture resampling (RPR) for a reference picture in a collocated reference picture list is disabled. The reference picture is indicated by a reference index of a collocated picture of the video slice used for the temporal motion vector prediction.

Abstract: A method for video processing includes determining that a size of a residual block of a video is larger than a maximum block size allowed for a transform skip mode, in which, during a decoding operation, residual coefficients are decoded without performing an inverse transform operation; splitting, based on the size of a residual block, the residual block into multiple regions, wherein each region represents a portion of the residual block of a difference between a portion of a current video block and a prediction block corresponding to the portion of the current video block; and determining a reconstructed current video block from the residual block based on selectively performing the inverse transform operation according to an indicator that indicates the transform skip mode.

Abstract: Methods, systems and devices for implementing adaptive color transform (ACT) and block based delta pulse code modulation (BDPCM) during image/video encoding or decoding are described. An example method of video processing includes determining, for a conversion between a current video unit of a video that is a chroma video unit and a bitstream representation of the video, whether a block-based delta pulse code modulation (BDPCM) mode is available based on a rule, and performing the conversion based on the determining, wherein the rule is based on whether an adaptive color transform (ACT) mode is used for coding the current video unit and/or whether the BDPCM mode is used for coding a luma video unit corresponding to the current video unit.

Abstract: Methods and apparatus for processing of video are described. The processing may include video encoding, decoding or transcoding. One example video processing method includes performing a conversion between a video including a current picture including a current subpicture including a current slice and a bitstream of the video. The bitstream conforms to a format rule that disallows an active entry in a reference picture list of the current slice from including a first picture that precedes in a decoding order a second picture that includes a step-wise temporal sublayer access subpicture in response to conditions associated with at least the first picture and the current subpicture.

Abstract: A method includes performing a conversion between a video including at least one video picture and a bitstream of the video according to a rule, wherein the at least one video picture includes one or more slices and one or more subpictures, and wherein the rule specifies that an order of slice indices of the one or more slices in the at least one video picture is indicated responsive to a syntax element associated with the at least one picture indicative of whether a single slice is included per subpicture of the at least one video picture.

Abstract: A method includes performing a conversion between a current slice of a current picture of a video and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that a general constraint information syntax structure, which comprises one or more constraint flags indicating constraints on an explicit weighted prediction being enabled for slices of a set of pictures, is present.

Abstract: Methods, devices and systems for configuring different access units in scalable video coding are described. In one example aspect, a method of video processing include performing a conversion between a video including one or more pictures in one or more video layers and a bitstream of a video. The bitstream includes a coded video sequence that includes one or more access units. The bitstream conforms to a format rule that specifies that each access unit of the one or more access units that is a gradual decoding refresh access unit includes exactly one picture for each video layer present in the coded video sequence.

Abstract: Sub-table for history-based affine mode is described. In an exemplary aspect, a method for video processing includes deriving, deriving, for a conversion between a current block of video and a bitstream representation of the current block, an affine model for the current block based on affine related information, wherein the affine related information is stored in at least one first affine history motion vector prediction (HMVP) buffer of M first affine HMVP buffers or at least one affine sub-buffer of M affine sub-buffers (HB0, HB1, . . . HBM-1) into which a second affine HMVP buffer is divided, wherein the first affine HMVP buffer or affine HMVP sub-buffer being used to store affine related information of blocks coded prior the current block, M being an integer larger than 1; and performing the conversion by using the derived affine model.

Abstract: A method for processing a video includes maintaining one or more tables, wherein each table includes motion candidates derived from previously processed video blocks that are processed prior to a first video block of a video; deriving motion information for the first video block; applying refinement to the motion information when at least one decoder side motion vector derivation (DMVD) technologies is enabled; performing a conversion between a bitstream representation of the first video block and the first video block using the refined motion information; and determining, whether to use the refined motion information or un-refined motion information for updating one or more tables.

Abstract: Embodiments for video processing, including video coding, video decoding and video transcoding are described. One example method includes performing a conversion between a video having one or more layers having one or more video pictures having one or more subpictures and a bitstream of the video according to a rule, wherein the rule defines network abstraction layer (NAL) units to be extracted from a bitstream during a sub-bitstream extraction process to output a sub-bitstream, wherein the rule further specifies that one or more inputs to the sub-bitstream extraction process include a target output layer set (OLS) index (targetOlsIdx) that identifies an OLS index of a target OLS and is equal to an index to a list of OLSs specified by a video parameter set, and wherein the one or more inputs satisfy a set of conditions.

Abstract: A method includes performing a conversion between a video including a video picture and a bitstream of the video according to a rule, wherein the video picture including a subpicture, a tile, and a slice, and wherein the rule specifies that, due to the subpicture including the slice that is partitioned from the tile, the conversion is performed by refraining from counting a height of the subpicture using a number of tiles of the video picture.

Abstract: An exemplary method for visual media processing includes performing a conversion between a current video block of a visual media data and a bitstream representation of the visual media data in accordance with a conditional signalling rule, wherein the current video block is disabled from using an intra sub-block partitioning (ISP) split mode which divides the current video block into sub-blocks depending on dimensions of the current video block, wherein, in case that the conversion is associated with disabling use of the ISP split mode, the conditional signalling rule specifies selectively including in the bitstream representation a first syntax element indicating that a luma component of a sub-block of the current video block includes non-zero coefficient values, and further wherein the selectively including is based at least on one or more other syntax elements having non-zero coefficient values of one or more previous sub-blocks included in the bitstream 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 block of a video and a bitstream of the video according to a rule. The conversion is based on an adaptive motion vector difference resolution (AMVR) tool, and the rule specifies that selection of a context for a first bin within a bin string of a first syntax element that specifies the resolution of the motion vector difference associated with an AMVR shift is derived based on usage of a coding mode for the block.

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: Devices, systems and methods for the simplification of sub-block motion candidate lists for video coding are described. In a representative aspect, a method for video processing includes determining, during a conversion between a current block and a bitstream representation of the current block, a temporal motion vector prediction candidate for a sub-block of the current block. The temporal motion vector prediction candidate is completely determined based on K neighboring blocks of the current block, K being a positive integer. The method also includes performing the conversion based on the temporal motion vector prediction candidate for the sub-block.

Abstract: Methods, systems and apparatus for video processing are described. One example video processing method includes performing a conversion between a video including a video region and a bitstream of the video according to a rule, wherein the rule specifies that an adaptive loop filtering operation is allowed for the video region in response to an absence of one or more adaptation parameter set (APS) network abstraction layer (NAL) units that include adaptive loop filtering data.

Abstract: Examples of video encoding methods and apparatus and video decoding methods and apparatus are described. An example method of video processing includes performing a conversion between a video and a bitstream of the video according to a rule, wherein the bitstream includes network abstraction layer (NAL) units for multiple video layers according to a rule; wherein the rule defines that a sub-bitstream extraction process to generate an output bitstream comprising an output layer set (OLS) includes one or more operations that are selectively performed responsive to the following conditions: (1) a list of NAL unit header layer identifier values in the OLS does not includes all values of NAL unit header layer identifiers in all video coding layer (VCL) NAL units in the bitstream, and (2) the output bitstream containing a supplemental enhancement information (SEI) NAL unit that contains a scalable-nesting SEI message.

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 constraints on values of one or more first syntax elements in an adaptation parameter set are defined based on semantics of second syntax elements in a picture header and/or a slice header if a picture or a slice referring to the adaptation parameter set.

Abstract: A method includes making a determination, according to a rule, about whether a height of a subpicture of a video picture of a video is less than a height of a tile row of the video picture; and performing, using the determination, a conversion between the video and a bitstream of the video.

Abstract: Techniques for video encoding and decoding are described. A method of video processing is disclosed. The method includes, determining, based on a video characteristic of a first video block, an enabling or disabling of a pruning process for a table updating process; updating one or multiple tables, based on the determination and motion information of the first video block, the one or multiple motion tables being History-based Motion Vector Prediction HMVP (HMVP) tables; and performing a conversion between a subsequent video block of the video and bitstream representation of the subsequent video block based on the updated tables.