Abstract: A video processing method includes performing a conversion between a video comprising a video unit and a bitstream of the video according to a rule. The rule specifies whether or how to include, in an adaptation parameter set (APS), information related to a scaling list of the video is based on a first syntax element. The first syntax element indicates whether the APS includes chroma component related syntax elements and is independent of one or more syntax elements in a sequence parameter set (SPS).

Abstract: Methods, systems, apparatus for video processing are described. A method for processing video includes performing a conversion between a video and a bitstream of the video according to a format rule, and wherein the format rule specifies whether a syntax element in a sequence parameter set (SPS) based on a value of a general constraint flag.

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 including one or more layers and a bitstream of the video according to a rule, wherein the rule specifies, in a process of sub-bitstream extraction to output an output sub-bitstream, whether to generate non-scalable nested supplementary enhancement information (SEI) messages by extracting scalable-nested SEI messages from a scalable nesting SEI message based on a first flag indicating whether the SEI message applies to specific output layer sets (OLSs) and a second flag indicating whether the SEI message applies to all subpictures or only to specific subpictures.

Abstract: Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a subpicture in a video picture of a video and a bitstream of the video according to a rule. The rule specifies that, in in case a subpicture is treated as a video picture for the conversion, a cross-layer alignment restriction is applied to less than all of the multiple layers including a current layer that includes the subpicture and a subset of layers associated with the current layer.

Abstract: Methods, systems, and devices for picture header constraints for multi-layer coding are described. An example method of video processing includes performing a conversion between a video including one or more pictures and a bitstream of the video. The bitstream conforms to a format rule. The format rule specifies a constraint on a value of a first syntax element that specifies whether a second syntax element is present in a picture header syntax structure of a current picture. The second syntax element specifies a value of a picture order count (POC) most significant bit (MSB) cycle of the current picture.

Abstract: Systems, methods and apparatus for processing visual media data are described. One example method includes performing a conversion between visual media data and a visual media file that includes one or more tracks that store one or more bitstreams of the visual media data according to a format rule; wherein the visual media file includes a base track that references one or more subpicture tracks, and wherein the format rule specifies an order of non-VCL (video coding layer) NAL (network abstraction layer) units in a sample of the base track in reconstructing a video unit from the sample of the base track and samples in the one or more subpicture tracks.

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. At least one of the one or more parameter sets of the bitstream includes a general syntax structure including timing and hypothetical reference decoder (HRD) parameters. The rule specifies that a first syntax flag is not included in the general syntax structure in response to (1) a second syntax flag specifying that network abstraction layer (NAL) HRD parameters are not present in the general syntax structure, and (2) a third syntax flag specifying that video coding layer (VCL) HRD parameters are not present in the general syntax structure, where the first syntax flag specifies that same picture-level timing information applies to all output layer sets in the bitstream.

Abstract: A method of video processing includes performing a conversion between a video including one or more scalable video layers and a bitstream of the video. The video includes one or more video pictures including one or more slices. The bitstream conforms to a format rule. The format rule specifies that a value of a field indicative of a slice type of a slice is set to indicate a type of intra slice in case that a corresponding network abstraction layer unit type is in a predetermined range and that a corresponding video layer flag indicates that a video layer containing the slice does not use inter-layer prediction.

Abstract: Devices, systems and methods for specifying the syntax and semantics of the decoding parameter set (DPS) are described. One example method of video processing includes determining, for a conversion between a video and a bitstream of the video, that each output layer set (OLS) in a coded video sequence (CVS) in the bitstream conforms to at least one profile-tier-level (PTL) syntax structure included in a data structure associated with decoding parameter semantics in the bitstream, and performing, based on the determining, the conversion, wherein the PTL syntax structure indicates a profile, a tier, and a level of the bitstream.

Abstract: A method of processing video data includes performing a conversion between a video and a bitstream of the video. The bitstream comprises one or more layers comprising one or more pictures comprising one or more subpictures according to a rule which specifies that, responsive to a condition, a selective processing of a first supplemental enhancement information network abstraction layer, SEI NAL, unit of a target output subpicture sub-bitstream that is extracted during a subpicture sub-bitstream extraction process.

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 including one or more pictures and a bitstream of the video according to a format rule. The format rule specifies that a first syntax element that indicates whether motion vector difference for a particular reference picture list (RPL) is indicated is conditionally included in the bitstream based on (i) whether a second syntax element indicating whether an RPL information is included in a picture header and/or (ii) a number of reference pictures in the particular RPL in case that the RPL information is present in the picture header.

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 current picture of a video and a bitstream of the video according to a rule. The rule specifies that the current picture is a recovery point picture in response to the current picture being a Gradual Decoding Refresh (GDR) picture with a recovery Picture Order Count (POC) value of 0. The recovery POC count specifies a recovery point of decoded pictures in an output order.

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: Methods, apparatus and systems for processing video are described. One example method includes performing a conversion between a video comprising a video unit and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that a first syntax element indicating whether an in-loop filtering operation is performed across tile boundaries is selectively included in the bitstream responsive to whether or how the video unit is partitioned into tiles.

Abstract: A method of video processing, including performing a conversion between a video unit of a video and a bitstream of the video according to a rule, wherein the rule specifies that whether a cross-component adaptive loop filter (CC-ALF) mode and an adaptive loop filter (ALF) mode are enabled for coding the video unit are indicated in the bitstream in a mutually independent manner.

Abstract: Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a video including a video unit and a bitstream of the video according to a rule. The rule specifies whether a transform skip residual coding operation is enabled for the video unit. One or more syntax elements are included in the bitstream at a video segment level indicative of whether the transform skip residual coding operation is enabled for the video unit.

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, in which 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, 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 the one or more inputs satisfy a set of conditions.

Abstract: A video processing method includes performing a conversion between a video having one or more video layers comprising a current picture comprising a current slice and a bitstream of the video according to a rule. The rule specifies a condition under which a reference picture list for the current slice is disallowed to have an active entry that refers to a picture that precedes, in a decoding order or an output order, an intra random access point picture associated with the current picture.

Abstract: Methods, systems and devices for implementing constraints used in video encoding and video decoding are described. An example method of video processing includes performing a conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the bitstream is organized into a plurality of access units (AUs), AU 0 to AU n, based on a format rule, where n is a positive integer, wherein the format rule specifies a relationship between removal times of each of the plurality of AUs from a coded picture buffer (CPB) during decoding and a number of slices in the each of the plurality of AUs.

Abstract: Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a subpicture in a video picture of a video and a bitstream of the video according to a rule. The rule specifies that multiple syntax elements are used to specify usage of a reference picture resampling tool.