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, wherein the bitstream includes one or more pictures including one or more subpictures according to a rule, and wherein the rule specifies that, responsive to a condition, a rewriting operation is performed on referenced one or more sequence parameter sets during a subpicture sub-bitstream extraction process by which a target output sub-bitstream is extracted from the bitstream.

Abstract: Methods, systems, and devices for signaling of general constraint information 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 according to a rule. The rule specifies that a syntax structure in a profile-tier-level syntax structure is after a syntax element. The syntax structure includes information related to general constraint information (GCI) for the bitstream. The syntax element indicates a level to which an output layer set associated with the profile-tier-level syntax structure conforms.

Abstract: This application provides a media data processing method and apparatus. A media processing device receives a media stream. The media stream includes media data recorded at a plurality of viewpoints. The device obtains metadata information of the media stream. The metadata information includes viewpoint identification information of the viewpoints. The device displays media data of a first viewpoint based on the viewpoint identification information. The device also displays indications of other viewpoints when displaying the media data of the first viewpoint, so that a user of the device can switch to display media data of other viewpoints.

Abstract: A method of decoding a coded video bitstream implemented by a video decoder is disclosed. The method includes determining that a coded video sequence (CVS) of the coded video bitstream includes a video coding layer (VCL) network abstraction layer (NAL) unit having a gradual decoding refresh (GDR) network abstraction layer (NAL) unit type (GDR_NUT), the VCL NAL unit having the GDR_NUT containing a GDR picture; initiating decoding of the CVS at the GDR picture; and generating an image according to the CVS as decoded. A corresponding method of encoding is also disclosed.

Abstract: Several techniques for video encoding and video decoding are described. An example method of processing video data includes performing a conversion between a video and a bitstream of the video, wherein the conversion is performed according to a format rule that specifies that a supplemental enhancement information network abstraction layer unit includes a network abstraction layer unit type equal to a prefix supplemental enhancement information network abstraction layer unit type in response to the supplemental enhancement information network abstraction layer unit including a scalable nesting supplemental enhancement information message that includes a supplemental enhancement information message not associated with a particular payload type.

Abstract: Methods, systems, apparatus for video processing are described. The processing may include encoding, decoding or transcoding. One example video processing method includes performing a conversion between a video and a bitstream of the video according to a rule, and wherein the rule specifies that a syntax element is included in a profile, tier, level information syntax structure to indicate whether one or more general constraint information syntax elements are included in a general constraint information syntax structure and/or whether the general constraint information syntax structure is included in the profile, tier, level information syntax structure.

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 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: 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, wherein the rule specifies whether a transform skip residual coding operation is enabled for the video unit, and wherein 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: 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, wherein the bitstream comprises one or more output layer sets comprising one or more video layers according to a rule, wherein the rule specifies a particular decoding order between a subpicture level information (SLI) supplemental enhancement information (SEI) message and a buffering period (BP) SEI message that apply to a particular output layer set, responsive to a condition that the SLI SEI message and the BP SEI message are included in an access unit.

Abstract: Methods, systems and apparatus for video processing are described. One example video processing method includes performing a conversion between a video comprising a video block and a bitstream of the video according to a rule, wherein the video block is a coding tree node that includes one or more coding units, and wherein the rule specifies that a coded information of the video block is indicative of whether a coding mode is enabled for the one or more coding units of the video block.

Abstract: A method of processing video data includes performing a conversion between a video and a bitstream of the video.

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 responsive to a picture being referred to by an inter-layer reference picture (ILRP) entry in a reference picture list of a slice of the current picture, the picture is allowed to have a gradual decoding refresh (GDR) type and a syntax element specifying a recovery point of the picture in an output order is 0.

Abstract: Methods, systems and devices for using end of sequence indications are described. An example method of video processing includes performing a conversion between a video and a bitstream of the video, wherein the bitstream includes multiple layers in multiple access units, AUs, including one or more pictures according to a format rule, wherein the format rule specifies that, responsive to an end of sequence (EOS) network abstraction layer (NAL) unit for a first layer being present in a first access unit (AU) in the bitstream, a subsequent picture of each of one or more higher layers of the first layer in an AU following the first AU in the bitstream is a coded layer video sequence start (CLVSS) picture.

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: Several embodiments for video encoding and video decoding are described. An example method of processing video data includes performing a conversion between a video comprising one or more subpictures and a bitstream of the video, wherein one or more supplemental enhancement information messages that have filler payloads are processed during the conversion according to a format rule, and wherein the format rule disallows the one or more supplemental enhancement information messages having filler payloads to be in a scalable nesting supplemental enhancement information message.

Abstract: A method of video data processing includes performing a conversion between a video and a bitstream of the video. The bitstream comprises multiple layers comprising one or more subpictures according to a rule which specifies that, during a subpicture sub-bitstream extraction process by which an output bitstream is extracted from the bitstream, a supplemental enhancement information network abstraction layer unit, SEI NAL unit, that includes a scalable nested SEI message that is not applicable to the output bitstream is omitted in the output bitstream.

Abstract: Methods, systems, and devices for picture output ordering constraints in video bitstreams 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 according to a rule, wherein the rule specifies that the bitstream includes at least a first picture that is output, wherein the first picture is in an output layer, wherein the first picture includes a syntax element equaling one, and wherein the syntax element affects a decoded picture output and a removal process associated with a hypothetical reference decoder (HRD).

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: A video coding mechanism is disclosed. The mechanism includes partitioning a picture into a plurality of tiles. A number of the tiles are included in a tile group. The mechanism determines whether the tile group is a raster scan tile group or a rectangular tile group. The number of tiles in the tile group is determined based on whether the tile group is the raster scan tile group or the rectangular tile group. The tiles are encoded into a bitstream based on the tile group. The bitstream is stored for communication toward a decoder.