Systems, methods and apparatus for storing or parsing a visual media file according a file format include performing a conversion between a visual media data and a visual media file that stores a bitstream of the visual media data according to a format rule. The visual media file stores one or more tracks comprising one or more video layers. The format rule specifies that whether a first set of syntax elements indicative of layer dependency information is stored in the visual media file is dependent on whether a second syntax element indicating that all layers in the visual media file are independent has a value 1.

Systems, methods and apparatus for visual media data processing are described. One method includes performing a conversion between a visual media data and a visual media file that stores a bitstream of the visual media data in multiple tracks according to a format rule that specifies that the file-level information includes a syntax element that identifies one or more tracks from the multiple tracks that contain a specific type of sample group that includes operation point information.

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 video pictures in a video layer and a bitstream of the video according to a rule, wherein the rule specifies that, in a process of sub-bitstream extraction, removal of (i) a video coding layer (VCL) network abstraction layer (NAL) unit, (ii) filler data NAL units associated with the VCL NAL unit, and (iii) filler payload supplemental enhancement information (SEI) messages associated with the VCL NAL unit is performed regardless of an availability of an external means used to replace a parameter set that is removed during the sub-bitstream extraction.

Systems, methods and apparatus for encoding, decoding or transcoding digital video are described. One example method of processing video data includes performing a conversion between a video and a bitstream of the video according to a format rule, wherein the format rule specifies that a supplemental enhancement information field or a video usability information syntax structure included in the bitstream indicates whether the bitstream comprises a multiview bitstream in which multiple views are coded in multiple video layers.

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 multiple layers and a bitstream of the video according to a rule, wherein the rule specifies that, in a first process of sub-bitstream extraction to output a first output sub-bitstream, the first output sub-bitstream is extracted without removing network abstraction layer (NAL) units of a particular type and having a particular NAL unit header identifier value, and wherein the particular type includes an access unit delimiter (AUD) NAL unit.

Techniques for selectively transforming one or more coding units when coding video content are described herein. The techniques may include determining whether or not to transform a particular coding unit. The determination may be based on a difference in pixel values of the particular coding unit and/or one or more predefined rate-distortion constraints. When it is determined to not perform a transform, the particular coding unit may be coded without transforming the particular coding unit.

A mechanism for processing video data is disclosed. Information in a Decoding Capability Information (DCI) network abstraction layer (NAL) unit is determined. A rule constrains usage of the DCI NAL unit in a Versatile Video Coding (VVC) Common Media Application Format (CMAF) track. A conversion is performed between a visual media data and a media data file based on the DCI NAL unit.

A mechanism for processing video data is disclosed. Information in a sequence parameter set (SPS) in a Versatile Video Coding (VVC) Common Media Application Format (CMAF) track is determined. A rule specifies a value of a video usability information progressive source flag (vui_progressive_source_flag) field in the SPS shall be equal to one. A conversion is performed between a visual media data and a media data file based on the SPS.

A mechanism for processing video data is disclosed. Information in a Decoding Capability Information (DCI) network abstraction layer (NAL) unit is determined. A rule specifies a value of a DCI number of profile, tier, and level (PTL) minus one (dci_num_ptls_minus1) in a Versatile Video Coding (VVC) Common Media Application Format (CMAF) track shall be zero.

Techniques for selectively transforming one or more coding units when coding video content are described herein. The techniques may include determining whether or not to transform a particular coding unit. The determination may be based on a difference in pixel values of the particular coding unit and/or one or more predefined rate-distortion constraints. When it is determined to not perform a transform, the particular coding unit may be coded without transforming the particular coding unit.