An example device for processing video data includes memory configured to store the video data and one or more processors implemented in circuitry and coupled to the memory. The one or more processors are configured to parse a first parameter set, the first parameter set being signaled in a bitstream data once per sequence of a group of encoded pictures. The one or more processors are configured to parse one or more dynamic range adjustment (DRA) syntax elements in a second parameter set, the second parameter set being signaled in the bitstream and being related to at least one picture in the group of encoded pictures, wherein the parsing of the one or more DRA syntax elements is not dependent on any syntax element of the first parameter set, and process the at least one picture based on the first parameter set and the second parameter set.

A method, computer program, and computer system is provided for coding video data. Video data including one or more subpictures is received. A network abstraction layer (NAL) unit type associated with each of the one or more subpictures is identified based on checking a flag corresponding to mixed NAL units in the one or more subpictures. The video data is decoded based on the identified NAL unit types.

A method includes performing a conversion, according to a rule, between a current slice of a current picture of a video and a bitstream of the video, wherein the rule specifies that a first syntax element of a picture parameter set (PPS) and a second syntax element of the PPS control whether a third syntax element is included in the bitstream, and wherein the first syntax element indicates whether a weighted prediction is enabled for bi-directional slices of coded pictures referring to the PPS, the second syntax element indicates whether information related to the weighted prediction is present in picture headers or slice headers of coded pictures referring to the PPS, and the third syntax element indicates a number of weights associated with a reference picture list 1 of the current slice.

Disclosed herein are an image encoding and decoding method and apparatus for signaling information on a subpicture and picture header, and a method of transmitting a bitstream. The image decoding method according to the present disclosure may include acquiring a first flag specifying whether information on a subpicture is present in a bitstream, acquiring a second flag specifying whether picture header information is present in a slice header, and decoding the bitstream based on the first flag and the second flag. When the first flag specifies that the information on the subpicture is present in the bitstream, the second flag may have a value specifying that the picture header information is not present in the slice header.

An encoder includes: circuitry; and memory coupled to the circuitry. In the encoder, in operation, the circuitry: performs calculation that involves multiplication and from which a plurality of discrete integers are yieldable as a calculation result, to derive one of the plurality of discrete integers as a quantization parameter threshold; and when orthogonal transform is skipped for a current block of an image, determines a quantization parameter value for the current block, using the quantization parameter threshold. The calculation involves multiplying a first value by a first fixed value, the first value and the first fixed value being each an integer. The first value is a limit value to be included in a header of a bitstream.

Methods and devices for decoding a video stream are provided, a method includes storing previously decoded pictures of the video stream in a decoded picture buffer, including a plurality of first pictures of a same temporal sub-layer, the plurality of first pictures including at least one sub-layer reference picture for predicting a current picture of the video stream; identifying a network abstract layer (NAL) unit type of a picture of the plurality of first pictures; removing, based on the NAL unit type of the picture identified, the picture from the decoded picture buffer; and decoding the current picture using the decoded picture buffer. The decoding includes predicting the current picture using one or more of the at least one sub-layer reference picture that is stored within the decoded picture buffer, after removing the picture from the decoded picture buffer.

A method of video processing includes performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies that a sub-bitstream extraction process is implemented to generate a sub-bitstream for decoding, wherein the sub-bitstream extraction process is configured to extract, from the bitstream, a sub-bitstream with a target highest temporal identifier, and wherein, the rule specifies that, during the extracting, upon removing a video coding layer (VCL) network abstraction layer (NAL) unit, filler data units and filler supplemental enhancement information (SEI) messages in SEI NAL units that are associated with the VCL NAL unit are also removed.

Systems, methods and apparatus for processing image data are described. One example method includes performing a conversion between a visual media file and a bitstream. The visual media file comprises image items each comprising a sequence of one or more pictures according to a media file format, and the bitstream comprises access units each comprising one or more pictures each belonging to a layer according to a video coding format. The video coding format defines multiple profiles. The media file format specifies that the bitstream is represented in a file having a specific brand, and that one or more profiles used for representing the video in the bitstream are agnostic of the specific brand.

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 one or more pictures including one or more subpictures and a bitstream of the video. The bitstream conforms to a format rule that specifies that a subpicture cannot be a random access type of subpicture in response to the subpicture not being a leading subpicture of an intra random access point subpicture. The leading subpicture precedes the intra random access point subpicture in output order.

Methods and apparatus for processing of video are described. A video processing method includes performing a conversion between a video including multiple layers of one or more pictures and a bitstream of the video according to a format rule. The format rule specifies that a reference picture referred to by each inter-layer reference picture entry in a reference picture list of a slice of a current picture of a current layer satisfies a constraint. The constraint is at least one of: (a) the reference picture is an intra random access (IRAP) picture or (b) the reference picture has a temporal identifier that is less than or equal to a certain value that is a function of a maximum allowed value of a video layer to which slices from the current layer can reference. The maximum allowed value is indicated in a syntax element.