A method performed by a decoder for decoding a bitstream comprising a picture parameter set, PPS, and a first set of slices. The method includes obtaining the picture parameter set. The method also includes decoding a syntax element included in the picture parameter set to obtain an indicator value. The decoder is configured such that if the indicator value is set to a first value then the decoder determines that a picture header included in the bitstream comprises a parameter value corresponding to a particular parameter, otherwise the decoder determines that each slice included in the first set of slices comprises a parameter value corresponding to the particular parameter. If the picture header comprises the parameter value corresponding to the particular parameter, then this parameter value is used to decode slice data of each slice included in the first set of slices.

A video coding method using inter-layer prediction or referencing is provided. A video decoder receives data from a bitstream carrying data for video pictures in a plurality of different layers. At least one of the plurality of layers comprises temporal sublayers that correspond to levels in a hierarchical temporal prediction structure. Each temporal sublayer is associated with a temporal identifier. The video decoder receives an inter-layer prediction constraint parameter constraining a maximum temporal sublayer used in inter-layer prediction. The video decoder reconstructs a first picture in a first layer by referencing data of a second picture in a second layer. A temporal identifier of the referenced data satisfies the received inter-layer prediction constraint parameter.

A video data stream having a video encoded thereinto is provided. The video data stream comprises an indication that indicates whether or not one or more scalable nesting supplemental enhancement information messages comprising timing information for each of one or more output layer sets are present within the video data stream.

According to the disclosure of the present document, on the basis of NAL unit type-associated information on whether a picture has mixed NAL unit types, NAL unit types for slices within the picture can be determined, and for the picture having the mixed NAL unit types, not only IRAP but also a form mixed with NAL units of other types can be provided.

An apparatus (200) for receiving an input video data stream according to an embodiment is provided. The input video data stream has a video encoded thereinto. The apparatus (200) is configured to generate an output video data stream from the input video data stream.

A video processing method includes performing a conversion between a video comprising one or more pictures and a bitstream of the video according to a format rule. The format rule specifies that, in response to satisfying one or more conditions, a syntax element indicating whether a first syntax structure providing a profile, a tier and a level information and a second syntax structure providing decoded picture buffer information are present in a sequence parameter set is set to be equal to 1 to indicate that the first syntax structure and the second syntax structure are present in the sequence parameter set.

Methods and apparatus for video processing are disclosed. The processing may include video encoding, video decoding, or video transcoding. One example method includes performing a conversion between a current block of a video and a bitstream of the video. The bitstream conforms to a rule that specifies that a context index offset is used for including a first sign flag of a first coefficient in the bitstream. The rule specifies that a value of the context index offset is based on whether a first coding mode is applied on the current block in the bitstream.

Methods and apparatus for video processing are described. The processing may include video encoding, video decoding, or video transcoding. An example video processing method includes performing a conversion between a video and a bitstream of the video including one or more output layer sets according to a format rule. At least one of the one or more output layer sets consists of a trick mode access representation including only intra random access points pictures or only intra-coded pictures. The format rule specifies whether or how level information for the trick mode representation is indicated in the bitstream.

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).

Systems and methods for decoding a coded video stream are provided. A method includes receiving a coded video stream that includes an access unit, including a picture; signaling a first flag, in an access unit delimiter of the coded video stream, that indicates whether the access unit includes either or neither one from among an intra random access point (IRAP) picture and a gradual decoding refresh (GDR) picture; signaling a second flag, in a picture header of the coded video stream, that indicates whether the picture is the IRAP picture; and decoding the picture, as a current picture, based on the signaling of the first flag and the second flag, wherein a value of the first flag and a value of the second flag are aligned.