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 a number of entries in a reference picture list of the current picture is greater than 0 in response to (1) one or more slices in the current picture being allowed to have a slice type other than an Intra (I) slice type, and (2) reference picture list (RPL) information being present in a picture header.

Abstract: A method includes determining, for a conversion between a video block of a video and a bitstream of the video, a size of prediction block corresponding to the video block according to a rule. The method also includes performing the conversion based on the determining. The rule specifies that a first size of the prediction block is determined responsive to whether a prediction refinement using optical flow technique is used for coding the video block. The video block has a second size and is coded using an affine merge mode or an affine advanced motion vector prediction mode.

Abstract: A video processing method is provided to include performing a conversion between a video and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies a condition that controls whether or how one or more syntax elements related to picture order counts for a long term reference picture are included in a reference picture list syntax structure in the bitstream.

Abstract: A method of video processing is provided that includes performing a conversion between a block of a video and a bitstream of the video. The bitstream conforms to a formatting rule specifying that a size of a merge estimation region (MER) is indicated in the bitstream and the size of the MER is based on a dimension of a video unit. The MER comprises a region used for deriving a motion candidate for the conversion.

Abstract: Methods, apparatus, systems for performing video processing such as video encoding, video decoding or video transcoding are described. One example method of video processing includes performing a conversion between a video comprising one or more video layers and a bitstream of the video according to a rule. The rule specifies that responsive to a value of a first field in a sequence parameter set (SPS) that is referred to by a video layer, a second field in a video parameter set referred to by the SPS that is indicative of a maximum number of sublayers allowed in the bitstream is construed to be equal to a third field in the SPS. The third field is indicative of a maximum number of sublayers allowed in the video layer.

Abstract: Methods, apparatus, systems for video processing, including video encoding or video decoding are described. One example method includes performing a conversion between a video comprising a video picture that includes a video slice and a bitstream of the video. The bitstream conforms to a format rule specifying that, in case a slice type of the video slice is type P and temporal motion vector prediction is enabled, usage of reference picture resampling (RPR) for a reference picture in a collocated reference picture list is disabled. The reference picture is indicated by a reference index of a collocated picture of the video slice used for the temporal motion vector prediction.

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 constraints on values of one or more first syntax elements in an adaptation parameter set are defined based on semantics of second syntax elements in a picture header and/or a slice header when a picture or a slice referring to the adaptation parameter set.

Abstract: 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.

Abstract: Devices, systems and methods related to digital video coding, and specifically, to signaling of slice types in video picture headers are described. One example method of video processing includes performing a conversion between a video including one or more video pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that for a video picture of the one or more video pictures having all slices coded as I slices, P slice and B slice related syntax elements are omitted from a picture header for the video picture.

Abstract: Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a block of a video and a bitstream of the video according to a rule. The rule specifies that whether a syntax flag indicating whether transform skip residual coding is enabled at a video unit level is present in the bitstream is based on values of a first syntax element indicating usage of sign data hiding in the video unit and a second syntax element indicating usage of dependent quantization in the video unit.

Abstract: Video processing, including video coding, video decoding and video transcoding, is described. One example method includes performing a conversion between a video comprising a video picture and a bitstream of a video according to a rule, where the rule specifies that syntax elements indicate a first width and a first height of a scaling window for the video picture, and where the rule specifies that a range of permissible values for the syntax elements include values greater than or equal to two times a second width of the video picture and two times a second height of the video picture.

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: 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: 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: 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: 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: 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: 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: Techniques for video processing, including video coding, video decoding and video transcoding are described. One example method includes performing a conversion between a video including a video picture including a video tile including one or more slices and a bitstream of the video according to a rule. The rule specifies that a second slice in a tile that includes a first slice in a picture has a height that is represented in a unit of coding tree units. The first slice has a first slice index, and the second slice has a second slice index that is determined based on the first slice index and a number of explicitly provided slice heights in the video tile. The height of the second slice is determined based on the first slice index and the second slice index.