Abstract: A method of decoding is provided. The method includes receiving a picture unit (PU) including zero or one picture header (PH) network abstraction layer (NAL) unit and only one coded picture; and decoding the only one coded picture from the PU to obtain a decoded picture. A corresponding method of encoding is also provided. The method includes generating a PU including zero or one PH NAL units and only one coded picture; encoding the PU into a video bitstream; and storing the video bitstream for communication toward a video decoder.

Abstract: Methods, devices and systems for signalling the use of subpictures in coded video pictures are described. One example method of video processing includes performing a conversion between a video and a bitstream of a video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that a first syntax element, which indicates whether a picture of the video can be partitioned, is conditionally included in a picture parameter set (PPS) of the bitstream based on values of a second syntax element, which indicates whether identifiers of subpictures are signalled in the PPS, and a third syntax element, which indicates, in the PPS, a number of the subpictures.

Abstract: A video coding mechanism includes receiving a bitstream comprising a current picture including a sub-picture coded according to inter-prediction. Coded blocks contain candidate motion vectors for a current block of the sub-picture. The coded blocks include a collocated block from a different picture. A candidate list of candidate motion vectors for the current block are derived by excluding collocated motion vectors from the candidate list when the collocated motion vectors are included in the collocated block, when the collocated motion vectors point outside of the sub-picture, and when a flag is set to indicate the sub-picture is treated as a picture. A current motion vector for the current block is determined from the candidate list of candidate motion vectors. The current block is decoded based on the current motion vector. The current block is forwarded for display as part of a decoded video sequence.

Abstract: A method of decoding a coded video bitstream implemented by a video decoder. The coded video bitstream includes a plurality of reference picture list structures each containing a plurality of reference picture entries. The method includes parsing a flag that specifies a sign value of an absolute value of a delta picture order count (POC) associated with a short-term reference picture entry from the plurality of reference picture entries; parsing the absolute value of the delta POC associated with the short-term reference picture entry; generating a reference picture list based on the sign value of the absolute value of the delta POC and the absolute value of the delta POC; and performing inter-prediction based on the reference picture list to generate a reconstructed block.

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 comprising one or more output layer sets according to a rule, wherein the rule specifies that a supplemental enhancement information (SEI) network abstraction layer (NAL) unit that includes a scalable-nested SEI message carrying picture timing information is not included due to use of a same picture timing in all output layer sets in the bitstream.

Abstract: A method of decoding is provided. The method includes receiving a video bitstream including a picture unit (PU) having a picture header (PH) with a PH syntax structure, where the PH syntax structure includes the following syntax elements common for all slices of a coded picture associated with the PH syntax structure: a non-reference picture flag, a picture parameter set (PPS) identifier (ID), a picture order count (POC) least significant bit (LSB), a no output of prior pictures flag, a recovery point POC, and a picture output flag; and decoding the coded picture from the PU to obtain a decoded picture.

Abstract: A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a picture parameter set (PPS) in a PPS network abstraction layer (NAL) unit and a coded picture comprising a set of video coding layer (VCL) NAL units. A particular VCL NAL unit does not refer to the PPS NAL unit unless a value of a NAL unit header layer identifier (nuh_layer_id) of the PPS NAL unit is less than or equal to a value of a nuh_layer_id of the particular VCL NAL unit. The coded picture is decoded from the set of VCL NAL units based on the PPS in the PPS NAL unit to produce a decoded picture. The decoded picture is forwarded for display as part of a decoded video sequence.

Abstract: A method for implementing an adaptive colour transform (ACT) mode during image/video encoding and decoding includes performing a conversion between a current video block of a video and a bitstream of the video, wherein the current video block is coded using the ACT mode, wherein the conversion includes applying an inverse ACT transform on the current video block according to a rule, and wherein the rule specifies that a clipping operation, based on a bit depth of the current video block, is applied to an input of the inverse ACT transform.

Abstract: A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a picture parameter set (PPS) in a PPS network abstraction layer (NAL) unit and a coded picture comprising a set of video coding layer (VCL) NAL units. A particular VCL NAL unit does not refer to the PPS NAL unit unless a value of a NAL unit header layer identifier (nuh_layer_id) of the PPS NAL unit is less than or equal to a value of a nuh_layer_id of the particular VCL NAL unit. The coded picture is decoded from the set of VCL NAL units based on the PPS in the PPS NAL unit to produce a decoded picture. The decoded picture is forwarded for display as part of a decoded video sequence.

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.

Abstract: A method of decoding is provided. The method includes receiving a video bitstream including a plurality of layers having sublayers and a video parameter set (VPS) including a first flag having a first value, wherein the first flag having the first value specifies that temporal identifiers (IDs) of a highest sublayer representation for level information, decoded picture buffer (DPB) parameters, and hypothetical decoder refresh (HRD) parameters are not present in the VPS and are inferred to be equal to a maximum number of the sublayers that may be present in a layer of the plurality of layers specified by the VPS; obtaining the level information, the HRD parameters, and the DPB parameters corresponding to the temporal ID of the highest sublayer representation from the VPS; and decoding a picture from one of the plurality of layers to obtain a decoded picture. A corresponding method of encoding is also provided.

Abstract: A method implemented in an encoder for encoding a video bitstream that includes coded data for a plurality of pictures, each of the plurality of pictures comprises at least one slice. The method includes encoding a flag that indicates whether tile information for a picture is present in a picture parameter set or present in a slice header, where the tile information indicates a location of a slice within the picture; encoding the tile information in only the picture parameter set when the flag indicates that the tile information for the picture is encoded in the picture parameter set; encoding the tile information in only the slice header when the flag indicates that the tile information for the picture is encoded in the slice header; and encoding data of the picture in the video bitstream based on the tile information.

Abstract: A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a plurality of pictures. A no output of prior pictures flag (NoOutputOfPriorPicsFlag) is set when a value of maximum picture width in luma samples (PicWidthMaxInSamplesY) for a current access unit (AU) is different from a value of PicWidthMaxInSamplesY for a preceding AU in decoding order. A decoded picture buffer (DPB) is emptied without output of contained pictures based on a value of the NoOutputOfPriorPicsFlag. A current picture is decoded and stored in the DPB. The current picture is output from the DPB for display as part of a decoded video sequence.

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: A method of decoding a coded video bitstream includes obtaining a reference picture list structure for a current slice represented in the coded video bitstream, wherein the reference picture list structure contains a number of entries; obtaining a default number of active entries in a reference picture list for the current slice; constructing a reference picture list for the current slice, the reference picture list containing a number of active and inactive entries; setting the number of active entries in the reference picture list equal to the number of entries in the reference picture list structure when the default number of active entries in the reference picture list is greater than the number of entries in the reference picture list structure; and obtaining, based on at least one active entry of the reference picture list, at least one reconstructed block of the current slice.

Abstract: A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a flag and a picture including a tile with a tile boundary. The tile is decoded. Filtering operations are performed across the tile boundary when the flag is set to a first value. The filtering operations across the tile boundary are omitted when the flag is set to a second value. The tile is forwarded for display as part of a decoded video sequence.

Abstract: A video coding mechanism is disclosed. The mechanism includes receiving at a decoder, a bitstream including a video coding layer (VCL) network abstraction layer (NAL) unit containing a slice of image data divided into a plurality of tiles. A number of the tiles in the VCL NAL unit are determined. A number of entry point offsets for the tiles is also determined as one less than the number of the tiles in the VCL NAL unit. Each entry point offset indicates a starting location of a corresponding tile in the VCL NAL unit. The number of entry point offsets is not explicitly signaled in the bitstream. The entry point offsets for the tiles are obtained based on the number of entry point offsets. The tiles are decoded at the entry point offsets to generate a reconstructed image.

Abstract: A mechanism for processing visual media data is disclosed. An extended dependent random access point (EDRAP) sample is determined. The EDRAP sample is a sample for which all subsequent samples in both decoding and output order can be correctly decoded provided that required preceding streaming access point (SAP) or EDRAP samples are available for referencing when decoding the EDRAP sample and the subsequent samples. A conversion is performed between a visual media data and a media data file based on the EDRAP sample.

Abstract: A video coding mechanism is disclosed. The mechanism includes encoding a bitstream comprising one or more output layer sets (OLSs). A video parameter set (VPS) specifying the OLS is also encoded into the bitstream. A set of bitstream conformance tests are performed at each operation point (OP) of each OLS, as specified by the VPS, to test each OP for conformance. The bitstream is stored for communication toward a decoder.

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 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.