Abstract: A video coding mechanism for viewpoint dependent video coding is disclosed. The mechanism includes mapping a spherical video sequence into a plurality of sub-picture video sequences. The mechanism further includes encoding the plurality of sub-picture video sequences as sub-picture bitstreams to support merging of the plurality of sub-picture bitstreams, the encoding ensuring that each sub-picture bitstream is self-referenced and two or more of the sub-picture bitstreams can be merged to generate a single video bitstream using a lightweight bitstream rewriting process that does not involve changing of any block-level coding results. A mergeable indication is encoded to indicate that the sub-picture bitstream containing the indication is compatible with a multi-bitstream merge function for reconstruction of the spherical video sequence. A set of the sub-picture bitstreams and the mergeable indication are transmitted toward the decoder to support decoding and displaying a virtual reality video viewport.

Abstract: A video coding mechanism for viewpoint dependent video coding is disclosed. The mechanism includes mapping a spherical video sequence into a plurality of sub-picture video sequences. The mechanism further includes encoding the plurality of sub-picture video sequences as sub-picture bitstreams to support merging of the plurality of sub-picture bitstreams, the encoding ensuring that each sub-picture bitstream is self-referenced and two or more of the sub-picture bitstreams can be merged to generate a single video bitstream using a lightweight bitstream rewriting process that does not involve changing of any block-level coding results. A mergable indication is encoded to indicate that the sub-picture bitstream containing the indication is compatible with a multi-bitstream merge function for reconstruction of the spherical video sequence. A set of the sub-picture bitstreams and the mergable indication are transmitted toward the decoder to support decoding and displaying a virtual reality video viewport.

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 multiple syntax elements are used to specify usage of a reference picture resampling tool.

Abstract: Methods and apparatus for processing of video are described. The processing includes video encoding, decoding, or transcoding. A 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 trailing subpicture that is associated with an intra random access point subpicture or a gradual decoding refresh subpicture follows the intra random access point subpicture or the gradual decoding refresh subpicture in an order.

Abstract: Methods and apparatus for video processing are described. The video processing may include video encoding, video decoding or video transcoding. One example video processing method includes performing a conversion between a video comprising a picture in a video unit and a bitstream of the video according to a format rule. The format rule specifies that, responsive to a width of a picture being equal to a maximum allowed picture width in the video unit and a height of the picture being equal to a maximum allowed picture height in the video unit, a conformance window flag in a picture parameter set corresponding to the picture is set to a zero value.

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: Methods and apparatus for video processing, including coding and decoding, are described. One example video processing method includes performing a conversion between a video having one or more video layers and a bitstream of the video according to a format rule, and wherein the format rule specifies that a value of a variable indicating whether to output a picture in an access unit is determined based on a flag indicating whether to output another picture in the access unit.

Abstract: Methods and apparatus for video processing, including coding and decoding, are described. One example video processing method includes performing a conversion between a video having one or more video layers and a bitstream of the video according to a format rule, and wherein the format rule specifies that a value of a flag that indicates whether to remove pictures previously decoded and stored in a decoded picture buffer from the decoded picture buffer when decoding an access unit of a certain type is included in the bitstream.

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.

Abstract: Methods and apparatus for video processing, including coding and decoding, are described. One example video processing method includes performing a conversion between a video and a bitstream of the video according to a format rule, wherein the bitstream includes one or more output layer sets (OLSs), each OLS comprising one or more coded layer video sequences, and wherein the format rule specifies that a video parameter set indicates, for each of the one or more OLSs, a greatest allowed value of a chroma format indicator and/or a greatest allowed value of a bit depth used to represent pixels of the video.

Abstract: Methods, systems, apparatuses 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 to include, in a general constraint syntax structure associated with the video, one or more general constraint flags indicating whether corresponding syntax elements are included in a sequence parameter set (SPS) and/or a picture parameter set (PPS) and/or a picture header (PH) and/or a slice header (SH) or to constrain values of the syntax elements in the SPS and/or the PPS and/or the PH and/or the SH.

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: 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 a current picture including a current subpicture including a current slice and a bitstream of the video. The bitstream conforms to a format rule that disallows an active entry in a reference picture list of the current slice from including a first picture that precedes in a decoding order a second picture that includes a step-wise temporal sublayer access subpicture in response to conditions associated with at least the first picture and the current subpicture.

Abstract: A video processing method includes performing a conversion between a video having one or more video layers including one or more video pictures and a bitstream of the video according to a format rule. The format rule specifies that a first video picture is an associated intra random access point picture of a second picture and that the second picture are constrained to belong to a same video layer.

Abstract: A video processing method includes performing a conversion between a video having one or more video layers comprising a current picture comprising a current slice and a bitstream of the video according to a rule. The rule specifies a condition under which a reference picture list for the current slice is disallowed to have an active entry that refers to a picture that precedes, in a decoding order or an output order, an intra random access point picture associated with the current picture.

Abstract: A video processing method includes performing a conversion between a video that includes a picture with two neighboring subpictures and a bitstream of the video. The bitstream conforms to a format rule that specifies that the two neighboring subpictures with different types of network abstraction layer (NAL) units have syntax elements with a same first value that indicates whether each of the two neighboring subpictures in a coded layer video sequence is treated as a picture.

Abstract: 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 includes access units each consisting of one or more pictures each belonging to a layer according to a video coding format. The media file format specifies that image items comprising pictures originated from the bitstream are allowed to be associated with different instances of a property descriptor that indicates high-level characteristics of the bitstream.

Abstract: Provided are methods of controlling disassociation of cells from a carrier, compositions, and methods of collecting cells. The methods of controlling disassociation of cells from a carrier may include contacting a polymeric carrier with one or more digesting agents to disassociate at least a portion of a plurality of cells from the polymeric carrier. The polymeric carrier may be crosslinked with a crosslinker including at least one of a redox sensitive moiety, a UV light sensitive moiety, a pH sensitive moiety, and a temperature sensitive moiety.

Abstract: A method of encoding a video bitstream implemented by a video encoder is disclosed. The method includes storing, in a memory of the video encoder, a set of less than five network abstraction layer (NAL) unit types available for video data; selecting, by a processor of the video encoder, a NAL unit type from the set of less than five NAL unit types for a picture from the video data; generating, by the processor of the video encoder, a video bitstream containing a NAL unit corresponding to the NAL unit type selected and containing an identifier identifying the NAL unit type selected; and transmitting, by a transmitter of the video encoder, the video bitstream toward a video decoder. A corresponding method of decoding the video bitstream is also disclosed.

Abstract: A method of processing media data. The method includes determining, for a conversion between the media data and a media data file, whether a size and a position of a target picture-in-picture region in a main video are present in the media data file, wherein a supplementary video appears to be overlaid on the target picture-in-picture region when the main video is displayed; and performing the conversion between the media data and the media data file based on the size and the position determined. A corresponding video coding apparatus and non-transitory computer-readable recording medium are also disclosed.