CPC H04N 19/119 (2014.11) [H04N 19/172 (2014.11); H04N 19/174 (2014.11); H04N 19/176 (2014.11); H04N 19/184 (2014.11); H04N 19/96 (2014.11)] | 19 Claims |
1. A video processing method, comprising:
performing a conversion between a video comprising a video picture and a bitstream of the video,
wherein the video picture comprises one or more tiles that form one or more tile rows and one or more tile columns,
wherein the bitstream conforms to a format rule,
wherein the format rule specifies that a tile column index is derived for each coding tree block (CTB) column of a tile of the video picture,
wherein the video picture also comprises one or more subpictures,
wherein each subpicture comprises one or more slices that collectively form a rectangular subset of the video picture,
wherein the format rule further specifies that a width of a subpicture in units of tile columns is derived based on tile column indices of a left-most CTB and/or a right-most CTB included in the subpicture,
wherein a width of an i-th subpicture in units of tiles columns, denoted as SubpicWidthInTiles[i], is derived as follows:
a loop is performed with i as a loop variable, wherein an initialization of the loop variable i is equal to 0, and a value of the loop variable i is incremented by one after each execution in the loop,
when i is smaller than or equal to sps_num_subpics_minus1, for each i, an execution is performed to:
set leftX equal to sps_subpic_ctu_top_left_x[i],
set rightX equal to leftX+sps_subpic_width_minus1[i], and
set SubpicWidthInTiles[i] equal to
ctbToTileColIdx[rightX]+1−ctbToTileColIdx[leftX],
wherein sps_num_subpics_minus1 plus 1 represents a number of subpictures in the video picture,
wherein sps_subpic_ctu_top_left_x[i] represents a horizontal position of a top-left CTB of the i-th subpicture,
wherein sps_subpic_width_minus1[i] plus 1 specifies the width of the i-th subpicture, and
wherein ctbToTileColIdx[rightX] and ctbToTileColIdx[leftX] represent the tile column indices of the left-most CTB and the right-most CTB, respectively, included in the subpicture.
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