respectively, in tile raster scan order (of the identifier grid or the tile grid, whichever is applicable according to other embodiments). [00181] In an embodiment, a motion-constrained set of tiles and/or slices is indicated in or along the bitstream, e.g. in syntax structures of VPS, SPS, PPS, and/or an SEI message. The absence of the motion-constraint indication syntax in the containing structure may indicate the absence of motion-constrained tile and/or slice sets. For example, the following syntax may be used: identifier grid or the tile grid (whichever is applicable according to other embodiments) in the picture is included in an motion-constrained set of tiles or slices. each_grid_cell_one_mc_set_flag equal to 1 indicates that each and every grid cell in the identifier grid or the tile grid (whichever is applicable according to other embodiments) in the picture is included in an motion-constrained set of tiles or slices. each_grid_cell_one_mc_set_flag equal to 0 indicates that such constraint may not be applied. num sets minusl specifies the number of motion-constrained sets of tiles or slices identified in this syntax structure minus one. mc_set_id[ i ] specifies an identifier of the i-th motion- constrained set of tiles or slices. num_cell_rects_in_set_minusl[ i ] plus 1 specifies the number of rectangular regions of grid cells (of the identifier grid or the tile grid, whichever is applicable according to other embodiments) in the i-th motion-constrained set. top_left_cell_index[ i ][ j ] and bottom_right_cell_index[ i ][ j ] identify the grid cell position of the top-left cell and the grid cell position of the bottom-right cell in a rectangular region of the i-th identified motion-constrained set, respectively, in tile raster scan order (of the identifier grid or the tile grid, whichever is applicable according to other embodiments). [00183] In an embodiment, an encoder indicates in or along the bitstream, e.g. in a VPS or SPS, and/or a decoder decodes from or along the bitstream, e.g. from a VPS or SPS, if