-picture area in the decoded pictures for picture set picSubset corresponds to the luma frame sample at the luma frame sample location horizontal offset[i] vertical_offset[i]) in the decoded pictures for the picture set basePicSubset. The region represented by the sub-picture area in the decoded pictures for picture set picSubset represents an area of (region_width[ ])x(region_height[ luma frame samples in the decoded pictures for the picture set basePicSubset. (horizontal_offset[i 16) and (region_width[ % 16) shall both be equal to 0, and depending on the values of frame_mbs_only_flag for the primary coded VCL NAL units of the current scalable layer, the following applies: If frame_mbs_only_flag is equal to 1 for all primary coded VCL NAL units of the current scalable layer, (vertical_offset| i and (region_height[ % 16) shall both be equal to 0. Otherwise (frame_mbs_only_flag is equal to 0 for any primary coded VCL NAL units of the current scalable layer), (vertical_offset[i]%32) and (region_height[i]% shall both be equal to 0. When sub_pic_layer_flag[ i ] is equal to 1 and frm_size_info_present_flag[i] is equal to 1, the values of region_width[i and region_height[ shall be equal to (FrmWidthInMbs[i]<<4) and (FrmHeightInMbs[i] respectively. Rec. ITU-T H.264 (01/2012) roi_id[ specifies a region-of-interest identifier for the region represented by the current sub-picture scalable layer, which may be used for identifying the purpose of the current sub-picture scalable layer by an application. The value of roi_id[i shall be in the range of 0 to 63, inclusive. Let layerIdA and layerIdB be the layer identifiers of two scalable layers A and B, respectively, both of which having sub_pic_layer_flag[ ] equal to 1, and roildA and roidIdB be the region-of-interest identifiers of the scalable layers A and B, respectively. When layerIdA is less than layerIdB, roildA shall not be greater than roidIdB. iroi_grid_flag[ specifies how the IROI division information is indicated for the current scalable layer. iroi_grid_flag[ equal 