US Patent 11909966 Syntax constraints in parameter set signaling of subpictures

An example method of video processing includes performing a conversion between a picture of a video and a bitstream representation of the video. The picture includes one or more sub-pictures, and the bitstream representation conforms to a format rule that specifies that a length of a syntax element is equal to Ceil(Log 2(SS)) bits. SS is greater than 0, and the syntax element indicating a horizontal or a vertical position of a top-left corner of a coding tree unit of a sub-picture of the picture.