Methods, systems, and 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, wherein the format rule specifies that values of one or more general constraint flags at a first level in the bitstream control occurrence of one or more syntax elements at a sequence parameter set (SPS) level or a picture header (PH) level or a slice header (SH) level.