A method of video processing includes performing a conversion between a video including a plurality of video layers and a bitstream of the video, wherein the bitstream includes a plurality of output layer sets (OLSs), each including one or more of the plurality of video layers, and the bitstream conforms to a format rule, wherein the format rule specifies that, for an OLS having a single layer, a profile-tier-level (PTL) syntax structure that indicates a profile, a tier and a level for the OLS is included in a video parameter set for the bitstream, and the PTL syntax structure for the OLS is also included in a sequence parameter set coded in the bitstream.