SUB-BITSTREAM EXTRACTION

Systems, methods and apparatus for encoding, decoding or transcoding digital video are described. One example method of video processing includes performing a conversion between a video and a bitstream of the video, wherein the bitstream conforms to an order of a sub-bitstream extraction process that is defined by a rule that specifies (a) the sub-bitstream extraction process excludes an operation that removes all supplemental enhancement information (SEI) network abstraction layer (NAL) units, which satisfy a condition, from an output bitstream or (b) the order of the sub-bitstream extraction process includes replacing parameter sets with replacement parameter sets prior to removing, from an output bitstream, the SEI NAL units.