A method of decoding is provided. The method includes receiving a video bitstream including a picture unit (PU), where any decoding capability information (DCI) network abstraction layer (NAL) unit, video parameter set (VPS) NAL unit, sequence parameter set (SPS) NAL unit, or picture parameter set (PPS) NAL unit referred to by the PU precedes a picture header (PH) NAL unit of the PU and a first video coding layer (VCL) NAL unit of the PU; and decoding a coded picture from the PU to obtain a decoded picture.