first access unit of the bitstream shall only contain coded slice NAL units with nal_unit_type equal to 5 or idr_flag equal to 1. The order of NAL units and coded pictures and their association to access units is described in clause G.7.4.1.2.3. G.7.4.1.2.3 Order of NAL units and coded pictures and association to access units The specification of clause 7.4.1.2.3 applies with the following modifications. NOTE - Some bitstreams that conform to one or more profiles specified in this annex do not conform to any profile specified in Annex A (prior to operation of the base layer extraction process specified in clause G.8.8.2). As specified in clauses 7.4.1 and 7.4.1.2.3, for the profiles specified in Annex A, NAL units with equal to 20 are classified as non-VCL NAL units that must be preceded within each access unit by at least one NAL unit with in the range of 1 to 5, inclusive. For this reason, any bitstream that conforms to one or more profiles specified in this annex does not conform to any profile specified in Annex A when it contains any of the following: - any access unit that does not contain any NAL units with nal_unit_type equal to 1 or 5, but contains one or more NAL units with nal_unit_type equal to 6, 7, 8, 9, or 15; any access unit in which one or more NAL units with nal_unit_type equal to 7, 8, or 15 is present after the last NAL unit in the access unit with nal_unit_type equal to 1 or 5. The association of VCL NAL units to primary or redundant coded pictures is specified in clause G.7.4.1.2.5. When the primary coded picture does not contain a layer representation with a particular value of DQId, all redundant coded pictures (when present) in the same access unit shall not contain a layer representation with the particular value of DQId. The constraints for the detection of the first VCL NAL unit of a primary coded picture are specified in clause G.7.4.1.2.4. The constraint expressed in clause 7.4.1.2.3 on the order of a buffering period SEI message is replaced by the following constraints. When an SEI 