unit has a coded video sequence as its scope), it shall be contained in the first access unit to which it applies. It is a requirement of bitstream conformance that, when an end of stream NAL unit is present in an access unit, this access unit shall be the last access unit in the bitstream and the end of stream NAL unit shall be the last NAL unit in that access unit. Rec. ITU-T H.264 (01/2012) 7.4.1.2.3 Order of NAL units and coded pictures and association to access units This clause specifies the order of NAL units and coded pictures and association to access unit for coded video sequences that conform to one or more of the profiles specified in Annex A and are decoded using the decoding process specified in clauses 2-9. NOTE 1 - Some bitstreams that conform to profiles specified in Annexes G or H may violate the NAL unit order specified in this subclause. Conditions under which such a violation of the NAL unit order occurs are specified in clauses G.7.4.1.2.3 and H.7.4.1.2.3. An access unit consists of one primary coded picture, zero or more corresponding redundant coded pictures, and zero or more non-VCL NAL units. The association of VCL NAL units to primary or redundant coded pictures is described in clause 7.4.1.2.5. The first access unit in the bitstream starts with the first NAL unit of the bitstream. The first of any of the following NAL units after the last VCL NAL unit of a primary coded picture specifies the start of a new access unit: access unit delimiter NAL unit (when present), sequence parameter set NAL unit (when present), picture parameter set NAL unit (when present), SEI NAL unit (when present), NAL units with nal_unit_type in the range of 14 to 18, inclusive (when present), first VCL NAL unit of a primary coded picture (always present). The constraints for the detection of the first VCL NAL unit of a primary coded picture are specified in clause 7.4.1.2.4. The following constraints shall be obeyed by the order of the coded pictures and non-VCL NAL units within an access unit: When an access un