 Detection of the first VCL NAL unit of a primary coded picture This clause specifies constraints on VCL NAL unit syntax that are sufficient to enable the detection of the first VCL NAL unit of each primary coded picture. The first VCL NAL unit of the primary coded picture of the current access unit, in decoding order, shall be different from the last VCL NAL unit of the primary coded picture of the previous access unit, in decoding order, in one or more of the following ways: view of the first VCL NAL unit of the primary coded picture of the current access unit is different from view id of the last VCL NAL unit of the primary coded picture of the previous access unit, and VOIdx of the first VCL NAL unit of the primary coded picture of the current access unit is less than VOIdx of the last VCL NAL unit of the primary coded picture of the previous access unit. view id of the first VCL NAL unit of the primary coded picture of the current access unit is equal to view id of the last VCL NAL unit of the primary coded picture of the previous access unit, and any of the conditions specified in clause 7.4.1.2.4 is fulfilled. Rec. ITU-T H.264 (01/2012) H.7.4.1.2.5 Order of VCL NAL units and association to coded pictures Each VCL NAL unit is part of a coded picture. Let voldx be the value of VOIdx of any particular VCL NAL unit. The order of the VCL NAL units within a coded picture is constrained as follows: For all VCL NAL units following this particular VCL NAL unit, the value of VOIdx shall be greater than or equal to voldx. For each set of VCL NAL units within a view component, the following applies: If arbitrary slice order, as specified in Annex A or clause H.10, is allowed, coded slice NAL units of a view component may have any order relative to each other. Otherwise (arbitrary slice order is not allowed), coded slice NAL units of a slice group shall not be interleaved with coded slice NAL units of another slice group and the order of coded slice NAL units within a slice group shall be in the order of increasing mac