which it is contained. A decoder conforming to this Recommendation International Standard processes the syntax structures in decoding order and determines the semantics according to the position derived from that. G.7.4.1 NAL unit semantics The semantics for the syntax elements in clause G.7.3.1 are specified in clause 7.4.1. The following specifications additionally apply. For NAL units with nal_unit_type equal to 14, nal_ref_idc shall be identical to nal ref idc of the associated NAL unit, which succeeds the NAL unit with nal_unit_type equal to 14 in decoding order. The value of nal_refide shall be the same for all VCL NAL units of a dependency representation. The variable refNalRefIdc is derived as follows: If nal_unit_type is not equal to 20 or dependency_id is equal to the minimum value of dependency_id for all VCL NAL units of the coded picture, refNalRefIdc is set equal to 0. Otherwise (nal_unit_type is equal to 20 and dependency_io is not equal to the minimum value of dependency id for all VCL NAL units of the coded picture), refNalRefIdc is set equal to the maximum value of nal ref idc for all VCL NAL units of the coded picture with a value of dependency_id less than the current value of dependency_id. When refNalRefIdc is greater than 0, the value of shall not be equal to 0. nal_ref_idc equal to 0 for a NAL unit containing a slice and having a value of dependency id that is equal to the maximum value of dependency_id in the coded picture indicates that all coded slice NAL units of the coded picture are coded slice NAL units of a non-reference picture. nal_ref_idc greater than 0 for a NAL unit containing a slice and having a value of dependency_id that is equal to the maximum value of dependency_id in the coded picture indicates that all coded slice NAL units of the coded picture are coded slice NAL units of a reference picture. G.7.4.1.1 NAL unit header SVC extension semantics The syntax elements idr_flag, priority_id, no_inter_layer_pred_flag, dependency_id quality_id, temporal_id use_ref_base_pic_flag