, discardable_flag, and output_flag, when present in a prefix NAL unit, are considered as if they were present in the associated NAL unit. idr flag equal to 1 specifies that the current coded picture is an IDR picture when the value of dependency_id for the NAL unit is equal to the maximum value of dependency in the coded picture. flag equal to 0 specifies that the current coded picture is not an IDR picture when the value of dependency_i for the NAL unit is equal to the maximum value of dependency_id in the coded picture. The value of dr_flag shall be the same for all NAL units of a dependency representation. NOTE 1 - The classification of a coded picture as IDR picture and the partitioning of a sequence of access units in coded video sequences depends on the maximum value of dependency_id that is present in the associated NAL units. When NAL units are removed from a bitstream, e.g. in order to adjust the bitstream to the capabilities of a receiving device, the maximum value of dependency id in the coded pictures may change and hence the classification of coded pictures as IDR pictures may change and with that the partitioning of the sequence of access units into coded video sequences may change. When idr_flag is equal to 1 for a prefix NAL unit, the associated NAL unit shall have nal_unit_type equal to 5. When dr_flag is equal to 0 for a prefix NAL unit, the associated NAL unit shall have nal_unit_type equa to 1. When nal ref idc is equal to 0, the value of idr_flag shall be equal to 0. For NAL units, in which dr_flag is present, the variable IdrPicFlag derived in clause 7.4.1 is modified by setting it equal to flag. priority_id specifies a priority identifier for the NAL unit. The assignment of values to priority_id is constrained by the sub-bitstream extraction process as specified in clause G.8.8.1. Rec. ITU-T H.264 (01/2012) NOTE 2 - The syntax element priority_io is not required by the decoding process specified in this Recommendation | International Standard. The syntax element priority_id may be used as 