Decoders shall ignore (remove from the bitstream and discard) the contents of all NAL units that use reserved values of nal_unit_type. NOTE 3 - This requirement allows future definition of compatible extensions to this Recommendation | International Standard. NOTE 4 - In previous editions of this Recommendation | International Standard, the NAL unit types 13..15 and 19..20 (or a subset of these NAL unit types) were reserved and no decoding process for NAL units having these values of nal unit type was specified. In later editions of this Recommendation | International Standard, currently reserved values of nal unit type might become non-reserved and a decoding process for these values of nal_unit_type might be specified. Encoders should take into consideration that the values of nal_unit_type that were reserved in previous editions of this Recommendation International Standard might be ignored by decoders. In the text, coded slice NAL unit collectively refers to a coded slice of a non-IDR picture NAL unit or to a coded slice of an IDR picture NAL unit. The variable IdrPicFlag is specified as IdrPicFlag = ( (nal_unit_type (7-1) When the value of nal_unit_type is equal to 5 for a NAL unit containing a slice of a particular picture, the picture shall not contain NAL units with nal unit type in the range of 1 to 4, inclusive. For coded video sequences conforming to one or more of the profiles specified in Annex A that are decoded using the decoding process specified in clauses 2-9, such a picture is referred to as an IDR picture. NOTE 5 - Slice data partitioning cannot be used for IDR pictures. svc_extension_flag indicates whether a al_unit_header_svc_extension() or mnal_unit_header_mvc_extension() will follow next in the syntax structure. The value of svc_extension_flag shall be equal to 1 for coded video sequences conforming to one or more profiles specified in Annex G. Decoders conforming to one or more profiles specified in Annex G shall ignore (remove from the bitstream and discard) NAL units for which nal_unit_