A method, apparatus, article of manufacture, and a memory structure for signaling extension functions used in decoding a sequence comprising a plurality of pictures, each picture processed at least in part according to a picture parameter set is disclosed. In one embodiment, the method comprises reading a first extension flag signaling a first extension function in the processing of the sequence and determining if the first extension flag has a first value. Further, the method reads a second extension flag signaling a second extension function in the processing of the sequence and performs the second extension function according to the read second extension flag only if the first extension flag has a first value.