An identifying information generating unit that generates shared-process identifying information that identifies by which encoding processing and decoding processing a process shared between the encoding processing of image data and the decoding processing of an encoded stream is to be performed, or generates program identifying information that identifies which decoding program is to be selected from among a plurality of decoding programs that differ from each other in an assignment pattern in which a plurality of processes that constitute the decoding processing are assigned to a plurality of processing units or in an arrangement pattern of memories used by the plurality of processes. A transmitting unit that transmits the shared-process identifying information or the program selection information generated by the identifying information generating unit.