Patent ID: 8050328

Claim:
An image decoding method for decoding each of a plurality of coded pictures in a stream with reference to a previously decoded picture that is stored in a memory, said image decoding method comprising: a first storage step of: sequentially decoding at least a portion of the plurality of coded pictures in the stream, so as to obtain a plurality of decoded pictures; storing, into the memory, a reference picture to be used as a reference for decoding from among the plurality of decoded pictures; and managing the reference picture stored in the memory; a determination step of determining whether or not random access reproduction has been designated; a state change step of, when said determination step determines that the random access reproduction has been designated, changing a management state for managing the reference picture stored in the memory; and a second storage step of, when said determination step determines that the random access reproduction has been designated: sequentially decoding at least a portion of the plurality of coded pictures from a random access reproduction destination with the changed management state for managing the reference picture stored in the memory as an initial management state, so as to obtain a plurality of decoded pictures; storing, into the memory, the reference picture to be used as the reference from among the plurality of decoded pictures decoded by said second storage step; and managing the reference picture stored in the memory by said second storage step based on the changed management state for managing the reference picture stored in the memory.