Decoder, decoding method, re-encoder, re-encoding method, decoding program and re-encoding program embodied on computer-readable meduim

摘要

When decoding encoded information encoded according to an MPEG method to generate decoded information, a superimposition unit generates the decoded information by embedding identification information in a still image reproduced from an I picture contained in a GOP constituting the encoded information, the identification information indicating that the still image is obtained by decoding the I picture. In re-encoding, the identification information is detected from the generated decoded information, and the decoded information is encoded again with reference to the still image having contained the identification information.