A compressively-encoding-resultant video signal resulting from compressively encoding a video signal, a first compressively-encoding-resultant audio signal resulting from compressively encoding a first audio signal having a synchronized relation with the video signal, a reference clock information signal relating to synchronization between the compressively-encoding-resultant video signal and the first compressively-encoding-resultant audio signal, and an indication timing information signal designating an indication timing of the video signal are multiplexed to get an AV multiplexing-resultant signal. A second audio signal is compressively encoded to get a second compressively-encoding-resultant audio signal. A sound-production-timing information signal is added to the second compressively-encoding-resultant audio signal to get a substitution playback audio signal. During playback, the substitution playback audio signal can be reproduced instead of the first audio signal while being synchronous with the video signal. The sound-production-timing information signal responds to the reference clock information signal, and relates to synchronization with the video signal.