Patent ID: 7127736

Claim:
A communication apparatus comprising: receiving means for receiving operation data obtained by each user for dynamic data played back by a playback apparatus; storage means for storing the operation data received by said receiving means; digest-information generating means for generating digest information of the dynamic data according to the operation data stored in said storage means; and transmission means for transmitting the digest information generated by said digest-information generating means to at least one of the playback apparatuses, wherein said receiving means receives the operation data indicating at least one of instructions to fast forward, rewind and pause the dynamic data played back by the playback apparatus, wherein said receiving means receives playback-portion identification information indicating a playback portion of the dynamic data played back by the playback apparatus; and said digest-information generating means comprises statistical processing means for accumulating playback times of the playback portion based on the playback-portion identification information received by said receiving means, and generates the digest information based on an accumulation result obtained by said statistical processing means.