Patent ID: 8042144

Claim:
A method for reproducing additional contents associated with Audio/Video (A/V) data included on a detachable optical disk, the method comprising: determining whether a reproduction mode is an enhanced mode for playing back the additional contents with the A/V data; accessing a server for providing the additional contents associated with the A/V data recorded on the detachable optical disk, and receiving updated information of the additional contents from the server when the reproduction mode is determined to be the enhanced mode, said additional contents not being a replacement or updated version of the A/V data but being information for the A/V data; determining whether an arbitrary file contained in an additional content list associated with the A/V data has been updated, based on the received updated information, the version of the detachable optical disk being a non-hardware version; and making a request for an original file contained in the list or an updated file identified in the updated information according to a result of determining whether the arbitrary file has been updated, and receiving the requested original or updated file, wherein the step of determining whether the arbitrary file contained in the additional content list associated with the A/V data has been updated includes analyzing the received updated information for the arbitrary file and determining a version number of the arbitrary file identified in the received updated information, determining if a latest version of the arbitrary file can be accommodated according to a current version of the detachable optical disk, and if the latest version of the arbitrary file can not be accommodated according to the current version of the detachable optical disk, selecting a next lower version of the arbitrary file to be included in the request, and wherein the step of receiving the requested original or updated file further receives a new synchronization file to synchronize the updated file with the A/V data when receiving the updated file, the new synchronization file replacing an original synchronization file read before a playback operation from the detachable optical disk.