A transmission server reads out encoded data files from storage medium such as memory in itself and removable medium, and transmits the read-out file to the reproduction apparatus upon the request from the reproduction apparatus. A plurality of encoded video files are corresponding to an AV content. These encoded data files correspond to different reproduction modes respectively. The transmission server transmits an encoded file to the reproduction apparatus which corresponds to the requested AV content and the requested reproduction mode. Further, the transmission server switches files to be transmitted based upon a mode switching request from the reproduction apparatus. In other words, the file to be transmitted is switched from an encoded file corresponding to a pre-request reproduction mode to another corresponding to a post-request reproduction mode.