A data processing apparatus is provided. The data processing apparatus includes a plurality of ports, a memory, a determining unit, and a processing unit. The plurality of ports are configured to input and output video data. The memory is configured to store the video data when the video data is recorded onto a recording medium and when the video data is played back from a recording medium. The determining unit is configured to determine whether video data, for which a video data playback request designating one of the plurality of ports has been issued, is stored in the memory, using data identification information for identifying video data and usage management information. The processing unit is configured to have the video data stored in the memory outputted from the designated port, when the determining unit determines that the video data is stored.