Reproduction Apparatus, Video Decoding Apparatus, and Synchronized Reproduction Method

A reproduction apparatus comprising:

• a demultiplexer which separates video data, audio data and caption data from a multiplexed stream in which a video stream, an audio stream and a caption stream are multiplexed;
• a video decoder which decodes the video data;
• an audio decoder which decodes the audio data;
• a caption decoder which decodes the caption data;
• and
• a controller which supplies a synchronization signal for synchronizing with playback of the video to the audio decoder and the caption decoder,
• wherein the video decoder comprises a time stamp calculator which when the multiplexed stream is randomly accessed to playback at any picture, obtains from the video stream a playback time stamp to specify a playback time of a decoded head picture to be first decoded and then calculates a playback time stamp of a display head picture to be first displayed based on the playback time stamp of the decoded head picture;
• and
• wherein the controller supplies the calculated playback time stamp of the display head picture as the synchronization signal to the audio decoder and the caption decoder.

A synchronized reproduction method comprising:

• obtaining from a video stream a playback time stamp to specify a playback time of a decoded head picture to be first decoded, when a multiplexed stream in which the video stream and an audio stream are multiplexed is randomly accessed to playback at any picture;
• calculating a playback time stamp of a display head picture to be first displayed based on the playback time stamp of the decoded head picture;
• and
• decoding and playbacking the audio stream in synchronization with the calculated playback time stamp of the display head picture.

A program which enables a computer to execute:

• obtaining from a video stream a playback time stamp to specify a playback time of a decoded head picture to be first decoded, when a multiplexed stream in which the video stream and an audio stream are multiplexed is randomly accessed to playback at any picture;
• calculating a playback time stamp of a display head picture to be first displayed based on the playback time stamp of the decoded head picture;
• and
• outputting the calculated playback time stamp of the display head picture as a synchronization signal for synchronizing playback of the audio with playback of the video.