Audio, Video, and Subpicture Data

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A DVD-Video recording is an MPEG-2 program stream composed of multiple elementary streams for video, audio, and subpicture data. These elementary streams have the following properties:

  • A single video stream provides all the video content for the recording. The video stream contains line 21 Closed Caption data, if any exists.
  • There can be up to eight separate audio streams, or tracks, providing up to eight multichannel soundtracks.
  • There can be up to 32 subpicture streams containing bitmap graphics used for menu buttons and subtitles. The subpicture data streams are independent of the Closed Caption data in the video stream, although they may look similar when they appear in the video rectangle. If a disc contains both subpicture and Closed Caption data, you cannot display both at the same time.

The ability to present multiple angles, giving the viewer the ability to view a scene from up to nine different camera angles, can give the impression that a DVD-Video recording contains more data streams than those listed above. Angles are authored with interleaved video objects, each of which contains cells that are full MPEG-2 program streams. During playback for a given camera angle, a single coherent MPEG-2 stream is assembled from a specific subset of the interleaved VOBs. This single stream has all of the stream properties listed above. Only one angle can be active at a time during playback.

 Last updated on Thursday, April 08, 2004

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