Adding Alternate Video Streams
One feature unique to the DVD medium is the viewer’s ability to switch between parallel
video streams with continuous audio. Only one video stream at a time can serve as the
active stream, but there can be as many as eight alternate streams, for a total of nine
“camera angles.” These can be different camera views, or angles, of the same subject, or
they can be any other video sources.
For example, a concert video could use different camera angles for the alternate video
streams, with cameras focusing on each musician. Stream V1, the main video stream,
could be an edited version of all angles while streams V2 to V9 could be unedited versions
of each musician. This would allow the viewer to choose whether to see the whole concert
or focus on a specific aspect of it.
In another example, the V1 stream could contain the normal view of a business
presentation, including the presenter, and the presentation’s slides could be displayed
up close on the V2 stream.