Audio and Subpicture Streams

A DVD-Video disc can have up to eight audio streams, numbered zero through seven, each with up to six discrete channels. Only one of these streams can be active at any given time. For subpictures, up to 32 streams are available, numbered 0 through 31, although for audio only one stream can be active at any given time. Discs are generally authored with default audio and subpicture streams, but an application can enable the user to see all the streams that are available for a given title, and select the one in the language they prefer. The basic steps in this process are the same for both audio and subpicture streams:

1. Determine the number of streams available for a specified title.
2. Iterate through the streams and retrieve the stream attributes for each.
3. Retrieve the language code from the returned locale identifier (LCID) and create a human-readable string.
4. Populate a "Select" box or other user interface control to enable the user to select the preferred stream.

(Note that audio and subpicture streams are numbered from zero, whereas titles, angles, and parental levels are numbered from one.)