Adding multiple soundtracks
QuickTime has the ability, like a DVD, to include multiple soundtracks and let you select the one you want for playback. Subler is an easy way to add these to your existing movies.
To add a new soundtrack to a movie, follow the steps above to create a project and open the file, then...
5) Select Import->File... from the File menu or click the + button above the track listing in the project window.
6) Use the Open dialog to find the sound file and Open it.
7) Repeat (5) and (6) for each additional soundtrack you want to add.
8) Click on the first track you added, so that the Sound Settings pane appears at the bottom of the document.
9) In the upper pane, select the correct language for the track.
10) In the bottom pane, Select the same "Alternate Group" for each one, typically 1.
11) Repeat (8) through (10) for each of the tracks you imported.
Hint: The first Sound Track in the track list in the upper pane will define the "default" one when opened in QuickTime Player.
Another hint: If you're also adding multiple subtitle tracks, assign them to a different Alternate Group, say 2.