DVP642 Quick Tip: Adding audio tracks
If you have an existing AVI file that you know works in your player and you wish to add more audio tracks (your own MST3k performance maybe? or perhaps a commentary?), make sure that all your tracks are the same format (MP3 or AC-3) and the same bitrate.
Don’t try to cut corners and reduce the final file size by thinking that you can get away with reducing the bitrate of spoken commentary tracks and the like. The DVP642 requires audio tracks embedded in AVIs to be the same bitrate. Otherwise, not only will it not switch to the secondary tracks, giving you only silence, but it will also not switch back to the original. You’ll have to stop and restart your video to get it back.
So remember, identical formats and bitrates and your player will happily switch between them.
To embed additional audio into an AVI, try D-vision. FFmpegx claims to be able to do it, but that feature hasn’t worked in a while.