Mux AVI and MP3 on the fly for playback

[osullic]

I generally back up my DVDs to Xvid-encoded AVIs using DVD Decrypter and Auto Gordian Knot.

If a DVD has director's audio commentary, I'd like to back that up too.

I'm just wondering if there's a way to do this without making two separate AVIs, one with the standard movie soundtrack and the other with the director's commentary, but with both having the same video stream duplicated across the AVIs.

I know I could rip the video and audio streams separately and encode to AVI and MP3 respectively, but is there any player that could "mux" these back together "on the fly" for playback (without doing something primitive like trying to manually synchronise the MP3 playing on one player with the AVI playing on another player)?

I suppose even if this is possible, I'd probably need to have the two AVIs with duplicated video streams anyway, if I ever wanted to watch the movie on a portable media player.

Any thoughts on this?
Thanks

[sneaker_ger]

In Media Player Classic's "Open File" menu you can specify another audio file as an additional audio track.

[Inspector.Gadget]

You can make an AVI with both audio streams included, but the better option might be to use Matroska instead.

[osullic]

Thanks for the helpful replies. I like the suggestion of loading the additional audio track in Media Player Classic. I didn't have it installed as I usually just use VLC Media Player, but I gave it a shot and it does exactly what I wanted.