I have a nice copy of an Old and in the Gray on DVD but it has crappy cam audio. I just found the sole SBD audio source and want to re-author the DVD. I figured out that I could rip the audio off the DVD using DVD Decrypter and use a Wavelab montage to sync up the old audio with the new audio, trim and render.
My question is what is the best way to get the video off of the DVD? Isn't DVD audio already compressed? Should I just rip it off in MPEG2 and then use something like Vegas or tmpegenc to mux the two back together?
I know that this is a little bit of re-hash because I searched and found a couple of links. I could use a good workflow though.
This is very tricky business. Reason being - you can virtually guarantee the video and new audio source will not be the same speed - meaning that the synch is never more than one frame (1/30th of a second) off.
If you want to keep the original video - it's a very simple process: just demux it from the DVD using DVD Decrypter (mode = ifo, in the "input" box, highlight the file, click on "stream processing," declick the audio box, click on the video portion and highlight it, and then click the "demux" box at the bottom). If you're positive they are in synch, you can drop them in TMPGenc or a "smart mpeg editor" and mux them.
If you need to get them in synch... I don't know of any NLEs (such as Vegas) that will accept mpeg2 files, so you're probably stuck with using a "smart mpeg editor" such as Womble. It's a great program, but smart mpeg editors can really be hard to work with for such things because you have to be so precise (within 1/30th of a second) with the synching - and these programs are not good for doing this (hard to explain why - but if you try using one - you'll know what I mean). And in this case, you're probably not going to be working with video and audio that are the same speed.
My recomendation - do an analog capture of the DVD using your DVD player to capture the video to your harddrive. Yes - it will require re-encoding and a slight loss in video quality. But the only way you really have a chance at getting this video and audio to match up is by doing it in an NLE like Vegas.
Capture the video and audio from the DVD to the HD. Drop the SB audio on a second audio line. Compare the differences in audio lengths between the two (you might want to do this one song at a time), right click on the SB audio track, in the "time stretch/pitch shift" method box click "classic," enter in the new length for the SB audio, and click OK. You'll have to tinker with it, but you should be able to get it in synch. You might have to do some "micro splices" of one frame here and there to really get it matched up perfectly.
Lastly - don't assume the cam audio is perfectly in synch with the video. It all depends on how far the cam was from the sound source. If it was far away, it will be out of synch also. So the key is to make sure the SB actually matches with the video. But of course, the cam audio will be very close (if not perfect), so it will always be a great guide.
Good luck.