Yeah.
You just ... rip the disc. It's already MPEG.
Actually, you want to use Ulead MUSIC Factory? Why not DVD Factory? I was unaware that music factory lets you build DVD's...
Basically the data on a DVD is MPEG2, you can author multiple titles in many different authoring programs. Perhaps if you explain exactly what it is that you want to do, and which programs you have access to, I could be more helpful...?
- Gurm