How to demux VOBs

[Vejita-sama]

I'm trying to back up a DVD-9 with four 45min PCG. I want to create a new set of VOBs with only two PGC (to fit on a DVDR). Here's what I'm planing to do:

1) Rip DVD
2) Use IFO edit to create new IFO/VOBs for each PGC
3) Demux new files to m2v/ac3
4) Load two m2v/ac3 at a time in maestro, re-complie
5) Burn

This way I'll get two titles (to easily switch between each PGC without making a menu) and the chapters remain intact.

The problem is I can't figure out how to demux the IFO edited files into one m2v/ac3 stream. I have to either demux each VOB and generate 2-4 m2v files, or burn the files to a DVD-RW and then use DVD decryter to demux w/ streams enabled.

I know there has to be an easier way then this

Q: How can I take a DVD with four PGC of 45min each, and create a new DVD with only two 45min PGC (or two movies/titles).

Thanks in advance

[sunmiztres]

use vobedit to demux, works like a charm