Is there a way to rip an ac3 soundtrack from a DVD and put it into a captured video file then export the new video file to DVD preserving the new ac3 track?

In perticular I want to rip the DD soundtrack from bootleg SW special edition DVDs and edit it into a capture of the original trilogy to put on
DVD.

It seems easy to find bootlegs of the special editions with DD on DVD, but not the originals. I do have the laserdiscs of both versions and would just love to see the originals in 5.1.