Ummmm...
I am trying to edit a DVD which Bob has recorded from TV, presumably on a DVD recorder. I guess I'm reverse engineering it into an editable format (mpg), as I don't think .vob files (for that's what they are) are editable, or at least I don't know of a package that does it. This isn't a specialist area of mine!
I can then author it back to being a standard DVD format (vob) and write new discs.
(There are products which allow you to de-protect and de-regionalise purchased DVDs btw). I may have used one in the past

. It was good as you could strip out the menus and trailers, and shrink the remaining film to a standard DVD without significant loss of quality).