[MacDV] Making changes to a VIDEO_TS

[whoisquilty]

I've got a couple of DVDs that were homemade by another person but I'd
like to modify them. They are extremely complicated with
feature-specific chapters, subtitles, and stories. But, I'd like to
remove some of the features and add others, going from a single-layer
to a dual-layer disc.

Is there a way to do this? If it would be easier to rip the material I
want to use from the disc, are there utilities for ripping chapters
and stories?

Thanks for any help.

Jer