It's going to be tough to discuss this subject without running afoul of Rule #1 as most DVD rippers are designed to defeat CSS encryption protection and thus violate the DMCA (and trigger Rule #1). You'll find that most rippers are hosted in China or other places with a casual attitude to the US DMCA.
IOW, if you're about to suggest a program that can remove CSS protection, stop right there so I don't have to mod your post.
Thanks for listening.
If the Earth were flat, cats would have pushed everything off of it by now.