1, I would rank Mini DVD and HDD video between 6 and 8 (I can't be more specific than this as different cameras use different compression standards and that affects the result)
as for a demuxing applications there are a couple for pc although i am not sure about mac's. I really don't want to recommend them as they are mostly used to pirate dvd's, and I have seen dodgy copies of them that are full of spyware. Google is your friend.