I have the exact same problem. I rip to the generic h264 mp4 format. Some movies are OK, others have the problem every time no matter what options I change:
It's super annoying to see someone's lips move and hear their voice half a second later. It does seem to get progressively worse as the movie goes on.
I hate having to go through my ripped movies and watch each one closely to determine which I have to rerip. I wish it would just work the first time. NOTE: the above movies it happens EVERY time I rip them. I can find a crap ton more to add to the list, these are just the most recent.