VLC player is (in my view) by far the most practical and complete DVD player for Ubuntu. There is not one DVD I haven’t been able to play on my computer since I started using VLC.
Recently, however, after a low level clean-up of my Ubuntu packages, VLC player has been showing a very strange symptom: the video is was moving back and forth continuously on a half-a-second slice, while still playing ahead and the sound still being alright.
Anyway, the only way to fix it was to go to the Preferences panel (inside Settings menu), Video, Output modules, tick Advanced options. In the possible options, pick X11 video output (or any other option that fixes the problem for you).
That fixed it for me.