I observed that some people were facing issues while trying to play a Moser Baer (Super DVD) movie DVD on Ubuntu 9.04.
Some times even though all codecs are installed, somehow VLC/totem wont play the DVD. The only suggestion to fix this is to do this:
Go to VLC media player
tools>preferences> videotab
and set the video output to X11 video output.
This *may* help to play those DVDs.
