Hello everybody. You’re trying to watch a DVD but it is not working even after you have installed the restricted packages like shown in Installing codecs of audio, video, Flash and also installing Java in Ubuntu.
There is a possibility of its being encrypted DVD with CSS (Content Scrambling System). When you installed the restricted packages, the libdvdcss2 was not installed. So, to solve that, open a terminal and run:
sudo apt-get install libdvdread4
That’s it. See you next time.