I just installed Ubuntu 12.04 on a Dell Inspiron 6400 and tried to enable playing of encrypted DVD's, I made sure libdvdread4is installed and got myself regionset via apt. When I try running it however it tells me
regionset version 0.1 -- reads/sets region code on DVD drives
ERROR: Could not open disc "(null)"!
Please ensure there is a readable CD or DVD in the drive.
I tried this as root, as non-root, with an actual encrypted DVD and also with a "normal" cd with some pictures on it. They both get automatically mounted.
Best Answer
You might need libdvdcss - and you can get that easily. Just follow the instructions here: https://help.ubuntu.com/community/RestrictedFormats/PlayingDVDs
Or, add the Medibuntu repos and install it from there:
sudo -E wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list && sudo apt-get --quiet update && sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring libdvdcss && sudo apt-get --quiet update