I have installed Ubuntu Mate 15.04.
When I insert an audio CD or a non-commercial DVD into the drive a window will appear asking me what I want to do. I know how to change the settings to cause the disk to automatically play with a particular program (e.g. VLC).
However, when I insert a encrypted DVD into the drive this window does not appear.
I am, however, able to open VLC and play the encrypted DVD without any problems so I am sure that all the software needed to actually play the DVD is installed.
There is a message in /var/log/syslog stating “Read of scrambled sector without authentication”.