Xubuntu 11.10 - VLC Default Media Player - Thunar
After an install of Xubuntu 11.10 all commercial/encrypted dvds would fail to play. Parole would open and then throw a message saying "could not read dvd. this may be because the dvd is encrypted and a dvd decryption library is not installed".
Even if parole did work I would prefer to have vlc handle my dvd playback. The steps to fix the missing libdvdcss and set VLC as the default DVD player were as follows:
1.) Open up a terminal
2.) Run the below command (Taken from http://medibuntu.org/repository.php) to install the Mediabuntu repository
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 && sudo apt-get --quiet update
3.) Then run
sudo apt-get install libdvdcss2 vlc ubuntu-restricted-extras
4.) VLC should now be installed with dvdcss capabilities.
5.) Now open Thunar (File Manager)
6.) In thunar choose Edit --> Preferences --> Advanced Tab
7.) Click Configure (Below Volume Management) --> Multimedia Tab
8.) Below "Video CDs/DVDs" tick the box "Play video Cds and DVDs when inserted"
9.) In the command box enter the following. I did mess around with trying to use the mounted path /media/DVD_VIDEO but it was not reliable as the path sometimes changes based on the dvd content.
vlc dvd:///dev/sr0
10.) Click close.
11.) Close Thunar preferences.
12.) Insert a DVD and VLC should automatically launch and play the DVD.
Worked for me.

