Ubuntu fix DVDs playing

Some movie DVDs don't play regardless the used player: vlc, mplayer, gxine, movie player, etc. This fixes it:

sudo apt-get install libdvdread4

sudo /usr/share/doc/libdvdread4/install-css.sh

Source for info: https://help.ubuntu.com/community/RestrictedFormats/PlayingDVDs

Error received: "error reading nav packet"