Comment 2 for bug 209107

Sorry please ignore previous post it's not a problem with the location of defaults.list which should be left alone.
The problem appears to be that nautilus can't find the vlc.desktop entry. If this proves to be the case then there are two possible solutions either Nautilus needs to look in /usr/share/applications/ for .desktop entries or applications need to add a copy of their .desktop entries to ~/.local/share/applications
A simple work around to get VLC to appear as an option in Nautilus > Edit>Preferences>Media>DVD Video you only need to copy the vlc.desktop entry into your ./local/share/applications folder by
<code>$cp /usr/share/applications/vlc.desktop ~/.local/share/applications/vlc.desktop</code>
The copy appears in Nautilus as the entry VLC media player you need to change %U to %m in VLC media player>Properties>Launcher>Command to get DVD's to play automatically. You can now go into Nautilus and select VLC. DVD's should now start automatically when you put them in your computer.