Most commercial DVDs are encrypted with CSS (the Content Scrambling System), which attempts to restrict the software that can play a DVD. The libdvdcss2 package will enable you to play such disks. Unfortunately, bypassing encryption schemes may be illegal in your country. If you still do intend to pursue such a course, please send me a hand-made postcard from jail. I will add it to my collection of victims of uncaring governments that have their hands out to commercial interests.
To potentially flaunt the law, install the libdvdread4 package via Synaptic. Then from a terminal,
sudo /usr/share/doc/libdvdread4/install-css.sh"Note that if your DVD player regularly locks up when you try to play back a DVD, your DVD player probably does not have the right geographical region set. If region 1 is set, you can play DVDs bought in the US, but not in Japan. Unfortunately, you can only change the region code five times on most DVD players, so don't try to routinely play DVDs bought in different regions. Even if you use US DVDs only, your player may have the wrong, or no region code set. The regionset tool can fix that."
However, I had none of the above trouble with the build-in player and US-bought DVDs.
With or without libdvdcss2, you want the VLC player. From synaptic, install package vlc. You should also install vlc-plugin-esd and mozilla-plugin-vlc.
Other packages that I installed are supposed to provide capabilities to play back a variety of formats:
To play a movie DVD, insert the disk and select the VLC player when prompted, or start the VLC player from the menu and then use File/, Disk/, browse to the DVD, and press Play.
Note: I found that volume may be so low that it appears that there is no sound. I just played a DVD in which I initially assumed there was no sound at all. I had to turn VLC volume, computer volume, Volume Control/ PCM, and the volume knob on my speakers to the max to get a decent volume. (I do not usually play movies on my computer but the change to digital broadcasting seems to have burned out my Sony TV. The TV powers down after a couple of seconds every time I turn it on, both the TV and me making funny sounds. No, it does not ask permission to power down. And it is not asked to display broadcast TV channels, just DVDs. Yes that was Sony.)