Debian Packages: lumiere, w32codecs.
All forms of video viewing is supported by Linux. You can view AVI, DVD, SVCD, and many more codecs (video encodings). Install lumiere and you can view the videos within nautilus. The w32codecs allow viewing of many MS Windows video codecs.
Some packages expect the DVD device to be called /dev/dvd. If it does not exist, and your DVD device is /dev/hdc, for example, then simply:
# ln -s /dev/hdc /dev/dvd