Some popular programs to play DVDs are mplayer, Xine and VLC. Xine and VLC support dvd menus where mplayer will play any title you specify.
You might need to add your user to the group optical to be able to access your dvd drive:
gpasswd -a USERNAME optical
You will of course need to install the libdvd packages if you want to play encrypted DVDs
#pacman -S libdvdread libdvdcss libdvdnav
Mplayer is efficient and not heavy on the system requirements. There isn't much that can't be played with this program. To play a DVD with mplayer
Where N is the chapter that you want to play, start at 1 and work your way up if you are not too sure. To play a dvd image file
mplayer -dvd-device movie.iso dvd://N
To play a loopback mounted image (shouldn't be needed, use the above)
# as root mount -o loop movie.iso /mnt/dvd # as a user mplayer -dvd-device /mnt/dvd dvd://N
To find your audio language you can start mplayer with the -v switch and it will output audio IDs. You can make use of any auido track with -aid <audio_id>. You can set a default audio language by editing ~/.mplayer/config and adding the line alang=en for english.
DVDs can have volume too low. To increase the maximum volume to 400% use softvol=yes and softvol-max=400. The startup volume defaults to 100% of software volume and the global mixer levels will remain untouched. Using the 9 and 0 keys, volume can be adjusted between 0 and 400 percent.
alang=en softvol=yes softvol-max=400
The GUI version of mplayer is not quite as powerful as the console version but still efficient.
A good GUI player which works quite well on slower computers which supports menus.
A capable player which supports menus, installed with
pacman -S vlc
Backing up Video
See Make backup of DVD Video or use k9copy or dvdshrink under wine for the easy way out.
See DVD writing.