MPlayer utilizes a complex playtree. It consists of global options written as first, for example

mplayer -vfm 5

and options written after filenames, that apply only to the given filename/URL/whatever, for example:

mplayer -vfm 5 movie1.avi movie2.avi -vfm 4

You can group filenames/URLs together using { and }. It's useful with option -loop:

mplayer { 1.avi -loop 2 2.avi } -loop 3

The above command will play files in this order: 1, 1, 2, 1, 1, 2, 1, 1, 2.

Playing a file:

mplayer [options] [path/]filename

Playing more files:

mplayer [default options] [path/]filename1 [options for filename1] filename2 [options for filename2] ...

Playing VCD:

mplayer [options] vcd://trackno [-cdrom-device /dev/cdrom]

Playing DVD:

mplayer [options] dvd://titleno [-dvd-device /dev/dvd]

Playing from the WWW:

mplayer [options] http://site.com/file.asf

(playlists can be used, too)

Playing from RTSP:

mplayer [options] rtsp://server.example.com/streamName

Examples:

mplayer -vo x11 /mnt/Films/Contact/contact2.mpg
mplayer vcd://2 -cdrom-device /dev/hdc
mplayer -afm 3 /mnt/DVDtrailers/alien4.vob
mplayer dvd://1 -dvd-device /dev/hdc
mplayer -abs 65536 -delay -0.4 -nobps ~/movies/test.avi