Mplayer is a media player, its mainly used to play audio or video.
What I like about it is how you can use it in the command line.
For example to play a audio file.
Its as simple as that.
For a video its slightly different. Mplayer does not support dvd menu's which is a bit of a pain really so you need to do the following
obviously title number needs to be replaced with your desired title number. Xine is a lot better for DVD menu's but that's a whole other kettle of fish
If you wish to move forward in a track or film there are a whole load of keyboard short cuts available here
I know your thinking "what's the big deal?" but the real reason I use mplayer is to rip audio from video files.
I use this a lot in conjunction with the youtube-dl program.
mplayer -ao pcm -vo null -vc dummy -dumpaudio -dumpfile someVideo nameOfAudioFile.mp3
I've taken the liberty off adding a selection of commands below:
Play all files in directory
$mplayer -playlist <(find "$PWD" -type f)
Stream Youtube directly to mplayer
$yt () mplayer -fs -quiet $(youtube-dl -g "$1")
use mplayer to play just the audio from a video
mplayer -vo null something.mpg
Shuffle songs in mplayer with no output
mplayer -shuffle $HOME/music/* $HOME/Dropbox/Music/*/* $HOME/Dropbox/Music/*/*/* etc. >> /dev/null 2>&1