Since I didn’t have any luck playing videos on the RPi using mplayer I found omxplayer after some search. It has the ability to use the RPi’s GPU thus taking some load of the CPU.
UPDATE 2013-04-01: omxplayer is now included in the Raspbian (Debian Wheezy) repositories and can be simply installed by one line.
sudo apt-get install omxplayer
Check another article on how to install Raspbian.
OMXPlayer binary (.deb) downloads can be found here: http://omxplayer.sconde.net/
apt-get install libpcre3 fonts-freefont-ttf fbset libpcre3-dev libpcrecpp0 libva-dev libva-x11-1 libva1
dpkg -i omxplayer_0.2.4~git20121205~ec7ac68f_armhf.deb
omxplayer -o hdmi video.mp4
Note: If there is no sound when playing through the HDMI interface make sure your /boot/config.txt file has the following line (and it’s not commented out).
hdmi_drive = 2
OMXPlayer Key bindings
|j||Previous Audio stream|
|k||Next Audio stream|
|n||Previous Subtitle stream|
|m||Next Subtitle stream|
|Space or p||Pause/Resume|