Media files on computers are usually encoded in order to reduce the size of the file (raw video/audio files are HUGE!). What does this encoding magic is something called a 'codec', or 'compressor-decompressor'. The version of MPlayer that ships with the EEE can play quite a few different types of movie and audio files thanks to the codecs that are built into it. But there's something called a 'codec pack' that the MPlayer developers put together in order to be able to play many more files. The 'codec pack' contains a bunch of different libraries, including Windows .dll files, that allow MPlayer to play many more video files than the default version that's on the EEE. There's an easy way to add this 'codec pack' to your machine…

Editted 2009/08/04 If you only want to play .rmvb movie format you could skip to the last part where it says “Play .rmvb video format.” I am not sure if .rmvb is covered on the “Adding the Codec Pack.”

1. Make sure you're connected to the Internet. The codecs will be downloaded automatically from a mirror site (the script you will run will choose a mirror automatically)
2. Open a terminal window by hitting Ctrl-Alt-t
3. In the terminal window, type sudo /usr/share/mplayer/scripts/binary_codecs.sh install
4. Wait a few seconds to a few minutes, depending on the speed of your connection
5. Once the install is complete, go find your favorite video clip or movie file and try to play it!

If the video file you play still has no video output in the Media Player application, try playing it on the command line. MPlayer is very verbose when it tries to play a file, it will tell you which codec it's missing. Then, you can either go look for the codec, or go look for help finding the codec by going to the EEE forums

mplayer /path/to/some/movie/file.avi

Yes, the h264 codec is missing from the version of MPlayer that comes with Xandros/EEE PC. There is a way to get it back, but it involves 'downgrading' MPlayer to a version that has that codec (and a lot of other missing codecs) installed.

(based on notes from this forum post)

It's recommended that you read the page on adding Xandros software package repositories so you have an idea of what's going on and what you can do to your system. Basically, you will be installing an older version of a software package that exists on your EEE, and there may be problems because of it. It's recommended that you add the 'package pinning' stuff listed on that page to /etc/apt/preferences as well.

If you still want to do this…

1. Open a terminal window by hitting Ctrl-Alt-t
2. Type sudo kwrite /etc/apt/sources.list
3. Add the following to the file: deb http://archive.debian.org/debian etch main
4. Save the file
5. Back in the terminal, type: sudo aptitude update
6. Then type: sudo aptitude install mplayer=1.0~rc1-12etch7

(Hint: you can copy and paste this text from Firefox into the Terminal; highlight text in Firefox using the mouse, Ctrl-C, paste into a terminal by clicking on the terminal window and tapping TWO fingers on the touchpad)

You are specifying that an older version of MPlayer should be installed from the archived etch repository; the version number and repository shown above worked as of 23Sep2011, but could change in the future. Try increasing the number after etch.

Note: This is tested on eee 900 in default Linux OS without any modification done on smplayer or mplayer.(In short I didn't do any process above.)

• download the codecs and save it on home or /home/user/ (if your picky then anywhere). I downloaded Linux x86 20071007 and saved it on /home/user/.
• Right click on the file, in my case essential-20071007.tar.bz2, and Extract All. It should show essential-date on the extracted folder.
• Open a terminal(ctrl-alt-T) and enter these codes (enter after every line)

  cd /home/user/essential-date
  sudo mkdir /usr/lib/codecs/
  sudo cp * /usr/lib/codecs/

• Your done! now you need to double click the .rmvb file to play.

Note: .rmvb file will not associate automatically with smplayer or mplayer so you would still have to double click the .rmvb file, then a window with a list of “Known Application” and navigate through Application-Multimedia-Smplayer to play.