Debian Multimedia Repositories
For those who enjoy watching movies and listening to various audio files in Debian-based Linux distributions, there is an awesome project out there called Debian Multimedia. It offers many codecs and other useful applications and libraries that are required to work with a lot of different multimedia formats. This is how you may setup your computer to use Debian Multimedia as a repository. This allows you to quickly and easily install the things you need to get up and running.
Note: Some of these packages contain things that are protected by copyright, and you need to be aware of the laws and implications of installing them on your system wherever you may live. It may or may not be against the law.
Download the keyring from http://www.debian-multimedia.org/pool/main/d/debian-multimedia-keyring/debian-multimedia-keyring_2007.02.14_all.deb. The keyring is simply a package that includes an authorization key to ensure the server is who it says it is.
Install the keyring. Downloading the keyring is not enough. Now you have to tell your system to use it. One way of doing that is to run the following command as root (or with root privileges) in the directory where you downloaded the keyring:
dpkg -i debian-multimedia-keyring_2007.02.14_all.deb
This will copy the keyring to the appropriate place on your computer so apt-get won't complain when it tries to access debian-multimedia.org
Install the repositories. This part usually depends upon your particular flavor of Debian. I am running Debian Sid, so I install the Debian Multimedia repository using the following line:
deb http://www.debian-multimedia.org sid main
If you are running Debian "etch", you would change sid to etch and likewise for other flavors of Debian. This line typically goes in the /etc/apt/sources.list file. Just put it on its own line. Some newer Debian systems prefer that you put this line in /etc/apt/sources.list.d/[repository].list (where [repository] would likely be debian-multimedia in this case).
Run apt-get update as root to make sure the repositories are working properly. If they are, you should see no errors or warnings pertaining to debian-multimedia.org. If you see any such messages, try updating again.
And that should get you rolling! Good luck.