Ubuntu cannot include support for MP3 or DVD video playback or recording. MP3 formats are patented, and the patent holders have not provided the necessary licenses. Ubuntu also excludes other multimedia software due to patent, copyright, or license restrictions, such as Adobe Flash Player and RealNetworks RealPlayer.That doesn’t mean you can’t play .mp3 and other media files in Ubuntu, it just takes a bit of work (not much). Follow these instructions to get mp3, AVI, Mpeg, Flash, etc .. and other multimedia support on your Ubuntu 9.10 (Karmic Koala).
In Ubuntu 9.10 "Karmic Koala", the universe, multiverse and restricted repositories are activated by default.
Run the following in terminal (Applications → Accessories → Terminal), it will add medibuntu repositories in your sources list, It will also adds Medibuntu's GPG key to your keyring, which is needed to authenticate the Medibuntu packages.
$ sudo wget http://www.medibuntu.org/sources.list.d/karmic.list --output-document=/etc/apt/sources.list.d/medibuntu.listNow you can Install non-free-codecs, this will enables your system to support for MP3 and various other audio formats, unrar, Java runtime environment, Flash plugin, Microsoft fonts, w32codecs etc!
$ sudo apt-get -q update
$ sudo apt-get --yes -q --allow-unauthenticated install medibuntu-keyring
$ sudo apt-get -q update
$ sudo apt-get install non-free-codecsYou can install more codecs and DVD Support by using following command, this will help you to run DVDs, AVI files and other mpeg codecs.
$ sudo apt-get install libdvdcss2 libxine1-ffmpeg gxine mencoderNow Install some media players like VLC and Mplayer
$ sudo apt-get install vlc mplayerYou can also install some interesting and useful utilities like Audio Editing Software Audacity
$ sudo apt-get install audacity
