Ubuntu 9.04 Required the foll0wing steps to Run Multimedia files like MP3, AVI, Mpeg, Flash file etc...
In Ubuntu 9.04 "Jaunty jackalop", the universe, multiverse and restricted repositories are activated by default.
For installing Multimedia files you need to add medibuntu repositories.
Run the follwing in command mode it will add medibuntu repositories in your sources list
$ sudo wget http://www.medibuntu.org/sources.list.d/jaunty.list --output-document=/etc/apt/sources.list.d/medibuntu.list
then Add the GPG Key:
$ sudo apt-get update && sudo apt-get install medibuntu-keyring && sudo apt-get update
Run
$ sudo apt-get update
Now you can Install non-free-codecs
$ sudo apt-get install non-free-codecs
It will enables your system to support for MP3 and various other audio formats, unrar. Java runtime environment, Flash plugin, Microsoft fonts, w32codecs etc!
You can install more codecs and DVD Support by using
$ sudo apt-get install libdvdcss2 libxine1-ffmpeg gxine mencoder
It will help you to run DVDs, AVI files and other mpeg codecs.
Now Install Famous VLC player and Mplayer
$ sudo apt-get install vlc mplayer
You can Install following interesting and useful utilities
Audio Editing Software Audacity
$ sudo apt-get install audacity
Adobe Acrobat Reader
$sudo apt-get install acroread acroread-plugins