Why doesn’t Ubuntu support MP3 ‘out of the box’?

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 files in Ubuntu, it just takes a bit of work (not much).

Follow these instructions to get mp3 and other multimedia support on your Ubuntu 12.04.

Medibuntu (Multimedia, Entertainment & Distractions In Ubuntu ) is a repository of packages that cannot be included into the Ubuntu distribution for legal reasons (copyright, license, patent, etc ) as explained above.

Open the terminal (From 'Dash' ) and type following command to adds Medibuntu's repository to Ubuntu. It also adds Medibuntu's GPG key to your keyring, which is needed to authenticate the Medibuntu packages:

sudo wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list
sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring
sudo apt-get --quiet update

For i386 Users install Codecs using the following command

sudo apt-get install w32codecs libdvdcss2

For amd64 Users install Codecs using the following command

sudo apt-get install w64codecs libdvdcss2

Install mplayer using the following command

sudo apt-get install mplayer smplayer

Mplayer Plugin for Firefox

sudo apt-get install mozilla-mplayer

VLC Media player and plugins:

sudo apt-get install vlc vlc-plugin-pulse mozilla-plugin-vlc

DVD::Rip is a DVD backup/copy program, written in GTK-based perl, that uses the transcode video/audio processing and conversion tools. To install it type:

sudo apt-get install dvdrip

from: http://linuxpoison.blogspot.com/2012/04/multimedia-mp3-mpeg-4-avi-divx-etc.html