Here is a guide to install the Medibuntu keyring and the ubuntu restricted extras. 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).
The ubuntu restricted extras package will pull in support for MP3 playback and decoding, support for various other audio formats (gstreamer plugins), Microsoft fonts, Java runtime environment, Flash plugin, LAME (to create compressed audio files), and DVD playback.
To install the medibuntu file open a terminal window (press Ctrl+Alt+T) and copy+paste the following lines:
sudo -E wget --output-document=/etc/apt/sources.list.d/medibuntu.list http://www.medibuntu.org/sources.list.d/$(lsb_release -cs).list && sudo apt-get --quiet update && sudo apt-get --yes --quiet --allow-unauthenticated install medibuntu-keyring && sudo apt-get --quiet update
sudo apt-get install app-install-data-medibuntu apport-hooks-medibuntu
To install the ubuntu restricted extras open a terminal window and copy+paste the following line:
sudo apt-get install ubuntu-restricted-extras
When the medibuntu and ubuntu restricted extras are installed you can close the terminal window.