Here's how you can install the restricted extras in Ubuntu 14.04.
1. Open a terminal window.
2. Type in the following command then hit Enter.
sudo apt-get install ubuntu-restricted-extras
There are some Restricted extras available in Ubuntu repositories which can't be install while installation but you can install these Restricted extras by yourself. Restricted extras contains: mp3 playback and decoding, support for various formats, fonts, java, flash plugin, lame...More at Noobs Lab
Additional Ubuntu Resources