How to install Multimedia Codecs

      sudo aptitude install ubuntu-restricted-extras libxine-extracodecs gstreamer0.10-plugins-base gstreamer0.10-plugins-good \
     gstreamer0.10-plugins-bad gstreamer0.10-pitfdll

The "ubuntu-restricted-extras" is a meta-package that installs : flashplugin-nonfree, gstreamer0.10-plugins-ugly, gstreamer0.10-plugins-ugly-multiverse, msttcorefonts,sun-java6-jre and sun-java6-plugin Important note: that w32codecs are copyright infrigement since they are basically exact copies of DLLs that are shipped by various Windows software to handle media formats.

     sudo aptitude install w32codecs

Note to Kubuntu Users: Technically the only packages needed for Kaffeine to play extra codes are libxine-extracodecs and w32codecs. However the installation of all the above packages doesn't hurt anything, as these packages might be needed by other programs (e.g., Open Office Impress uses a gstreamer plugin to display video in presentations).