install multi-media codecs

You may need to install multi-media codecs to enable previewing movies. Press Ctrl+Alt+T to open terminal. When it opens, run below commands to install media codecs:

sudo apt-get install gstreamer0.10-plugins-ugly gstreamer0.10-ffmpeg libxine1-ffmpeg gxine mencoder libdvdread4 totem-mozilla icedax tagtool easytag id3tool lame nautilus-script-audio-convert libmad0 mpg321 gstreamer1.0-libav

Install Codec – Kodek MP3 di Ubuntu

$ sudo apt-get install ubuntu-restricted-extras

Install Flash Player For Ubuntu Linux

Type the following command to install flash player:
$ sudo apt-get install flashplugin-nonfree