On the Internet we often do video streaming for example on Youtube, Vimeo, and others. so that firefox 4 on Your ubuntu can stream video, we need to install Flash Player plugin, following the installation instructions.
Add repository “Canonical Partners” as follows
Open Terminal and type :
On Window “Software Sources” will appear, select the tab “Other Software” and put checks on “Canonical Partners”,and then click close.
it is time to update the repository and install Flash Player, type the following command in your terminal:
sudo apt-get update sudo apt-get install adobe-flashplugin
installation is complete, restart your Firefox and perform testing to open streaming video sites like YouTube, Vimeo, and others.