You go visit your favorite movie preview Web site to watch a video clip only to discover that it is in Quicktime or Microsoft media format and that it doesn't work in your browser. I mentioned the Crossover Plugin as a solution, but you can use your MPlayer for viewing those clips as well.
You do this by using the mplayerplug-in, an open source plugin that uses Mplayer. Head over to http://mplayerplug-in.sourceforge.net/ and download the latest source (RPM packages for RedHat are also availble there). If there are no packages available for your distribution and you need to build from source, have no fear. It's easy.
tar -xzvf mplayerplug-in_v0.80.tar.gz cd mplayerplug-in make make install
What the last line really does is copy the resulting mplayerplug-in.so file into your home directory's .mozilla/plugins directory.
cp mplayerplug-in.so $HOME/.mozilla/plugins
If you want to make the plugin globally accessible, you'll need to know Mozilla's system-wide plugins directory (or Netscape's). For example, with my RPM-installed Mozilla, I would use this command:
cp mplayerplug-in.so /usr/lib/mozilla/plugins
I'm sure you are more than ready to try this out and you could do so with Mozilla immediately. Start Mozilla, and surf on over to your favorite movie preview site (I tend to like Apple's site for the latest trailers, http://www.apple.com/trailers). When you click on a movie clip to view, a window will appear in the browser with the words "mplayerplug-in ? Loading movie …"
Sit back and enjoy the show.