How to change default external protocol in Firefox

Generally if you click on a rtsp:// link from Firefox then a popup appear displaying "External Protocol Request" with default player as totem to play that streaming media. But if you want to run a media with RealPlayer or with other software then do the following:

1. Open firefox and type following in the location bar:
   about:config
   
2. Right click any where and select New->String and type following name:
   network.protocol-handler.app.rtsp
   
3. Enter following value if you want to play it with RealPlayer:
   /usr/bin/X11/realplay

Now whenever you will click a rtsp:// media, RealPlayer will appear instead of default Totem player. To check with a media go to http://m.vtap.com and click a video to see it in an action.

How to install RealPlayer in Ubuntu 8.04

I love RealPlayer for lots of reasons. Mainly for excellent streaming support & to pause/resume live media. RealPlayer is free but you will not find it in your Synaptic Package Manager. To install RealPlayer do the following:

1. Visit real player site: http://www.real.com/linux
2. Click "Download RealPlayer" button and save file into your home directory
   
3. Now open terminal and run following commands (I downloaded RealPlayer 11 and it's file name is RealPlayer11GOLD.bin, replace this name with your downloaded file name):
   $ sudo chmod +x RealPlayer11GOLD.bin
$ ./RealPlayer11GOLD.bin
   
4. Installation will start and will ask you to press [Enter]
5. Then it will ask you for installation directory path, press [Enter] if you don't sure about it
6. To finish type F and press [Enter]

That's it. After installation you will find it from 'Applications > Sound & Video' menu.