Do have filter DirectShow source filter for rtsp protocol   

I have the experience of writing a source filter for a local file.
But how to write a source filter that will be invoked when the user
type
"rtsp://xxx" in "File->Open URL"? What should be the media type?
Is there any sample code? 
Thanks.

date: 13 Jul 2005 02:08:54 -0700   author:   unknown