I made my custom filter.
I want to send and receive the user message between UI and my custom MFSource filter.
I researched the MPEG1Source Sample and others...
But, I can't find the way.
You can pass a properset into Source, and change the value in it.
http://social.msdn.microsoft.com/Forums/windowsapps/en-US/39365c13-3468-4130-a8ed-6bad4df231b1/how-to-update-ipropertyset-in-mft