We're having the same problem converting our virtual camera to an extension - nothing we tried works as a way to communicate from the host application to the extension. I would assume that a full sample would be coming along at some point, but it's frustrating to get the extension template "working" quickly, then have no way to go from there to something useful.

@ldeoue, I think an example of sending the frames from the app to the extension's sink stream would be very helpful.

Well, it's an example of setting up the sink stream. It doesn't do anything with it yet - I'm still working that part out.