private void RtpStream_FirstFrameReceived(object sender, EventArgs ea) { // It is safe to render the graph, because there is a frame available if (sender == rtpStream) { // Creation of the fgm and the adding / removing of filters needs to happen on the // same thread. So make sure it all happens on the UI thread. Conference.FormInvoke(new System.Windows.Forms.MethodInvoker(_RtpStream_FirstFrameReceived), null); } }