Hi Simon I have attached trace file for 4cif transmission with my application running on both sides for debugging. Trace level is set to 5. I have added capabilities as videoWidth = 704; videoHeight = 576; DisableFastStart(1); DisableH245Tunneling(1); AddAllCapabilities(0, 0, "*"); SetVideoFrameSize(H323Capability::cif4MPI); Please suggest. ----------------------------------------------------------------- Get your free Email ID at www.zapakmail.com now!