I think you know it, but just to be sure... Do you wait after calling self.pipeline.set_state(Gst.State.PLAYING)? This is not a blocking call and the program will exit immediately. -- View this message in context: http://gstreamer-devel.966125.n4.nabble.com/Strange-behaviour-tp4680980p4680992.html Sent from the GStreamer-devel mailing list archive at Nabble.com.