reduce latency

raspberry/roberto/camera/camera_gstreamer_webrtc.py

@@ -130,6 +130,9 @@ class WebRTCCamera(Thread):
         webrtc.connect('on-negotiation-needed', self.on_negotiation_needed, client_sid)
         webrtc.connect('on-ice-candidate', self.on_ice_candidate, client_sid)
 
+        rtpbin = webrtc.get_by_name('rtpbin')
+        rtpbin.set_property("latency", 40)
+
         if platform == 'raspberry':
             rpicamsrc = pipe.get_by_name ("rpicamsrc")
             #rpicamsrc.set_property("annotation-mode", 1)