title: gstreamer pipeline with textoverlay via UDP
body: <p>I would like overlay my rtsp stream by dynamic text.</p>
  <p>I try to change text via udp.</p>
  <p>It work, but text is displayed only half second.</p>
  <p>Problem is (in my opinion) that timestamp and duration is not set.
  Because if you link some element to text_sink - incoming text is parse like subtitle...
  Is there any option how to fixt it? (use some queue?? subparse - not working as well)</p>
  <p>gst-launch-1.0 -e  <br />
  rtspsrc location=rtsp://192.168.100.251:554/Streaming/Channels/102  !<br />
  rtph264depay ! h264parse ! decodebin !  queue !  textoverlay name=poutext wait-text=false  ! autovideosink <br />
  udpsrc port=1234 ! poutext.text_sink</p>