title: how to enable transport wide congestion control in gstreamer
body: <p>I am developing an application that streams h264 video with gstreamer using RTP and RTCP in c++. The video stream is successfully received and both the sender and receiver is generating SR/RR RTCP packets. My next goal was to utilize twcc (transport wide congestion control) for bandwidth management, which should be supported in gstreamer since version 1.18. I can not however figure out to enable this feature. My pipeline looks similar to this:</p>
  <p><code>appsrc ! videoconvert ! h264enc ! rtph264pay ! rtpbin ! udpsink -&gt; udpsrc ! rtpbin ! rtph264depay ! avdec_h264 ! videoconvert ! autovideosink</code></p>
  <p>The rtpbin also has the appropriate RTCP pad links with its own udpsrc and udpsink on both sender and receiver side (not shown here).</p>
  <p>As i understand twcc i need to set the appropriate rtp header extension, but i cannot figure out how to do that using gstreamer. I am also unsure how to make the recevier side send back the correct rtcp packets so that i can read the twcc-stats on the sender side.</p>
  <p>Does anyone have an example on how i would make my gstreamer pipeline start using twcc?</p>