title: GStreamer: Add dummy audio track to the received rtp stream
body: <p>I'm initiating RTP stream from my Raspberry camera using:</p>
  
  <p><code>raspivid -n -vf -fl -t 0 -w 640 -h 480 -b 1200000 -fps 20 -pf baseline -o - | gst-launch-1.0 -v fdsrc ! h264parse ! rtph264pay pt=96 config-interval=10 ! udpsink host=192.168.2.3 port=5000</code></p>
  
  <p>on the client site, I'm converting it to HLS and upload it on a web server:</p>
  
  <p><code>gst-launch-1.0 udpsrc port=5000 ! application/x-rtp,payload=96 ! rtph264depay ! mpegtsmux ! hlssink max-files=5 target-duration=5 location=C:/xampp/htdocs/live/segment%%05d.ts playlist-location=C:/xampp/htdocs/live/playlist.m3u8</code></p>
  
  <p>the above works with me. on the other hand some players does not play the HLS since it has no audio track. I'm trying to figure out how i can add a dummy audio track. I tried many things but no luck e.g. </p>
  
  <p><code>gst-launch-1.0 udpsrc port=5000 ! application/x-rtp,payload=96 ! rtph264depay ! h264parse ! mux. audiotestsrc wave=4 freq=200 ! audioconvert ! queue ! mux.    mpegtsmux name=mux ! hlssink max-files=5 target-duration=5 location=C:/xampp/htdocs/live/segment%%05d.ts playlist-location=C:/xampp/htdocs/live/playlist.m3u8</code></p>
  
  <p>or </p>
  
  <p><code>gst-launch-1.0 -e -v udpsrc port=5000 name=src ! application/x-rtp,payload=96 ! rtph264depay ! h264parse ! mpegtsmux name=mux ! audiotestsrc wave=silence src. ! audioconvert ! wavenc ! rtpmp4gdepay ! aacparse ! mux. ! hlssink max-files=5 target-duration=5 location=C:/xampp/htdocs/live/segment%%05d.ts playlist-location=C:/xampp/htdocs/live/playlist.m3u8</code></p>
  
  <p>Any help is appreciated</p>