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<p class="MsoNormal"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Iam streaming video data via RTSP with gstreamer on a nvidia-jetson board with the following pipeline:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span lang="EN-US" style="font-family:Consolas;color:#525252;letter-spacing:.1pt;background:#F8F8F8">./test-launch -p 8554 "nvarguscamerasrc sensor-id=0 ! video/x-raw(memory:NVMM),width=1024, height=768, framerate=10/1,
format=NV12 ! nvv4l2h264enc ! h264parse ! rtph264pay name=pay0 pt=96"<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:35.4pt"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">When I film the boards “Eigenzeit” from a UART terminal with the camera and compare this filmed time against the received RTP timestamp the received RTP timestamp is 300ms younger than the filmed “Eigenzeit”. At
<a href="https://github.com/GStreamer/gst-plugins-good/tree/master/gst/rtp">https://github.com/GStreamer/gst-plugins-good/tree/master/gst/rtp</a> I read about timestamping on the sender side that this is performed using the following formular:<o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> RTP = ((RT - RT-base) * clock-rate / GST_SECOND) + RTP-offset<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Further reading the README is mentioning this example:<o:p></o:p></span></p>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F">Some pipelines to illustrate the process:<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"><o:p> </o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> gst-launch-1.0 v4l2src ! videoconvert ! avenc_h263p ! rtph263ppay ! udpsink<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"><o:p> </o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> v4l2src puts a GStreamer timestamp on the video frames base on the current<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> running_time. The encoder encodes and passed the timestamp on. The payloader<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> generates an RTP timestamp using the above formula and puts it in the RTP<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> packet. It also copies the incoming GStreamer timestamp on the output RTP<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> packet. udpsink synchronizes on the gstreamer timestamp before pushing out the<o:p></o:p></span></pre>
<pre style="margin-left:35.4pt;background:white"><span lang="EN-US" style="font-size:9.0pt;font-family:Consolas;color:#24292F"> packet. <o:p></o:p></span></pre>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">So if I’m not mistaken this is the reason for the delay of 300ms (= pipeline latency) I’m experiencing. However in my use-case I need a timestamp which is not depending on the pipeline latency. I want to have a timestamp
received via the network that is jitter free and independent of any running time of the pipeline. Is RTP then maybe for my use-case? Or if I can use RTP how I can get the pipeline to produce / generate a RTP timestamp which is independent of the pipelines
runtime?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Thanks in advance for any help on this issue.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Kind regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Steve<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">P.S. Iam not on the mailing list, so please don’t forget to CC: me, thanks
</span><span lang="EN-US" style="font-family:"Segoe UI Emoji",sans-serif">😊</span><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black;background:white">Best regards,</span><span lang="EN-US" style="background:white"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="background:white"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Steve Kreyer<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-----------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Senior Software Development Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">PMC45<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">Vector Informatik GmbH</span></b><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Visitor address: Holderäckerstraße 36 | 70499 Stuttgart | Germany<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Tel.: +49 711 80670-4274 <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><a href="mailto:steve.kreyer@vector.com"><span style="color:blue">steve.kreyer@vector.com</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><a href="http://www.vector.com/"><span lang="EN-US" style="color:blue">www.vector.com</span></a><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt">Registered Office: Ingersheimer Str. 24 | 70499 Stuttgart<o:p></o:p></span></p>
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<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt">Managing Directors: </span><span lang="EN-US" style="font-size:9.0pt">Dr. Thomas Beck, Dr. Stefan Krauß, Thomas Riegraf<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-----------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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