<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hi,<br class=""><br class="">I am working on a python app that turns an rtsp stream from a networked camera into a stream that you can access through the browser via WebRTC.<br class=""><br class="">For that, I am using a dynamic pipeline, the rtp audio and video streams go to a fakesink through a tee element. For each incoming websocket connection, I build an WebRTC connection: I am adding two queues, one for audio, one for video to the tee elements and connect them to a new WebRTC element. Then I exchange the SDP offer and response via websockets.<br class=""><br class="">Now, in some situations, after quick reloads of the web page that brokers the connection, the newest added WebRTCBin element does not send the “on-negotiation-neeed” signal. I am assuming this is because it did not receive caps on the newly requested pad, thus the gst_webrtcbin_sink_event method did not get triggered and the WebRTCBin is not checking whether a negotiation is needed. <br class=""><br class="">A PDF of the pipeline is here: <a href="http://roettsch.es/debug_gst_webrtcbin.pdf" class="">http://roettsch.es/debug_gst_webrtcbin.pdf</a> and an image of the relevant portions is attached.<br class=""><br class="">The WebRTCBin element sendrecv-2-772371 has blocked pads, as it hasn’t done any negotiation and unblocked its pads, but also the CAPS on the links to the queue elements only show “ANY”.<br class=""><div class=""><br class=""></div><div class="">I have a few questions to further investigate this:</div><div class=""><br class=""></div><div class="">What could be the reason the caps event is not received by the GstWebRTCBin?</div><div class="">When is the caps event usually sent downstream? Is it sent only once and could it be that the GstWebRTCBin somehow missed it through some race condition?</div><div class="">When connecting queue and webrtcbin to the tee element, do I need to follow a certain order? Do I need to insert probes in order not to miss the caps event?</div><div class=""><br class=""></div><div class="">Thanks for your help,</div><div class=""><br class=""></div><div class="">Dominik</div><div class=""><br class=""></div><div class=""><img apple-inline="yes" id="19A00033-B389-4D03-81F0-8C5B6EF1C428" width="320" height="197" src="cid:D3563E20-8B81-48D3-AB6E-D9FEDD9198C1@ipv6.drwebdesign.de" class=""></div></body></html>