<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">OK, as I thought...<div class=""><br class=""></div><div class="">In order to bring the discussion back from the land of legends to the real situations, these are the facts:</div><div class=""><br class=""></div><div class="">My Chrome browser sends this "m" line:</div><div class=""><br class=""></div><div class=""><div class="">m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99 100 101 102 121 127 120 125 107 108 109 35 36 124 119 123 118 114 115 116</div><div class=""><br class=""></div><div class="">From the offered video codecs, these are the specifications for the H.264 codecs:</div><div class=""><br class=""></div><div class=""><div class="">a=rtpmap:102 H264/90000</div><div class="">a=rtcp-fb:102 goog-remb</div><div class="">a=rtcp-fb:102 transport-cc</div><div class="">a=rtcp-fb:102 ccm fir</div><div class="">a=rtcp-fb:102 nack</div><div class="">a=rtcp-fb:102 nack pli</div><div class="">a=fmtp:102 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f</div><div class=""><br class=""></div><div class="">a=rtpmap:108 H264/90000</div><div class="">a=rtcp-fb:108 goog-remb</div><div class="">a=rtcp-fb:108 transport-cc</div><div class="">a=rtcp-fb:108 ccm fir</div><div class="">a=rtcp-fb:108 nack</div><div class="">a=rtcp-fb:108 nack pli</div><div class="">a=fmtp:108 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f</div><div class=""><br class=""></div><div class="">a=rtpmap:123 H264/90000</div><div class="">a=rtcp-fb:123 goog-remb</div><div class="">a=rtcp-fb:123 transport-cc</div><div class="">a=rtcp-fb:123 ccm fir</div><div class="">a=rtcp-fb:123 nack</div><div class="">a=rtcp-fb:123 nack pli</div><div class="">a=fmtp:123 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=640032</div><div class=""><br class=""></div><div class="">a=rtpmap:124 H264/90000</div><div class="">a=rtcp-fb:124 goog-remb</div><div class="">a=rtcp-fb:124 transport-cc</div><div class="">a=rtcp-fb:124 ccm fir</div><div class="">a=rtcp-fb:124 nack</div><div class="">a=rtcp-fb:124 nack pli</div><div class="">a=fmtp:124 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=4d0032</div><div class=""><br class=""></div><div class="">a=rtpmap:125 H264/90000</div><div class="">a=rtcp-fb:125 goog-remb</div><div class="">a=rtcp-fb:125 transport-cc</div><div class="">a=rtcp-fb:125 ccm fir</div><div class="">a=rtcp-fb:125 nack</div><div class="">a=rtcp-fb:125 nack pli</div><div class="">a=fmtp:125 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f</div><div class=""><br class=""></div><div class="">a=rtpmap:127 H264/90000</div><div class="">a=rtcp-fb:127 goog-remb</div><div class="">a=rtcp-fb:127 transport-cc</div><div class="">a=rtcp-fb:127 ccm fir</div><div class="">a=rtcp-fb:127 nack</div><div class="">a=rtcp-fb:127 nack pli</div><div class="">a=fmtp:127 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42001f</div><div class=""><br class=""></div></div><div class=""><div><br class=""></div><div>Depending on what I set as "profile-level-id" in my started pipeline (see "start_pipeline" below) I really can make webrtcbin generate a seemingly matching ANSWER. For instance if I set this:</div><div><br class=""></div><div><div style="background-color: rgb(255, 255, 255); font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; line-height: 21px; white-space: pre;" class=""><div class=""> rtph264pay_caps <span style="color: #7f0055;" class="">=</span> Gst.caps_from_string(<span style="color: #ba2500;" class="">"application/x-rtp, media=video, encoding-name=H264, profile-level-id=(string)<b class="">42001f</b>"</span>)</div><div class=""></div></div></div><div><br class=""></div><div>the answer is:</div><div><br class=""></div><div><div>a=rtpmap:102 H264/90000</div><div>a=rtcp-fb:102 nack pli</div><div>a=rtcp-fb:102 ccm fir</div><div>a=fmtp:102 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=<b class="">42001f</b></div><div>a=sendrecv</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">or with </div><div class=""><br class=""></div><div class=""><div><div style="background-color: rgb(255, 255, 255); line-height: 21px;" class=""><div style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre;" class=""> rtph264pay_caps <span style="color: rgb(127, 0, 85);" class="">=</span> Gst.caps_from_string(<span style="color: rgb(186, 37, 0);" class="">"application/x-rtp, media=video, encoding-name=H264, profile-level-id=(string)</span><span style="color: rgb(186, 37, 0);" class=""><b class="">42e01f</b></span><span style="color: rgb(186, 37, 0);" class="">"</span>)</div><div style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre;" class=""><br class=""></div><div class=""><div style="font-family: Verdana; white-space: normal;">the answer is:</div><div style="font-family: Verdana; white-space: normal;"><br class=""></div><div><div>a=rtpmap:125 H264/90000</div><div>a=rtcp-fb:125 nack pli</div><div>a=rtcp-fb:125 ccm fir</div><div>a=fmtp:125 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=<b class="">42e01f</b></div><div>a=sendrecv</div><div style="font-family: Verdana; white-space: normal;" class=""><br class=""></div><div style="font-family: Verdana; white-space: normal;" class="">This all looks pretty good. And if I use my camera instead of "videotestsrc" I can see the camera light going on...</div><div style="font-family: Verdana; white-space: normal;" class=""><br class=""></div><div style="font-family: Verdana; white-space: normal;" class="">I can also play with different packetization-modes --- each time the answer is matching...</div><div style="font-family: Verdana; white-space: normal;" class=""><br class=""></div><div style="font-family: Verdana; white-space: normal;" class="">But even with these positive signs, all I get on the remote side is a spinning wheel in a black window...</div><div style="font-family: Verdana; white-space: normal;" class=""><br class=""></div><div style="font-family: Verdana; white-space: normal;" class="">I can only get video if I start with the proper payload set TWICE... As described... This drives me crazy...</div><div style="font-family: Verdana; white-space: normal;" class=""><br class=""></div><div style="font-family: Verdana; white-space: normal;" class="">I really hate to give up, but all I get from here is "it works" with nonsense references to non-related sample code...:/</div><div style="font-family: Verdana; white-space: normal;" class=""><br class=""></div></div></div><div style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre;" class=""></div></div></div></div></div><div><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 17:54 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">@Nicolas Dufresne<div class=""><br class=""></div><div class="">Would you mind to clarify in which wise this is an "answering app"?</div><div class=""><br class=""></div><div class="">You said:</div><div class=""><br class=""></div><div class=""><div dir="auto" class=""><quote></div><div dir="auto" class="">An answering app, I didn't link it before cause it's demoware. See the known issue about mdns candidates though, this is a missing feature that can pause problem.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class=""><a href="https://gitlab.collabora.com/showcases/ibc-2019/multistream-server" class="">https://gitlab.collabora.com/showcases/ibc-2019/multistream-server</a><br class=""></div><div class=""></quote></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">But in fact, it is not. </div><div class=""><br class=""></div><div class="">Please clarify</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 16:11 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">> But nothing in the world makes webrtcbin answer an incoming H.264 offer only :))<div class=""><br class=""></div><div class="">To be precise: To be able to work after having answered the offer. The answer comes, the video not.<br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 16:05 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">BTW: I don't see the code you quoted doing handle an OFFER. Maybe I oversee something, but I don't see it emitting a "create-answer", which would be necessary to work.<div class=""><br class=""></div><div class="">That being said I'm missing something like:</div><div class=""><br class=""></div><div class=""><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; background-color: rgb(255, 255, 255);" class=""> </span><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; color: rgb(127, 0, 85); font-weight: bold;" class="">self</span><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; background-color: rgb(255, 255, 255);" class="">.webrtcbin.emit(</span><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; color: rgb(209, 38, 209);" class="">'create-answer'</span><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; background-color: rgb(255, 255, 255);" class="">, </span><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; color: rgb(10, 157, 255);" class="">None</span><span style="font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; white-space: pre; background-color: rgb(255, 255, 255);" class="">, promise)</span></div><div class=""><font face="Fira Code, Menlo, Monaco, Courier New, monospace, Menlo, Monaco, Courier New, monospace" class=""><span style="white-space: pre; background-color: rgb(255, 255, 255);" class=""><br class=""></span></font></div><div class=""><font face="Fira Code, Menlo, Monaco, Courier New, monospace, Menlo, Monaco, Courier New, monospace" class=""><span style="white-space: pre; background-color: rgb(255, 255, 255);" class=""><br class=""></span></font></div><div class=""><font face="Fira Code, Menlo, Monaco, Courier New, monospace, Menlo, Monaco, Courier New, monospace" class=""><span style="background-color: rgb(255, 255, 255);" class=""><span style="white-space: pre;" class="">In C ofc</span><br class=""></span></font><div class=""><br class=""></div><div class="">But I might be stupid (admitted)</div><div class=""><br class=""></div><div class="">Those samples doing "create-offer", "set-remote-description" bla bla... Well those work...</div><div class=""><br class=""></div><div class="">But nothing in the world makes webrtcbin answer an incoming H.264 offer only :))</div><div class=""><br class=""><div class=""><br class=""></div><div class=""><div style="background-color: rgb(255, 255, 255); font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; line-height: 21px; white-space: pre;" class=""><div class=""><br class=""></div></div><div style="background-color: rgb(255, 255, 255); font-family: "Fira Code", Menlo, Monaco, "Courier New", monospace, Menlo, Monaco, "Courier New", monospace; line-height: 21px; white-space: pre;" class=""><br class=""></div><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 15:33 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Would it be possible to send me the content of a successful OFFER you are receiving from the outside to be processed by your app?<div class=""><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 15:15 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Could you show me an offer which is successfully handled by this app?<div class=""><br class=""></div><div class=""><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 14:59 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Thanks for sharing. Will check it out. I'm aware of the MDNS candidates thing, but <div class=""><br class=""></div><div class="">a) I'm caring about those</div><div class="">b) My Chrome is disabled to send them</div><div class=""><br class=""></div><div class="">It is definitely not an ICE issue, I have<br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 14:57 schrieb Nicolas Dufresne <<a href="mailto:nicolas@ndufresne.ca" class="">nicolas@ndufresne.ca</a>>:</div><br class="Apple-interchange-newline"><div class=""><div dir="auto" class=""><div class=""><br class=""><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le dim. 22 août 2021 08 h 48, Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" class="">foreverneilyoung@googlemail.com</a>> a écrit :<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word;line-break:after-white-space" class="">BTW: I will also be happy to hand out a POC app to everybody willing to help. You would only need to have a webrtcbin capable installation of GST and Python3. Works out of the box, no strings attached.<br class=""></div></blockquote></div></div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">An answering app, I didn't link it before cause it's demoware. See the known issue about mdns candidates though, this is a missing feature that can pause problem.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class=""><a href="https://gitlab.collabora.com/showcases/ibc-2019/multistream-server" class="">https://gitlab.collabora.com/showcases/ibc-2019/multistream-server</a><br class=""></div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">In general, specially at this time of the year, a lot of folks are on vacation, leaving other really busy. Expecting someone to look into your issues for free in such a short timeframe is not realistic.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class=""><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word;line-break:after-white-space" class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 14:46 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" target="_blank" rel="noreferrer" class="">foreverneilyoung@googlemail.com</a>>:</div><br class=""><div class=""><div style="word-wrap:break-word;line-break:after-white-space" class="">Well, I have published everything I did so far. I confirm, it works if webrtc/python is the offerer and it also works as described with an incoming offer, if the pipleline is using vp8 instead of H.264.<div class=""><br class=""></div><div class="">But it does not no work with H.264. And unless anybody points me to the obvious mistake I have made with my handling there is nothing to be taken back with my conclusion.</div><div class=""><br class=""></div><div class="">Prove me wrong, if you can. It doesn't help just to say "it works". There are very rare sample of answering apps with webrtcbin. And I'm doing nothing else then those.</div><div class=""> </div><div class=""><br class=""></div><div class=""><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 22.08.2021 um 14:41 schrieb Nicolas Dufresne <<a href="mailto:nicolas@ndufresne.ca" target="_blank" rel="noreferrer" class="">nicolas@ndufresne.ca</a>>:</div><br class=""><div class=""><div dir="auto" class=""><div class=""><br class=""><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le dim. 22 août 2021 07 h 45, Neil Young via gstreamer-devel <<a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank" rel="noreferrer" class="">gstreamer-devel@lists.freedesktop.org</a>> a écrit :<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word;line-break:after-white-space" class="">Finally giving up on this. Python, webrtcbin and H.264 offer - this does not work</div><div style="word-wrap:break-word;line-break:after-white-space" dir="auto" class=""></div></blockquote></div></div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">Hi Neil, I'm sorry this did not work you and no one was available in your required delay to freely support you.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">This answer is simply to state that this works for others, the webrtcbin and rtpbin pipeline are known to be difficult, but not broken (except for few missing webrtc features of course).</div><div dir="auto" class=""><br class=""></div><div dir="auto" class=""><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word;line-break:after-white-space" dir="auto" class=""><br class=""><div dir="auto" class=""><br class=""></div><div dir="auto" class=""><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Am 21.08.2021 um 20:23 schrieb Neil Young <<a href="mailto:foreverneilyoung@googlemail.com" rel="noreferrer noreferrer" target="_blank" class="">foreverneilyoung@googlemail.com</a>>:</div><br class=""><div class=""><div style="word-wrap:break-word;line-break:after-white-space" class="">I'm hanging on this for a week now, and it seems so easy, but whatever I do, I can't make it work<div class=""><br class=""></div><div class="">My app is a Python GST app, running on 18.4. It supports two modes: "call" and "answer". In call mode the app immediately issues an H.264 or VP8 OFFER (depending on a setting). This works in 100 % of the cases. </div><div class=""><br class=""></div><div class="">What also works is when the app ANSWERs a VP8 offer. Just H.264 OFFERS are not working, even though the SDP answer looks good. I just don't get the video to remote.</div><div class=""><br class=""></div><div class="">My app works like so:</div><div class=""><br class=""></div><div class="">1) When the app has a connection to the signaling server it creates a webrtcbin object:</div><div class=""><br class=""></div><div class=""><div style="background-color:rgb(255,255,255);font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;line-height:21px;white-space:pre-wrap" class=""><div class=""> <span style="color:#210de5;font-weight:bold" class="">def</span> <span style="color:#1200bb" class="">build_webrtcbin</span>(<span style="color:#ab3c11;font-style:italic" class="">self</span>):</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"webrtcbin"</span>)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.set_property(<span style="color:#ba2500" class="">"bundle-policy"</span>, <span style="color:#ba2500" class="">"max-bundle"</span>)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.set_property(<span style="color:#ba2500" class="">"stun-server"</span>, <span style="color:#ba2500" class="">"<a rel="noreferrer noreferrer" class="">stun://stun.l.google.com:19302</a>"</span>)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'on-negotiation-needed'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_negotiation_needed)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'on-ice-candidate'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_ice_candidate)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'pad-added'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_pad_added)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'notify::connection-state'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_connection_state)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'notify::signaling-state'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_signaling_state)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'notify::ice-connection-state'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_ice_connection_state)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.connect(<span style="color:#d126d1" class="">'notify::ice-gathering-state'</span>, <span style="color:#7f0055;font-weight:bold" class="">self</span>.on_ice_gathering_state)</div><br class=""><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline <span style="color:#7f0055" class="">=</span> Gst.Pipeline.new()</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(<span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin)</div><div class=""><br class=""></div><div class="">Nothing special I guess.</div><br class=""></div></div><div style="background-color:rgb(255,255,255);line-height:21px" class=""><div style="font-family:Verdana;white-space:normal" class="">2) When the SDP OFFER comes in, the app does this:</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">2a) It starts the H.264 pipeline with `start_pipeline`. </div><div style="font-family:Verdana;white-space:normal" class="">2b) It emits the remote description to the local webrtcbin</div><div class=""><div style="font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;white-space:pre-wrap;line-height:21px" class=""><span style="color:#7f0055;font-weight:bold" class=""><br class=""></span></div><div style="font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;white-space:pre-wrap;line-height:21px" class=""><span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.emit(<span style="color:#d126d1" class="">'set-remote-description'</span>, desc, promise)</div><div style="font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;white-space:pre-wrap;line-height:21px" class=""><br class=""></div><div style="line-height:21px" class="">2c) It creates an answer calling `self.create_answer()`</div><div style="line-height:21px" class=""><br class=""></div><div style="line-height:21px" class=""><div style="font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;line-height:21px;white-space:pre-wrap" class=""><div class=""> <span style="color:#210de5;font-weight:bold" class="">def</span> <span style="color:#1200bb" class="">create_answer</span>(<span style="color:#ab3c11;font-style:italic" class="">self</span>):</div><div class=""> promise <span style="color:#7f0055" class="">=</span> Gst.Promise.new_with_change_func(<span style="color:#7f0055;font-weight:bold" class="">self</span>.on_answer_created, <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin, <span style="color:#0a9dff" class="">None</span>)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.emit(<span style="color:#d126d1" class="">'create-answer'</span>, <span style="color:#0a9dff" class="">None</span>, promise)</div><div style="line-height:21px" class=""><div class=""> </div><div class=""><span style="color:#210de5;font-weight:bold" class=""> def</span> <span style="color:#1200bb" class="">on_answer_created</span>(<span style="color:#ab3c11;font-style:italic" class="">self</span>, <span style="color:#ab3c11;font-style:italic" class="">promise</span>, <span style="color:#ab3c11;font-style:italic" class="">_</span>, <span style="color:#ab3c11;font-style:italic" class="">__</span>):</div><div class=""> <span style="color:#d126d1" class="">''' Local WebRTC stack has created an answer '''</span></div><div class=""> promise.wait()</div><div class=""> reply <span style="color:#7f0055" class="">=</span> promise.get_reply()</div><div class=""> answer <span style="color:#7f0055" class="">=</span> reply.get_value(<span style="color:#d126d1" class="">'answer'</span>)</div><div class=""> promise <span style="color:rgb(127,0,85)" class="">=</span> Gst.Promise.new()</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin.emit(<span style="color:#d126d1" class="">'set-local-description'</span>, answer, promise)</div><div class=""> promise.interrupt()</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.send_sdp_answer(answer) # Forwarding the answer to remote using the signaling server</div></div></div></div><div style="font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;white-space:pre-wrap;line-height:21px" class=""><br class=""></div></div><div style="font-family:Verdana;white-space:normal" class="">Observations so far:</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">- It doesn't work if I don't set a payload-type which matches a payload type carried by the OFFERER or if I omit the payload-type. With ALL browsers it is sufficient to use the payload-type carried by the first H.264 element in the OFFER</div><div style="font-family:Verdana;white-space:normal" class="">- It is not necessary to set the `profile-level-id`</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">The best result I can achieve with this flow is a spinning wheel in the browser. No video.</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">BUT: </div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">When I issue a call to `start_pipeline` somewhere shortly after the start (I use the moment, when I have a connection with the signaling server for this) with _exactly_the_same_payload_type_that_will_match_later_, I 100% have a video...</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">This MUST be a side effect, because the log complains about the second `start_pipeline` (warnings, it seems to ignore it).... But it works. Of course this is not a working solution, because</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">a) I would have to know the payload-type beforehand (it doesn't work if I use another payload-type in the first start)</div><div style="font-family:Verdana;white-space:normal" class="">b) I would have to parse the incoming SDP for the first H.264 (which is doable)</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class="">What am I doing wrong?</div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class=""><br class=""></div><div style="font-family:Verdana;white-space:normal" class=""><div style="font-family:"Fira Code",Menlo,Monaco,"Courier New",monospace,Menlo,Monaco,"Courier New",monospace;line-height:21px;white-space:pre-wrap" class=""><div class=""> <span style="color:#210de5;font-weight:bold" class="">def</span> <span style="color:#1200bb" class="">start_pipeline</span>(<span style="color:#ab3c11;font-style:italic" class="">self</span>, <span style="color:#ab3c11;font-style:italic" class="">payload_type</span>):</div><div class=""> videotestsrc <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"videotestsrc"</span>, <span style="color:#ba2500" class="">"videotestsrc"</span>)</div><div class=""> videotestsrc.set_property(<span style="color:#ba2500" class="">"is-live"</span>, <span style="color:#0a9dff" class="">True</span>)</div><div class=""> videotestsrc.set_property(<span style="color:#ba2500" class="">"pattern"</span>, <span style="color:#ba2500" class="">"smpte"</span>)</div><br class=""><div class=""> videotestsrc_caps <span style="color:#7f0055" class="">=</span> Gst.caps_from_string(<span style="color:#ba2500" class="">"video/x-raw, width=1280, height=720"</span>)</div><div class=""> </div><div class=""> videotestsrc_caps_filter <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"capsfilter"</span>)</div><div class=""> videotestsrc_caps_filter.set_property(<span style="color:#ba2500" class="">"caps"</span>, videotestsrc_caps)</div><br class=""><div class=""> videoconvert <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"videoconvert"</span>, <span style="color:#ba2500" class="">"videoconvert"</span>)</div><br class=""><div class=""> x264enc <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"x264enc"</span>, <span style="color:#ba2500" class="">"x264enc"</span>)</div><div class=""> x264enc.set_property(<span style="color:#ba2500" class="">"threads"</span>, <span style="color:#ff8000" class="">4</span>)</div><div class=""> </div><div class=""> x264enc_caps <span style="color:#7f0055" class="">=</span> Gst.caps_from_string(<span style="color:#ba2500" class="">"video/x-h264, profile=constrained-baseline"</span>)</div><br class=""><div class=""> x264enc_caps_filter <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"capsfilter"</span>)</div><div class=""> x264enc_caps_filter.set_property(<span style="color:#ba2500" class="">"caps"</span>, x264enc_caps)</div><br class=""><div class=""> rtph264pay <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"rtph264pay"</span>, <span style="color:#ba2500" class="">"rtph264pay"</span>)</div><div class=""> rtph264pay.set_property(<span style="color:#ba2500" class="">"config-interval"</span>, <span style="color:#098eff;font-weight:bold" class="">-</span><span style="color:#ff8000" class="">1</span>)</div><div class=""> rtph264pay.set_property(<span style="color:#ba2500" class="">"aggregate-mode"</span>, <span style="color:#ba2500" class="">"zero-latency"</span>)</div><br class=""><div class=""> rtph264pay_caps <span style="color:#7f0055" class="">=</span> Gst.caps_from_string(<span style="color:#ba2500" class="">"application/x-rtp, media=video, encoding-name=H264"</span>)</div><div class=""> rtph264pay_caps.set_value(<span style="color:#ba2500" class="">"payload"</span>, payload_type)</div><br class=""><div class=""> rtph264pay_caps_filter <span style="color:#7f0055" class="">=</span> Gst.ElementFactory.make(<span style="color:#ba2500" class="">"capsfilter"</span>)</div><div class=""> rtph264pay_caps_filter.set_property(<span style="color:#ba2500" class="">"caps"</span>, rtph264pay_caps)</div><br class=""><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(videotestsrc)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(videotestsrc_caps_filter)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(videoconvert)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(x264enc)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(x264enc_caps_filter)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(rtph264pay)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.add(rtph264pay_caps_filter)</div><br class=""><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(videotestsrc, videotestsrc_caps_filter)</div><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(videotestsrc_caps_filter, videoconvert)</div><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(videoconvert, x264enc)</div><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(x264enc, x264enc_caps_filter)</div><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(x264enc_caps_filter, rtph264pay)</div><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(rtph264pay, rtph264pay_caps_filter)</div><div class=""> <a href="http://gst.element.link/" rel="noreferrer noreferrer" target="_blank" class="">Gst.Element.link</a>(rtph264pay_caps_filter, <span style="color:#7f0055;font-weight:bold" class="">self</span>.webrtcbin)</div><div class=""> <span style="color:#7f0055;font-weight:bold" class="">self</span>.pipeline.set_state(Gst.State.PLAYING)</div><br class=""></div></div></div></div></div></blockquote></div><br class=""></div></div></blockquote></div></div></div> </div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></div></blockquote></div></div></div> </div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></div></div></div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></div></div></body></html>