webrtcsink : sample fails with "Unknown message from server: {"type":"welcome", "peerId":"836..."}

[Mathieu Duponchelle]

Good news, we should remember to add a protocol version to the hello
message at some point :)

On Mon, 2023-11-13 at 22:26 +0100, Vincent Deconinck via gstreamer-
devel wrote:
> Hi,
> Thanks for the quick response. Gosh, that was the issue indeed.
> I had searched the web for "Signalling error: Unknown message from
> server" but the gitlab issue only had it... in a png screenshot. How
> come Google did not OCR it ? ;-)
> Artifacts are purged after one week so the link to the "nightly"
> build is outdated but I had no trouble finding a more recent build,
> and it worked right of the box.
> Merci bcp Mathieu :-)
> Vincent
> 
> On Mon, Nov 13, 2023 at 4:40 PM Mathieu Duponchelle
> <mathieu at centricular.com> wrote:
> > Hey,
> > 
> > Protocol mismatch, refer to
> > https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/issues/454
> > for a duplicate :)
> > 
> > Best,
> > Mathieu
> > On Mon, 2023-11-13 at 00:53 +0100, Vincent Deconinck via gstreamer-
> > devel wrote:
> > > Hi,
> > > 
> > > Context: Gstreamer newbie here. I'm trying to use a pipeline to
> > > send
> > > an A/V stream to a browser using WebRTC. The streamer, signalling
> > > server and browser client will all be on the same private
> > > network.
> > > The following tests were performed on Windows 10.
> > > 
> > > What I've tried: I had success in building and using the basic
> > > webrtcbin sample but as I need a full fledged system (incl.
> > > signalling etc.), it seems webrtcsink is the way to go, so I'm
> > > now
> > > trying to use it.
> > > I followed the README at
> > > https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/blob/main/net/webrtc/README.md
> > > The code is built, the signalling server runs and the GstWebRTC
> > > API
> > > runs in the browser.
> > > 
> > > Problem: The command to launch the pipeline (gst-launch-1.0
> > > webrtcsink name=ws meta="meta,name=gst-stream" videotestsrc ! ws.
> > > audiotestsrc ! ws.) fails with:
> > > 
> > > ERROR: from element /GstPipeline:pipeline0/GstWebRTCSink:ws:
> > > GStreamer encountered a general stream error.
> > > Additional debug info:
> > > net\webrtc\src\webrtcsink\imp.rs(1404):
> > > gstrswebrtc::webrtcsink::imp
> > > (): /GstPipeline:pipeline0/GstWebRTCSink:ws:
> > > Signalling error: Unknown message from server:
> > > {"type":"welcome","peerId":"8365d5c1-a2c8-4a1b-a9b0-
> > > 96c0dfe12060"}
> > > 
> > > Question: Any idea what the reason could be ? What can I try to
> > > understand what is going on ?
> > > 
> > > Any help would be greatly appreciated
> > > 
> > > Vincent
> > > 
> > > PS: I was amazed at the quality of the gstreamer documentation,
> > > and
> > > in particular the tutorials. I have never seen explanations of
> > > such
> > > quality for an open-source project.
> > > Kudos to the contributors !