I tried restream.io (didn't knew that!) to check if stream can be arrived there and restreamed to Twitch, all worked fine!
We use a Datavideo Encoder, the settings are:
Resolution : 1280 x 720
Framerate : 50.00 (Progressive)
Scale Down NO
SD Aspect Ratio (Input) 16:9
H.264 Encode Main 3.1
GOP Structure IPPP
GOP Size 50
Video Bitrate (Kbps) 2500
Video Rate Mode CBR
Audio Stereo Stereo
Stereo Bitrate (Kbps) 384
Audio Source DIG
Analog Audio System EBU
I think I'm going to create an issue on their Github.
However, Peertube livestream has for us some limitations like, they don't have and will get a 'passthrough' (like a build-in restream) which many platform of course do have.
@marcusquinn generally yes, you could stream a webinar in such a way (have done this in the past with youtube). The thing you have to be aware of is that there is a delay involved (incoming buffer on the platform and then another buffer at the client). So it's not really suited if you want to react on realtime feedback/questions.