I was thinking about streaming a complete meeting as a livestream on youtube.
Just catch the window of your navigator with OBS and you are Done
Right.
Galene does not do any multiplexing: when a meeting consists of multiple
streams, then all of the streams are sent to all participants.
Youtube requires a single stream, so at some point somebody needs to
decode the videos, build a mosaic view, and then recode the videos. It
cannot be the Galene server, since the server does not do any recoding
(that's what makes it cheap and fast). The best place is the browser,
which already knows how to decode WebRTC streams.
So rendering in the browser and recoding using OBS seems like a perfectly
fine solution. Another solution would be to perform the recoding in the
browser itself, but I'm not sure how easy it would be.