I’m trying to figure out the best way to have one browser client broadcast to many viewers through janus using only a single stream from the broadcaster. I’ve looked through the demos but I’m unclear on whether the VideoRoom plugin operates this way or not. The streaming plugin does, but I want my input to come from another client. it seems like this should be possible by somehow mashing both plugins together, but I can’t get a grip on what that would look like… maybe a new ‘rebroadcasting’ client that joins 2 different rooms and just rebroadcasts from one to the other? Any guidance would be appreciated.
I should clarify, by “best way”, I mean the one I can slap together in 2 days, to serve only a handful of viewers. 
VideoRoom does the producer → many consumers. I think streaming is more for taking an already produced stream. So videoroom if I understand your use case.
Depends on how many viewers. You may want to check this blog post which provides some more info on both, for a use case similar to yours:
It also links to other material I shared over the years for scalability.
TL;DR, at the moment the Streaming plugin is more optimized for broadcasting if you want a larger audience, but it needs media to be fed to it, e.g., via VideoRoom RTP forwarders. Using the VideoRoom alone is possible, but you’ll need something like the “helper threads” PR linked there.