Doesn't Reddit use Mux? Reddit's video player is atrocious. I'm not sure whether it is the fault of Reddit or Mux though.
Yes, Reddit is a customer, but they use Data (our quality of service analytics tool), not Video (our suite of video streaming APIs). So...it's our fault if they don't have visibility into you having a bad time, but we aren't in a place to actually fix it quite yet :)
I'll be giving the Mux streaming API a try for my next project.