We actually don't use FFMpeg to do the compression, we use the hardware encoders, so it uses much less CPU. That's how we're able to broadcast at a much better resolution.
It's also bandwidth adaptive streaming, backed by a global CDN, and generates both Live and VOD HLS streams.
But, more importantly, we've designed it in such a way that as a developer, you don't even have to worry about that! The library just exposes a really simple API that does all of the video magic for you.