Thanks! So I have been playing with it on a RPi3. There are instructions here on how to build for the RPi: https://blog.hypriot.com/post/building-a-64bit-docker-os-for...

It has about enough CPU to handle recording about 2 streams at the same time. I think part of the problem is that Raspbian does not have the GCC flags optimized for the processor in the RPi3 and doesn't have 64bit enabled. I played a little with this image: https://blog.hypriot.com/post/building-a-64bit-docker-os-for... and it seemed to help a bit, but I didn't see huge gains.

People are using it with the ODroid, and I think they are able to do about 4 simultaneous recordings at the same time.