Plus a delayed job worker process managed by upstart, tada, got yourself a video-encoding-and-streaming system.
> And most importantly, do you have to tune the linux kernel to achieve performance on this (just saw the LinkedIn NUMA post as well, so thinking about that)
Ha, no. Definitely not until you have really significant scale - it's remarkably fast on a reasonable dedicated server and scales well across cores, run N/2 to N+1 delayed_job processes for N cores depending on how well ffmpeg et al make use of your cores. Well faster than realtime.