I've spent thousands on "cloud" based transcoding services and I'm generally unhappy with the results. Even at low volumes these services are expensive, not very configurable, failures are common and diagnostic information is nowhere to be found. These serivces are simply hosting ffmpeg with some reasonable defaults, how hard can this be?
I went back found some scripts from when I ran engineering for an adult-content site. Combined those with some new tricks I learned engineering for a marketing startup. Added some Job control and a REST-style API on the top.