[asteadman]

Unless you are doing live video, there is no reason to transcode real-time. Do it all upfront. You need to decide on your requirements and transcode everything to your desired format.

I'd suggest https://aws.amazon.com/elastictranscoder/details/, its quite affordable and much easier than doing it yourself, assuming it does what you need.

From the research I've done, I'd suggest MPEG-DASH for reasonable cross-ish platform adaptive streaming without requiring fancy video servers. Your requirements and platforms might be different than mine though. Research is required.