Video streaming servers architecture

I'm looking for someone or company who could give us the best solution for video streaming online on one of our clients website (while saving costs): Requirments are like this: - For now there is 4 servers for video streaming - video streaming is done by HSL through nimble - Servers bandwith are limited for sure, so here's the main challenge. Should we use CDN or should we upload the same video to all servers and then upon user request to check server bandwish usage and to the give the right link for the relevant server. Or do it by caching between servers? - The solution should be flexible and dynamic where we can add any amount of servers at anytime and disconnect any at anytime as well