Use HEVC (a.k.a. "MPEG-H Part-2") over MPEG-4 to save 25-50% the space for the same quality.

One of the best codecs is the HEVC a.k.a. H.265 a.k.a. MPEG-H Part-2, the successor to MPEG-4 Part 10. It offers 25-50% better compression/less space used with the same quality as MPEG-4. But features and selling points aside, I need some technical know-how. I want to know how they work so that I can pull them to my site or server (usually from YT or something), or make them available from a server. In nearly every case the video’ll be distributed over HTTP. I could learn the tools to do so, and hopefully the tools’ll be in Clojure.