H.265 / MPEG DASH / VP9 is not ready for widespread deployment, one big reason being client side playback capability as the player technology sprints to keep up with the video encoding technology. The reasons being thrown out there for migrating to H265, even from H.264 multi bit rate HLS, like most new tech, is compelling:
Better compression and faster/cheaper delivery over lower bitrates. Hard to argue with that. Any content distributor seeking to distribute content to mobile devices over congested 3G/4G/LTE networks, these traits are highly desirable. Anyone hoping to streak 4K, these traits are completely necessary. It’s not as easy to migrate as some of the MPEG DASH / VP9 / H.265 advocates are claiming right now though.
The reality of real-world use of H.265 hosting and the ultra HD codecs such as VP9, can deflate any optimistic plans. In this video, from streamingmedia.com, learn if and how H.264 and H.265 compression and deployment options can be used in typical online streaming workflows, and more importantly, if your target audiences can benefit. Examples of x264 and x265 output are compared for bitrate, compression time, and file size.