HTTP Live Streaming (HLS) is an ABR streaming communications protocol, specified and implemented by Apple, that become core to the video technology on iPhone and iPad devices. Related clients were also rapidly developed for all other streaming platforms. HLS provides a highly efficient security model that's endorsed by Hollywood studios, broadcasters and other major content owners. HLS naturally supports both live and on-demand content streams, where the segments of video at the various bitrates were historically created in “chunks” of small MPEG2-TS files. The manifest file is a text file with an .m3u8 extension (based on prior MP3 streaming formats). Apple standardized the HLS format through draft IETF RFC documents [https://tools.ietf.org/html/draft-pantos-http-live-streaming-00]. HLS has evolved significantly over time and updates to the specification continue to be published by R. Pantos et al. Because of the significant base of Apple devices, HLS based content played a major role in generating momentum behind ABR streaming for all of today's major services. As a practical matter, the HLS format has been wildly popular for streaming video services and arguably still dominates the delivery world.