HTTP Live Streaming (or HLS) is an adaptive streaming communications protocol created by Apple to communicate with iOS and Apple TV devices and Macs running OSX in Snow Leopard or later. HLS can distribute both live and on-demand files and is the sole technology available for adaptively streaming to Apple devices, which is an increasingly important target segment to streaming publishers.
HLS is widely supported in streaming servers from vendors like Adobe,Microsoft, RealNetworks, and Wowza, as well as real time transmuxing functions in distribution platforms like those from Akamai. The popularity of iOS devices and this distribution-related technology support has also led to increased support on the player side, most notably from Google in Android 3.0.
In the Apple App Store, if you produce an app that delivers video longer then ten minutes or greater than 5MB of data, you must use HTTP Live Streaming, and provide at least one stream at 64Kbps or lower bandwidth. Any streaming publisher targeting iOS devices via a website or app should know the basics of HLS and how it’s implemented.