HLS

Apple’s adaptive bitrate (ABR) technology, known as HTTP Live Streaming, can be used for both unbounded (live) and bounded (on-demand) content playback. Apple’s HLS uses AVC/H.264 video encoding but it is the only major HTTP streaming technology to encapsulate audio and video elementary streams into a multiplexed format. HLS uses MPEG-2 Transport Stream, requiring that both audio and video be present in the transport stream prior to segmentation. While HLS is not a standards-based segmentation and delivery technology, it is currently the most popular ABR technology, in use in all iOS-based devices and a number of Android-based mobile devices. Apple maintains a series of external-facing updates to HLS, currently at version 12, in an ongoing series of documents informally called “the Pantos spec” after the name of its author.