HTTP Live Streaming (HLS) Format – The Pros, Cons and How it Works

This blog focuses on HLS, or HTTP live streaming, which is one of the most popular protocols used to stream video today. HLS format is an adaptive bitrate live streaming video protocol. Originally developed by Apple for use on iOS, Mac OS, and Apple TV devices, HLS streaming has become the most widely used live video protocol.

This article is going to take a look at the pros and cons of HTTP live streaming. We’ll compare it to a few alternative formats as well. We’ll also look at the history of the HLS format, and ask where it came from, and why.

HLS video is delivered via the HTML5 web communication protocol, the latest online standard for web content. HTML5 video players support online video delivered via a variety of protocols. These include HTTP Live Streaming (HLS) and MPEG-DASH.

You can think of the streaming protocol as the method that defines what format the video uses, how it’s compressed, the size of the chunks sent, and so on.

HLS was developed to provide an alternative to Flash video. Technically speaking, uses H.264 video compression, AAC, or MP3 for audio compression, and transmits streams using the MPEG-TS container format.

Video streaming via HLS works by chopping an MP4 video stream into short, ~10-second video chunks. Streams are described using M3U8 playlists that are created by the HTTP server. This playlist also called a manifest file, indexes the video chunks.