HTTP Live Streaming playlist files

An HTTP Live Streaming playlist file provides information for a playback device about the available content for a multimedia presentation.

Specifically, HTTP Live Streaming playlist files provide information about:

  • The media segments that comprise the multimedia presentation
  • Available content renditions that can be used in the content selection process (for example, different languages)
  • Available content variants (for example, content rendered for different bandwidths)

HTTP Live Streaming playlist files are regular M3U playlists, extended by the addition of information specific to HTTP Live Streaming. This extended information is contained in lines that start with an #EXT prefix inside the playlist. A playlist contains uniform resource identifiers (URIs) that point to media files or to other playlists.

The HTTP Live Streaming protocol defines a specific type of playlist, known as a variant playlist, to allow a client device to select from different versions of the same piece of content. For example, these versions can be encoded at different bit rates to enable the client to switch to a lower data rate (for example, when the available delivery bandwidth is reduced) or to switch to a higher data rate to improve audio and video quality. A variant playlist may also point to alternative content for a presentation, such as an alternative language version of the content.