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m3u8 provides easy generation and parsing of m3u8 playlists defined in the HTTP Live Streaming (HLS) Internet Draft published by Apple.

  • The library completely implements version 20 of the HLS Internet Draft.
  • Provides parsing of an m3u8 playlist into an object model from any File, StringIO, or string.
  • Provides ability to write playlist to a File or StringIO or expose as string via to_s.
  • Distinction between a master and media playlist is handled automatically (single Playlist class).
  • Optionally, the library can automatically generate the audio/video codecs string used in the CODEC attribute based on specified H.264, AAC, or MP3 options (such as Profile/Level).


Add this line to your application's Gemfile:

gem 'm3u8'

And then execute:

$ bundle

Or install it yourself as:

$ gem install m3u8

Usage (creating playlists)

Create a master playlist and add child playlists for adaptive bitrate streaming:

require 'm3u8'
playlist =

Create a new playlist item with options:

options = { width: 1920, height: 1080, profile: 'high', level: 4.1,
            audio_codec: 'aac-lc', bandwidth: 540, uri: 'test.url' }
item =
playlist.items << item

Add alternate audio, camera angles, closed captions and subtitles by creating MediaItem instances and adding them to the Playlist:

hash = { type: 'AUDIO', group_id: 'audio-lo', language: 'fre',
         assoc_language: 'spoken', name: 'Francais', autoselect: true,
         default: false, forced: true, uri: 'frelo/prog_index.m3u8' }
item =
playlist.items << item

Create a standard playlist and add MPEG-TS segments via SegmentItem. You can also specify options for this type of playlist, however these options are ignored if playlist becomes a master playlist (anything but segments added):

options = { version: 1, cache: false, target: 12, sequence: 1 }
playlist =

item = 11, segment: 'test.ts')
playlist.items << item

You can pass an IO object to the write method:

require 'tempfile'
file ='test')

You can also access the playlist as a string:


M3u8::Writer is the class that handles generating the playlist output.

Alternatively you can set codecs rather than having it generated automatically:

options = { width: 1920, height: 1080, codecs: 'avc1.66.30,mp4a.40.2',
            bandwidth: 540, uri: 'test.url' }
item =

Usage (parsing playlists)

file = 'spec/fixtures/master.m3u8'
playlist =
# => true

Access items in playlist:

#  => #<M3u8::PlaylistItem:0x007fa569bc7698 @program_id="1", @resolution="1920x1080", 
#  @codecs="avc1.640028,mp4a.40.2", @bandwidth="5042000", 
#  @playlist="hls/1080-7mbps/1080-7mbps.m3u8">

Create a new playlist item with options:

options = { width: 1920, height: 1080, profile: 'high', level: 4.1,
            audio_codec: 'aac-lc', bandwidth: 540, uri: 'test.url' }
item =
#add it to the top of the playlist

M3u8::Reader is the class handles parsing if you want more control over the process.

Usage (misc)

Generate the codec string based on audio and video codec options without dealing a playlist instance:

options = { profile: 'baseline', level: 3.0, audio_codec: 'aac-lc' }
codecs = M3u8::Playlist.codecs(options)
# => "avc1.66.30,mp4a.40.2"
  • Values for audio_codec (codec name): aac-lc, he-aac, mp3
  • Values for profile (H.264 Profile): baseline, main, high.
  • Values for level (H.264 Level): 3.0, 3.1, 4.0, 4.1.

Not all Levels and Profiles can be combined and validation is not currently implemented, consult H.264 documentation for further details.


  • Implement validation of all tags, attributes, and values per HLS I-D.
  • Perhaps support for different versions of HLS I-D, defaulting to latest.


  1. Fork it ( )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Run the specs, make sure they pass and that new features are covered. Code coverage should be 100%.
  4. Commit your changes (git commit -am 'Add some feature')
  5. Push to the branch (git push origin my-new-feature)
  6. Create a new Pull Request


MIT License - See LICENSE.txt for details.