video.js HLS Tech

A video.js tech that plays HLS video on platforms that don't support it but have Flash.

Getting Started

Download the Media Source plugin as well as the HLS tech. On your web page:

<script src="video.js"></script>
<script src="videojs-media-sources.js"></script>
<script src="videojs-hls.min.js"></script>
<script>
  var player = videojs('test-vid');
  player.play();
</script>

Documentation

HTTP Live Streaming (HLS) has become a de-facto standard for streaming video on mobile devices thanks to its native support on iOS and Android. There are a number of reasons independent of platform to recommend the format, though:

• Supports (client-driven) adaptive bitrate selection
• Delivered over standard HTTP ports
• Simple, text-based manifest format
• No proprietary streaming servers required

Unfortunately, all the major desktop browsers except for Safari are missing HLS support. That leaves web developers in the unfortunate position of having to maintain alternate renditions of the same video and potentially having to forego HTML-based video entirely to provide the best desktop viewing experience.

This tech attempts to address that situation by providing a polyfill for HLS on browsers that have Flash support. You can deploy a single HLS stream, code against the regular HTML5 video APIs, and create a fast, high-quality video experience across all the big web device categories.

Check out the full documentation for details on how HLS works and advanced configuration. A description of the adaptive switching behavior is available, too.

The videojs-hls tech is still working towards a 1.0 release so it may not fit your requirements today. Specifically, there is no support for:

• Alternate audio and video tracks
• Subtitles
• Segment codecs other than H.264 with AAC audio
• Internet Explorer < 10

Options

You may pass in an options object to the hls tech at player initialization. You can pass in options just like you would for any other tech:

videojs(video, {
  hls: {
    withCredentials: true
  }
});

withCredentials

Type: boolean

When the withCredentials property is set to true, all XHR requests for manifests and segments would have withCredentials set to true as well. This enables storing and passing cookies from the server that the manifests and segments live on. This has some implications on CORS because when set, the Access-Control-Allow-Origin header cannot be set to *, also, the response headers require the addition of Access-Control-Allow-Credentials header which is set to true. See html5rocks's article for more info.

Runtime Properties

player.hls.playlists.master

Type: object

An object representing the parsed master playlist. If a media playlist is loaded directly, a master playlist with only one entry will be created.

player.hls.playlists.media

Type: function

A function that can be used to retrieve or modify the currently active media playlist. The active media playlist is referred to when additional video data needs to be downloaded. Calling this function with no arguments returns the parsed playlist object for the active media playlist. Calling this function with a playlist object from the master playlist or a URI string as specified in the master playlist will kick off an asynchronous load of the specified media playlist. Once it has been retreived, it will become the active media playlist.

player.hls.mediaIndex

Type: number

The index of the next video segment to be downloaded from player.hls.media.

player.hls.segmentXhrTime

Type: number

The number of milliseconds it took to download the last media segment. This value is updated after each segment download completes.

player.hls.bandwidth

Type: number

The number of bits downloaded per second in the last segment download. This value is used by the default implementation of selectPlaylist to select an appropriate bitrate to play.

Before the first video segment has been downloaded, it's hard to estimate bandwidth accurately. The HLS tech uses a heuristic based on the playlist download times to do this estimation by default. If you have a more accurate source of bandwidth information, you can override this value as soon as the HLS tech has loaded to provide an initial bandwidth estimate.

player.hls.bytesReceived

Type: number

The total number of content bytes downloaded by the HLS tech.

player.hls.selectPlaylist

Type: function

A function that returns the media playlist object to use to download the next segment. It is invoked by the tech immediately before a new segment is downloaded. You can override this function to provide your adaptive streaming logic. You must, however, be sure to return a valid media playlist object that is present in player.hls.master.

Events

loadedmetadata

Fired after the first media playlist is downloaded for a stream.

loadedplaylist

Fired immediately after a new master or media playlist has been downloaded. By default, the tech only downloads playlists as they are needed.

mediachange

Fired when a new playlist becomes the active media playlist. Note that the actual rendering quality change does not occur simultaneously with this event; a new segment must be requested and the existing buffer depleted first.

In-Band Metadata

The HLS tech supports timed metadata embedded as ID3 tags. When a stream is encountered with embedded metadata, an in-band metadata text track will automatically be created and populated with cues as they are encountered in the stream. UTF-8 encoded TXXX and WXXX ID3 frames are mapped to cue points and their values set as the cue text. Cues are created for all other frame types and the data is attached to the generated cue:

cue.frame.data

There are lots of guides and references to using text tracks around the web.

Testing

For testing, you can either run npm test or use grunt directly. If you use npm test, it will only run the karma tests using chrome. You can specify which browsers you want the tests to run via grunt's test task. You can use either grunt-style arguments or comma separated arguments:

grunt test:chrome:firefox	# grunt-style
grunt test:chrome,firefox	# comma-separated

Possible options are:

• chromecanary
• phantomjs
• opera
• chrome
• safari
• firefox
• ie

Hosting Considerations

Unlike a native HLS implementation, the HLS tech has to comply with the browser's security policies. That means that all the files that make up the stream must be served from the same domain as the page hosting the video player or from a server that has appropriate CORS headers configured. Easy instructions are available for popular webservers and most CDNs should have no trouble turning CORS on for your account.

Release History

Check out the changelog for a summary of each release.