/videojs-contrib-hls

HLS library for video.js

Primary LanguageJavaScriptOtherNOASSERTION

video.js HLS Source Handler

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Play back HLS with video.js, even where it's not natively supported.

Lead Maintainer: Jon-Carlos Rivera @imbcmdth

Maintenance Status: Stable

Table of Contents generated with DocToc

Installation

NPM

To install videojs-contrib-hls with npm run

npm install --save videojs-contrib-hls

CDN

Select a version of HLS from cdnjs or jsDelivr

Releases

Download a release of videojs-contrib-hls

Manual Build

Download a copy of this git repository and then follow the steps in Building

Contributing

See CONTRIBUTING.md

Talk to us

Drop by our slack channel (#playback) on the Video.js slack.

Getting Started

Get a copy of videojs-contrib-hls and include it in your page along with video.js:

<video id=example-video width=600 height=300 class="video-js vjs-default-skin" controls>
  <source
     src="https://example.com/index.m3u8"
     type="application/x-mpegURL">
</video>
<script src="video.js"></script>
<script src="videojs-contrib-hls.min.js"></script>
<script>
var player = videojs('example-video');
player.play();
</script>

Check out our live example if you're having trouble.

Video.js 6

With Video.js 6, by default there is no flash support. Instead, flash support is provided through the videojs-flash plugin. If you are trying to use Video.js version 6 and want to include flash support, you must include videojs-flash on your page before including videojs-contrib-hls

<script src="https://unpkg.com/videojs-flash/dist/videojs-flash.js"></script>
<script src="https://unpkg.com/videojs-contrib-hls/dist/videojs-contrib-hls.js"></script>

Flash, and the videojs-flash plugin, are not required, but are recommended as a fallback option for browsers that don't have a native HLS player or support for Media Source Extensions.

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 project addresses that situation by providing a polyfill for HLS on browsers that have support for Media Source Extensions, or failing that, support Flash. 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.

videojs-contrib-hls supports a bunch of HLS features. Here are some highlights:

  • video-on-demand and live playback modes
  • backup or redundant streams
  • mid-segment quality switching
  • AES-128 segment encryption
  • CEA-608 captions are automatically translated into standard HTML5 caption text tracks
  • In-Manifest WebVTT subtitles are automatically translated into standard HTML5 subtitle tracks
  • Timed ID3 Metadata is automatically translated into HTML5 metedata text tracks
  • Highly customizable adaptive bitrate selection
  • Automatic bandwidth tracking
  • Cross-domain credentials support with CORS
  • Tight integration with video.js and a philosophy of exposing as much as possible with standard HTML APIs
  • Stream with multiple audio tracks and switching to those audio tracks (see the docs folder) for info
  • Media content in fragmented MP4s instead of the MPEG2-TS container format.

Options

How to use

Initialization

You may pass in an options object to the hls source handler at player initialization. You can pass in options just like you would for other parts of video.js:

// html5 for html hls
videojs(video, {html5: {
  hls: {
    withCredentials: true
  }
}});

// or

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

// or

var options = {hls: {
  withCredentials: true
}};

videojs(video, {flash: options, html5: options});
Source

Some options, such as withCredentials can be passed in to hls during player.src

var player = videojs('some-video-id');

player.src({
  src: 'https://d2zihajmogu5jn.cloudfront.net/bipbop-advanced/bipbop_16x9_variant.m3u8',
  type: 'application/x-mpegURL',
  withCredentials: true
});

List

withCredentials
  • Type: boolean
  • can be used as a source option
  • can be used as an initialization option

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.

useCueTags
  • Type: boolean
  • can be used as an initialization option

When the useCueTags property is set to true, a text track is created with label 'ad-cues' and kind 'metadata'. The track is then added to player.textTracks(). Changes in active cue may be tracked by following the Video.js cue points API for text tracks. For example:

let textTracks = player.textTracks();
let cuesTrack;

for (let i = 0; i < textTracks.length; i++) {
  if (textTracks[i].label === 'ad-cues') {
    cuesTrack = textTracks[i];
  }
}

cuesTrack.addEventListener('cuechange', function() {
  let activeCues = cuesTrack.activeCues;

  for (let i = 0; i < activeCues.length; i++) {
    let activeCue = activeCues[i];

    console.log('Cue runs from ' + activeCue.startTime +
                ' to ' + activeCue.endTime);
  }
});
overrideNative
  • Type: boolean
  • can be used as an initialization option

Try to use videojs-contrib-hls even on platforms that provide some level of HLS support natively. There are a number of platforms that technically play back HLS content but aren't very reliable or are missing features like CEA-608 captions support. When overrideNative is true, if the platform supports Media Source Extensions videojs-contrib-hls will take over HLS playback to provide a more consistent experience.

NOTE: If you use this option, you must also set videojs.options.html5.nativeAudioTracks and videojs.options.html5.nativeVideoTracks to false. videojs-contrib-hls relies on audio and video tracks to play streams with alternate audio and requires additional capabilities only supported by non-native tracks in video.js.

blacklistDuration
  • Type: number
  • can be used as an initialization option

When the blacklistDuration property is set to a time duration in seconds, if a playlist is blacklisted, it will be blacklisted for a period of that customized duration. This enables the blacklist duration to be configured by the user.

bandwidth
  • Type: number
  • can be used as an initialization option

When the bandwidth property is set (bits per second), it will be used in the calculation for initial playlist selection, before more bandwidth information is seen by the player.

enableLowInitialPlaylist
  • Type: boolean
  • can be used as an initialization option

When enableLowInitialPlaylist is set to true, it will be used to select the lowest bitrate playlist initially. This helps to decrease playback start time. This setting is false by default.

Runtime Properties

Runtime properties are attached to the tech object when HLS is in use. You can get a reference to the HLS source handler like this:

var hls = player.tech({ IWillNotUseThisInPlugins: true }).hls;

If you were thinking about modifying runtime properties in a video.js plugin, we'd recommend you avoid it. Your plugin won't work with videos that don't use videojs-contrib-hls and the best plugins work across all the media types that video.js supports. If you're deploying videojs-contrib-hls on your own website and want to make a couple tweaks though, go for it!

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.

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.

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.

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.

hls.bytesReceived

Type: number

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

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.

Overridding this function with your own is very powerful but is overkill for many purposes. Most of the time, you should use the much simpler function below to selectively enable or disable a playlist from the adaptive streaming logic.

hls.representations

Type: function

It is recommended to include the videojs-contrib-quality-levels plugin to your page so that videojs-contrib-hls will automatically populate the QualityLevelList exposed on the player by the plugin. You can access this list by calling player.qualityLevels(). See the videojs-contrib-quality-levels project page for more information on how to use the api.

Example, only enabling representations with a width greater than or equal to 720:

var qualityLevels = player.qualityLevels();

for (var i = 0; i < qualityLevels.length; i++) {
  var quality = qualityLevels[i];
  if (quality.width >= 720) {
    quality.enabled = true;
  } else {
    quality.enabled = false;
  }
}

If including videojs-contrib-quality-levels is not an option, you can use the representations api. To get all of the available representations, call the representations() method on player.hls. This will return a list of plain objects, each with width, height, bandwidth, and id properties, and an enabled() method.

player.hls.representations();

To see whether the representation is enabled or disabled, call its enabled() method with no arguments. To set whether it is enabled/disabled, call its enabled() method and pass in a boolean value. Calling <representation>.enabled(true) will allow the adaptive bitrate algorithm to select the representation while calling <representation>.enabled(false) will disallow any selection of that representation.

Example, only enabling representations with a width greater than or equal to 720:

player.hls.representations().forEach(function(rep) {
  if (rep.width >= 720) {
    rep.enabled(true);
  } else {
    rep.enabled(false);
  }
});

hls.xhr

Type: function

The xhr function that is used by HLS internally is exposed on the per- player hls object. While it is possible, we do not recommend replacing the function with your own implementation. Instead, the xhr provides the ability to specify a beforeRequest function that will be called with an object containing the options that will be used to create the xhr request.

Example:

player.hls.xhr.beforeRequest = function(options) {
  options.uri = options.uri.replace('example.com', 'foo.com');

  return options;
};

The global videojs.Hls also exposes an xhr property. Specifying a beforeRequest function on that will allow you to intercept the options for all requests in every player on a page. For consistency across browsers the video source should be set at runtime once the video player is ready.

Example

videojs.Hls.xhr.beforeRequest = function(options) {
  /*
   * Modifications to requests that will affect every player.
   */

  return options;
};

var player = videojs('video-player-id');
player.ready(function() {
  this.src({
    src: 'https://d2zihajmogu5jn.cloudfront.net/bipbop-advanced/bipbop_16x9_variant.m3u8',
    type: 'application/x-mpegURL',
  });
});

For information on the type of options that you can modify see the documentation at https://github.com/Raynos/xhr.

Events

Standard HTML video events are handled by video.js automatically and are triggered on the player object.

loadedmetadata

Fired after the first segment is downloaded for a playlist. This will not happen until playback if video.js's metadata setting is none

HLS Usage Events

Usage tracking events are fired when we detect a certain HLS feature, encoding setting, or API is used. These can be helpful for analytics, and to pinpoint the cause of HLS errors. For instance, if errors are being fired in tandem with a usage event indicating that the player was playing an AES encrypted stream, then we have a possible avenue to explore when debugging the error.

Note that although these usage events are listed below, they may change at any time without a major version change.

HLS usage events are triggered on the tech with the exception of the 3 hls-reload-error events, which are triggered on the player.

Presence Stats

Each of the following usage events are fired once per source if (and when) detected:

Name Description
hls-webvtt master manifest has at least one segmented WebVTT playlist
hls-aes a playlist is AES encrypted
hls-fmp4 a playlist used fMP4 segments
hls-demuxed audio and video are demuxed by default
hls-alternate-audio alternate audio available in the master manifest
hls-playlist-cue-tags a playlist used cue tags (see useCueTags(#usecuetags) for details)

Use Stats

Each of the following usage events are fired per use:

Name Description
hls-gap-skip player skipped a gap in the buffer
hls-player-access player.hls was accessed
hls-audio-change a user selected an alternate audio stream
hls-rendition-disabled a rendition was disabled
hls-rendition-enabled a rendition was enabled
hls-rendition-blacklisted a rendition was blacklisted
hls-timestamp-offset a timestamp offset was set in HLS (can identify discontinuities)
hls-unknown-waiting the player stopped for an unknown reason and we seeked to current time try to address it
hls-live-resync playback fell off the back of a live playlist and we resynced to the live point
hls-video-underflow we seeked to current time to address video underflow
hls-error-reload-initialized the reloadSourceOnError plugin was initialized
hls-error-reload the reloadSourceOnError plugin reloaded a source
hls-error-reload-canceled an error occurred too soon after the last reload, so we didn't reload again (to prevent error loops)

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.value.data

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

Segment Metadata

You can get metadata about the segments currently in the buffer by using the segment-metadata text track. You can get the metadata of the currently rendered segment by looking at the track's activeCues array. The metadata will be attached to the cue.value property and will have this structure

cue.value = {
  byteLength, // The size of the segment in bytes
  bandwidth, // The peak bitrate reported by the segment's playlist
  resolution, // The resolution reported by the segment's playlist
  codecs, // The codecs reported by the segment's playlist
  uri, // The Segment uri
  timeline, // Timeline of the segment for detecting discontinuities
  playlist, // The Playlist uri
  start, // Segment start time
  end // Segment end time
};

Example: Detect when a change in quality is rendered on screen

let tracks = player.textTracks();
let segmentMetadataTrack;

for (let i = 0; i < tracks.length; i++) {
  if (tracks[i].label === 'segment-metadata') {
    segmentMetadataTrack = tracks[i];
  }
}

let previousPlaylist;

if (segmentMetadataTrack) {
  segmentMetadataTrack.on('cuechange', function() {
    let activeCue = segmentMetadataTrack.activeCues[0];

    if (activeCue) {
      if (previousPlaylist !== activeCue.value.playlist) {
        console.log('Switched from rendition ' + previousPlaylist +
                    ' to rendition ' + activeCue.value.playlist);
      }
      previousPlaylist = activeCue.value.playlist;
    }
  });
}

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.

Known Issues

Issues that are currenty know about with workarounds. If you want to help find a solution that would be appreciated!

IE10 and Below

As of version 5.0.0, IE10 and below are no longer supported.

Fragmented MP4 Support

Edge has native support for HLS but only in the MPEG2-TS container. If you attempt to play an HLS stream with fragmented MP4 segments, Edge will stall. Fragmented MP4s are only supported on browser that have Media Source Extensions available.

Testing

For testing, you run npm run test. This will run tests using any of the browsers that karma-detect-browsers detects on your machine.

Release History

Check out the changelog for a summary of each release.

Building

To build a copy of videojs-contrib-hls run the following commands

git clone https://github.com/videojs/videojs-contrib-hls
cd videojs-contrib-hls
npm i
npm run build

videojs-contrib-hls will have created all of the files for using it in a dist folder

Development

Tools

Commands

All commands for development are listed in the package.json file and are run using

npm run <command>