Video.js quality picker

Adds quality picker menus to video.js which allows users to perform manual quality selection for multi-bitrate video, or multi-language audio / subtitles.

NOTE: In this project, quality can refer to:

• a specific video / audio bitrate (or auto selection)
• a specific audio / subtitle language (or disabled subtitles)

Installation

Plugin works with video.js 5.0 and newer.

Make a tech / source handler compatible

How it works

The plugin listens to the custom event loadedqualitydata fired by player's tech / source handler.

The tech must:

• Get the quality list from the underlying playback technology
• Format the quality list to the format given below
• Implement a callback function for the click action on the quality picker
• Trigger a custom tech event loadedqualitydata, with a payload which format is described below

Expected format

Here is expected payload structure:

{
  qualityData: {
    video: [ Quality ], // An array of Quality objects, as defined below
    audio: [ Quality ],
    subtitle: [ Quality ]
  },
  qualitySwitchCallback: Function // callback function used for quality switching, as defined below
}

NOTES:

• In the following, track type refers to the enum: "video" | "audio" | "subtitle".
• it's not mandatory to pass an array of Quality for every track type, it can be undefined. No quality picker button will be added for this track type.
• If the length of a Quality array is <= 1, no quality picker button will be added for its track type.

qualitySwitchCallback

qualitySwitchCallback(qualityId, trackType)

This callback function will be called with the Quality id and the the track type as arguments. Its role is to effectively perform the quality change on the player

Quality

Examples

{
  id: -1,
  label: 'auto',
  selected: true
}

{
  id: { adaptationSetId: 0, representationId: 2},
  label: '720p',
  selected: false
}

Properties

property	type	description
id	Any	Unique identifier for the quality. Can be an integer (level index for HLS), or an object ( {adaptationSetId: ..., representationId: ...} for Dash) .
label	String	The text that will be displayed to identify this quality in the drop down menu
selected	Boolean	Should be true for ONE quality ONLY: the one that is currently played by the player

Hls.js Example

    // hls.js init
    var hls = new Hls(config);
    hls.on(Hls.Events.MANIFEST_PARSED, onManifestParsed); // Listen to the event MANIFEST_PARSED, to get the quality list.

    hls.loadSource(url);
    hls.attachMedia(video);

    //...
    //...
    //...


    // Callback function
    function switchQuality(qualityId, trackType) {
        hls.nextLevel = qualityId; // Perform quality switch using hls.js API
    }

    function onManifestParsed(event, data) {
        // 1. Format payload
        var cleanTracklist = [];

        // Add an "auto" quality.
        if (data.levels.length > 1) {
            var autoLevel = {
                id: -1,
                label: "auto",
                selected: -1 === hls.manualLevel
            };
            cleanTracklist.push(autoLevel);
        }

        // Format each hls level into the expected "Quality" format
        data.levels.forEach(function(level, index) {
            var quality = {}; // Don't write in level (shared reference with Hls.js)
            quality.id = index;
            quality.selected = index === hls.manualLevel;
            quality.label = _levelLabel(level);

            cleanTracklist.push(quality);
        });

        var payload = {
            qualityData: {video: cleanTracklist},
            qualitySwitchCallback: switchQuality
        };

        // 2. Trigger custom event from tech
        tech.trigger('loadedqualitydata', payload);

        // Helper method used to format the Quality's label
        function _levelLabel(level) {
            if (level.height) return level.height + "p";
            else if (level.width) return Math.round(level.width * 9 / 16) + "p";
            else if (level.bitrate) return (level.bitrate / 1000) + "kbps";
            else return 0;
        }
    }