preferredStartupQuality.js

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 *
 * This is free and unencumbered software released into the public domain.
 *
 * Anyone is free to copy, modify, publish, use, compile, sell, or
 * distribute this software, either in source code form or as a compiled
 * binary, for any purpose, commercial or non-commercial, and by any
 * means.
 *
 * In jurisdictions that recognize copyright laws, the author or authors
 * of this software dedicate any and all copyright interest in the
 * software to the public domain. We make this dedication for the benefit
 * of the public at large and to the detriment of our heirs and
 * successors. We intend this dedication to be an overt act of
 * relinquishment in perpetuity of all present and future rights to this
 * software under copyright law.
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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const bitmovin = window.bitmovin;
var PreferredStartupQuality = function (preferredStartupQualityBps, startupPhaseSeconds, conf) {
    var player;
    var availableQualities = null;
    var isInStartup = true;
    var startupTimerID;

    var preferredQuality = preferredStartupQualityBps || 1000000;
    var startupSeconds = startupPhaseSeconds || 10;

    var onVideoAdaptation = function (e) {
        if (isInStartup) {
            if (!availableQualities) {
                availableQualities = player.getAvailableVideoQualities();
                startupTimerID = setTimeout(function () {
                    isInStartup = false;
                }, startupSeconds * 1000);
            }

            for (var i = availableQualities.length - 1; i >= 0; i--) {
                if (availableQualities[i].id === e.suggested) {
                    // Use the suggested quality if it's higher than the preferred
                    return e.suggested;
                }
                if (availableQualities[i].bitrate <= preferredQuality) {
                    return availableQualities[i].id;
                }
            }

            return availableQualities[availableQualities.length - 1].id;
        }
        return e.suggested;
    };

    var onReady = function () {
        isInStartup = true;
        clearTimeout(startupTimerID);
        availableQualities = null;
    };
    
    conf.adaptation.desktop.onVideoAdaptation = onVideoAdaptation;
    conf.adaptation.mobile.onVideoAdaptation = onVideoAdaptation;

    player = new bitmovin.player.Player(document.getElementById("player"), conf);
    player.on(bitmovin.player.PlayerEvent.SourceLoaded, onReady);

    player.load(conf.source).then(function() {
        console.log('Successfully loaded source');
    }, function () {
        console.log('Error while loading source');
    });

    this.remove = function () {
        player.off(bitmovin.player.PlayerEvent.SourceLoaded, onReady);
        clearTimeout(startupTimerID);
        isInStartup = true;
        availableQualities = null;
    };

    this.stopStartup = function () {
        isInStartup = false;
        clearTimeout(startupTimerID);
    };
};