YouTube 720p

change default YouTube video quality to 720p or highest available below 720p. can be used for other video qualities by changing preferredQuality in the code below.
Εγκατάσταση αυτού του κώδικα Βοήθεια
Κάντε μια ερώτηση, δημοσιεύστε μια ανασκόπηση, ή αναφέρετε τον κώδικα.
Αναδίπλωση γραμμών
// ==UserScript==
// @name         YouTube 720p
// @namespace    http://www.youtube.com/
// @version      1.4.3
// @description  change default YouTube video quality to 720p or highest available below 720p. can be used for other video qualities by changing preferredQuality in the code below.
// @match        http://youtube.com/*
// @match        https://youtube.com/*
// @match        http://www.youtube.com/*
// @match        https://www.youtube.com/*
// @grant        none
// @run-at       document-end
// ==/UserScript==


youtubeOverride = function (unsafeWindow) {
    
    // qualities = ['auto', 'hd1080', 'hd720', 'large', 'medium', 'small', 'tiny'];
    // set the quality desired here:
    preferredQuality = 'hd720';
    // overrideMaxAttempts = 30;
    overrideTryDelay = 1000;
    
    console.log('override script starting');
    if (location.pathname.indexOf("/embed/") === 0) {
        var player = unsafeWindow.yt.player.getPlayerByElement(unsafeWindow.document.getElementById("player"));
        if (player != null) {
            overridePlayer(player);
        } else {
            console.log('cannot get player api');
        }
    } else {
        tryToOverride();
        
        var target = document.getElementById('player');
        var MutationObserver = window.MutationObserver;
        var observer = new MutationObserver(function (mutations) {
            mutations.forEach(function (mutation) {
                if (mutation.target.id === 'player-unavailable')  {
                    console.log('player mutation detected');
                    var player = unsafeWindow.document.getElementById('movie_player');
                    if (player != null) {
                        overridePlayer(player);
                    } else {
                        console.log('cannot get player api2');
                    }
                }
            });
        });
        observer.observe(target, { childList: true, subtree: true });
    }
    
    function getPlayerApi() {
        if (location.pathname.indexOf("/embed/") === 0) {
            var player = unsafeWindow.yt.player.getPlayerByElement(unsafeWindow.document.getElementById("player"));
            return player;
        } else {
        	return unsafeWindow.document.getElementById('movie_player');
        }
    }
        
    function tryToOverride(player) {
        console.log('quality override starting');

        player = player != null ? player : getPlayerApi();

        if (player == null || !('setPlaybackQuality' in player)) {
            console.log('error: setPlaybackQuality not available');
            return false;
        }

        var qualityLevels = player.getAvailableQualityLevels();
        var qualityToSet = null;
        for (var i = 0; i < qualityLevels.length; i++) {
            if (qualityLevels[i].trim().toLowerCase() === preferredQuality) {
                qualityToSet = qualityLevels[i];
                break;
            }
        }
        if (qualityToSet == null) {
            qualityToSet = qualityLevels[0];
        }
        if (qualityToSet == null) {
            console.log('error: no quality levels available');
            return false;
        }
        player.setPlaybackQuality(qualityToSet);
        console.log('set quality to ' + qualityToSet);
        return qualityToSet == player.getPlaybackQuality();
    }
    
    function overridePlayer(player) {
        if (overridePlayer.running) {
            return;
        }
        overridePlayer.running = true;
        
        overrideTimeoutFunc.attempts = 0;
        overrideTimeoutFunc();
        
        function overrideTimeoutFunc() {
            overrideTimeoutFunc.attempts++;
            var success = tryToOverride(player);
            if (!success /*&& overrideTimeoutFunc.attempts < overrideMaxAttempts*/) {
                setTimeout(overrideTimeoutFunc, overrideTryDelay)
            } else {
                overridePlayer.running = false;
            }
        }
    }
};

(function () {
    // inject script into page
    if (this.unsafeWindow != null) {
        youtubeOverride(unsafeWindow);
    } else {
        var scriptElem = document.createElement('script');
        scriptElem.setAttribute('type', 'text/javascript');
        scriptElem.text = '(' + youtubeOverride.toString() + ')(window);';
        
        document.documentElement.appendChild(scriptElem);
        document.documentElement.removeChild(scriptElem);
    }
})();