Youtube Automatic Max Quality

Set Youtube player automatically to max quality.

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(Tôi đã có Trình quản lý tập lệnh người dùng, hãy cài đặt nó!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Youtube Automatic Max Quality
// @namespace    http://tampermonkey.net/
// @version      2024-03-02
// @description  Set Youtube player automatically to max quality.
// @author       Santeri Hetekivi
// @match        *://*.youtube.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @grant        none
// @license      Apache-2.0
// ==/UserScript==

(function () {
    'use strict';
    /**
     * Get element with selector and call callback with it.
     * @param {string} selector Selector for the element.
     * @param {function} callback Callback function to call with the element.
     */
    function forElement(selector, callback) {
        // Init forElement.timeoutCount.
        if (forElement.timeoutCount === undefined) {
            forElement.timeoutCount = {}
        }
        // Init forElement.timeoutCount[selector].
        if (forElement.timeoutCount[selector] === undefined) {
            forElement.timeoutCount[selector] = 0
        }

        // Get element.
        const element = document.querySelector(selector)

        // If element not found.
        if (element === null) {
            // try again after timeout.
            setTimeout(
                function () {
                    forElement(selector, callback)
                },
                (
                    // Base timeout.
                    100
                    *
                    // Increase timeout after each try.
                    (forElement.timeoutCount[selector]++)
                )
            )
        }
        // If element found
        else {
            // reset timeout count
            forElement.timeoutCount[selector] = 0
            // and call callback with element.
            callback(element)
        }
    }

    // Init previous video id.
    let videoIdPrevious = null;

    /**
     * Run on url change.
     */
    function onUrlChange() {
        // Get video id from url.
        const videoId = (new URLSearchParams(window.location.search)).get("v");
        // If
        if (
            // did not get video id
            videoId === null
            ||
            // or video id did not change
            videoId === videoIdPrevious
        ) {
            // just return.
            return
        }

        // Update previous video id.
        videoIdPrevious = videoId;

        // Run for
        forElement(
            // video player
            ".html5-video-player",
            function (player) {
                // get max quality (cannot use getMaxPlaybackQuality because it returns 'auto')
                const maxQuality = player.getAvailableQualityLevels()[0]
                // set max quality.
                player.setPlaybackQualityRange(maxQuality, maxQuality)
            }
        )

        // NOTE: If you dont have Youtube Premium or dont care for 1080p Premium, you dont need this:
        // Run for
        forElement(
            // settings button
            ".ytp-settings-button",
            function (buttonSettings) {
                // click settings button
                buttonSettings.click()
                // and run for
                forElement(
                    // quality selection button
                    ".ytp-panel .ytp-menuitem:nth-child(5)",
                    function (buttonSelectQuality) {
                        // click quality selection button
                        buttonSelectQuality.click()
                        // and run for first quality option
                        forElement(
                            ".ytp-quality-menu .ytp-menuitem:nth-child(1)",
                            function (buttonMaxQuality) {
                                // click max quality option.
                                buttonMaxQuality.click()
                            }
                        )
                    }
                )
            }
        )
    }

    // Add event listener for
    window.addEventListener(
        // Youtube page data updated event.
        'yt-page-data-updated',
        function () {
            onUrlChange();
        }
    );

    // Run on url change once on first load.
    onUrlChange();
})();