記住選取的 YouTube 影片畫質，不需任何額外的操作介面。
// ==UserScript==
// @name YouTube Fixed Video Quality
// @name:zh-TW YouTube固定影片畫質
// @name:zh-CN YouTube固定视频画质
// @description Remember video quality without any additional user interface.
// @description:zh-TW 記住選取的 YouTube 影片畫質，不需任何額外的操作介面。
// @description:zh-CN 记住选取的 YouTube 视频画质，不需任何额外的操作介面。
// @license MIT
// @namespace https://greasyfork.org/users/1086571
// @version 1.2
// @author IzsKon
// @match https://www.youtube.com/*
// @icon https://raw.githubusercontent.com/IzsKon/YouTube-Fixed-Video-Quality/main/icon.png
// @grant GM.getValue
// @grant GM.setValue
// ==/UserScript==
(async function() {
'use strict';
let vidQuality = await GM.getValue( 'videoQuality', 1 );
let player = null;
document.addEventListener('yt-player-updated', () => {
/* Check page type. Video url should be /watch or /live */
if ( /^\/watch|^\/live/.test(window.location.pathname) ) {
setVideoQuality();
}
});
async function setVideoQuality() {
/* Load settings panel. */
let settingsBtn = document.querySelector('.ytp-settings-button');
settingsBtn.click();
settingsBtn.click();
/* Open quality selection panel. */
let qualityBtn = document.querySelector('.ytp-menuitem-content div:not(.ytp-menuitem-toggle-checkbox)');
if (!qualityBtn) { /* Video not loaded: stream not started or other issues. */
detectVideoStart();
return;
}
qualityBtn.click();
let qualityOptions = document.querySelectorAll('.ytp-quality-menu .ytp-menuitem:not(:has(.ytp-premium-label))');
/* Close quality selection panel. */
settingsBtn.click();
settingsBtn.click();
/* Select video quality. */
let nth_option = qualityOptions.length - vidQuality;
qualityOptions[ Math.max(0, nth_option) ].click();
/* Add event listener to quality selection. */
for ( let i = 0; i < qualityOptions.length; ++i ) {
qualityOptions[i].addEventListener('click', () => {
GM.setValue( 'videoQuality', qualityOptions.length - i );
});
}
}
function detectVideoStart() {
/* Prevent infinite loop b/w detectVideoStart() & setVideoQuality() in case sth go wrong. */
if (player) return;
const observer = new MutationObserver((mutations) => {
mutations.forEach((mutation) => {
if (mutation.type != 'attributes') return;
if (mutation.attributeName != 'class') return;
/* Detect when a stream starts. */
if ( player.classList.contains('unstarted-mode') ) return;
observer.disconnect();
setVideoQuality();
});
});
player = document.getElementById('movie_player');
observer.observe(player, { attributes: true });
}
})();