YouTube 播放时固定分辨率为 1440p 60hz，CPU 占用率过高时自动更换编码（如H.264, H.265, H.266），若画质降低明显则取消切换。
// ==UserScript==
// @name YouTube 固定分辨率 + 编码智能选择
// @namespace https://gf.qytechs.cn/users/1171320
// @version 1.04
// @description YouTube 播放时固定分辨率为 1440p 60hz，CPU 占用率过高时自动更换编码（如H.264, H.265, H.266），若画质降低明显则取消切换。
// @author yzcjd
// @author2 Lama AI 辅助
// @match *://www.youtube.com/watch?v=*
// @grant none
// @license MIT
// ==/UserScript==
(function() {
'use strict';
let cpuUsageHistory = [];
let highCpuCount = 0;
let lastChangeTime = 0;
const cpuCheckInterval = 1500;
const cpuThreshold = 50;
const changeInterval = 5000; // 切换间隔设置为 5 秒
const highCpuDuration = 3;
let videoPlayer = null;
let currentCodec = null;
let preferredCodec = null;
const preferredResolution = '1440p60';
const codecOptions = ['avc1', 'hevc', 'vvc1', 'vp9']; // 编码优先级 H.264(avc1) > H.265(hevc) > H.266(vvc1) > vp9
let observer;
const resolutionChangeThreshold = 0.7; // 允许降低的最低分辨率比率
const minHeight = 1080
// MutationObserver 监听器，用于检测视频元素
const initObserver = () => {
observer = new MutationObserver(mutations => {
for (const mutation of mutations) {
if (mutation.addedNodes) {
for (const node of mutation.addedNodes) {
if (node.tagName === 'VIDEO') {
videoPlayer = node;
setResolution();
startCpuMonitor();
return;
}
}
}
}
});
observer.observe(document.body, {
childList: true,
subtree: true
});
};
initObserver();
// 设置分辨率
function setResolution(retryCount = 0) {
if (!videoPlayer) return;
const qualityMenuBtn = document.querySelector('button.ytp-button.ytp-settings-button');
if(qualityMenuBtn){
qualityMenuBtn.click();
setTimeout(() => {
const qualityOption = Array.from(document.querySelectorAll('div.ytp-menu div.ytp-menu div.ytp-menu-label')).find(el => el.textContent.trim() === preferredResolution);
if(qualityOption) {
qualityOption.click();
} else {
const autoOption = Array.from(document.querySelectorAll('div.ytp-menu div.ytp-menu div.ytp-menu-label')).find(el => el.textContent.trim() === '自动');
if(autoOption) {
autoOption.click();
}
}
}, 500);
} else {
if (retryCount < 3) {
setTimeout(() => setResolution(retryCount + 1), 1000);
} else {
console.warn('Failed to set resolution after multiple retries');
}
}
}
function startCpuMonitor(){
if (!videoPlayer) return;
checkInitialCodec()
setInterval(checkCpu, cpuCheckInterval);
}
// 检测初始视频编码
function checkInitialCodec() {
if (!videoPlayer) return;
const playerConfig = unsafeWindow.ytplayer?.config;
if(playerConfig?.args?.player_response) {
const codecs = playerConfig.args.player_response.streamingData?.adaptiveFormats.map(format => format.mimeType.match(/codecs="([^"]+)"/)?.[1]).filter(Boolean) || [];
currentCodec = codecs.find(codec => codecOptions.includes(codec)) || null;
preferredCodec = currentCodec;
}
}
function checkCpu() {
getCpuUsage()
.then(usage => {
cpuUsageHistory.push(usage);
if (cpuUsageHistory.length > 10) {
cpuUsageHistory.shift();
}
if(usage > cpuThreshold){
highCpuCount++;
}else{
highCpuCount = 0;
}
if (highCpuCount >= (highCpuDuration*1000/cpuCheckInterval) && (Date.now() - lastChangeTime) > changeInterval) {
console.log('CPU占用率过高，更换编码');
changeVideoCodec();
lastChangeTime = Date.now();
highCpuCount = 0;
}
});
}
async function getCpuUsage() {
if (performance && performance.memory) {
return 100 * (performance.memory.usedJSHeapSize / performance.memory.jsHeapSizeLimit);
}else if(navigator.deviceMemory){
return 100 - (navigator.deviceMemory /8) * 100;
}
else {
return Promise.resolve(0);
}
}
// 切换视频编码
function changeVideoCodec() {
if (!videoPlayer) return;
const playerConfig = unsafeWindow.ytplayer?.config;
if(playerConfig?.args?.player_response){
const availableCodecs = playerConfig.args.player_response.streamingData?.adaptiveFormats.map(format => format.mimeType.match(/codecs="([^"]+)"/)?.[1]).filter(Boolean).filter(codec => codecOptions.includes(codec)) || []
const currentCodecIndex = availableCodecs.indexOf(currentCodec)
let nextCodec = null;
for(let i = 1; i < availableCodecs.length; i++){
const nextIndex = (currentCodecIndex + i) % availableCodecs.length;
if(availableCodecs[nextIndex]) {
nextCodec = availableCodecs[nextIndex];
break;
}
}
if(nextCodec) {
const currentResolution = {width: videoPlayer.videoWidth, height: videoPlayer.videoHeight}
if(currentResolution.height < minHeight){
console.warn(`当前分辨率为${currentResolution.height}, 低于1080P, 不进行编码切换`);
return;
}
currentCodec = nextCodec;
videoPlayer.pause();
console.log(`切换到 ${currentCodec} 编码`)
videoPlayer.play();
videoPlayer.src = playerConfig.args.url
videoPlayer.addEventListener('loadedmetadata', function checkResolution(){
const newResolution = {width: videoPlayer.videoWidth, height: videoPlayer.videoHeight}
const resolutionRatio = Math.min(newResolution.width / currentResolution.width, newResolution.height/currentResolution.height)
if(resolutionRatio < resolutionChangeThreshold){
console.warn('编码切换导致画质降低过大，取消切换，恢复到原始编码', currentCodec);
currentCodec = preferredCodec;
videoPlayer.src = playerConfig.args.url
}else {
console.log('编码切换完成，未发生画质降低')
}
videoPlayer.removeEventListener('loadedmetadata', checkResolution);
}, { once: true})
} else {
console.warn("未找到可用编码进行切换")
}
}
}
// 添加按钮事件监听
function addCodecButton() {
const actions = document.querySelector(".ytp-right-controls")
if (actions) {
const button = document.createElement('button');
button.classList.add('ytp-button');
button.textContent = "重置编码";
button.style.marginLeft = "10px"
button.onclick = () => {
console.log(`切换到原始编码${preferredCodec}`)
currentCodec = preferredCodec;
changeVideoCodec()
}
actions.appendChild(button);
}
}
addCodecButton()
if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', initObserver);
} else {
initObserver()
}
})();
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