This userscript will mark both videos and notifications as focus mode, semi-advanced CSS tweaks, forcing h.264 codec on all videos along with other tweaks to prevent most of system resources.
// ==UserScript==
// @name Forcing YT to use advanced tweaks to compile less resources
// @version 2025.11.04
// @description This userscript will mark both videos and notifications as focus mode, semi-advanced CSS tweaks, forcing h.264 codec on all videos along with other tweaks to prevent most of system resources.
// @author LegendCraftMC
// @license MIT
// @match https://www.youtube.com/*
// @match https://m.youtube.com/*
// @match https://www.youtube-nocookie.com/*
// @match https://www.youtube-nocookie.com/embed/*
// @match https://studio.youtube.com/live_chat*
// @exclude /^https?://\S+\.(txt|png|jpg|jpeg|gif|xml|svg|manifest|log|ini)[^\/]*$/
// @namespace https://greasyfork.org/en/users/933798
// @icon https://www.youtube.com/favicon.ico
// @unwrap
// @run-at document-idle
// @unwrap
// @inject-into page
// @allFrames true
// @grant none
// ==/UserScript==
// Add config flags to disable both animations and ambient mode functionally
// Enable strict mode to catch common coding mistakes
"use strict";
// Define the flags to assign to the EXPERIMENT_FLAGS object
const flagsToAssign = {
// Disable animated features (except for sub and like buttons)
web_animated_actions: false,
web_animated_like: false,
web_animated_like_lazy_load: false,
smartimation_background: false,
// Disable ambient lighting
kevlar_measure_ambient_mode_idle: false,
kevlar_watch_cinematics_invisible: false,
web_cinematic_theater_mode: false,
web_cinematic_fullscreen: false,
enable_cinematic_blur_desktop_loading: false,
kevlar_watch_cinematics: false,
web_cinematic_masthead: false,
web_watch_cinematics_preferred_reduced_motion_default_disabled: false,
// More tweaks
kevlar_refresh_on_theme_change: false
};
const updateFlags = () => {
// Check if the EXPERIMENT_FLAGS object exists in the window.yt.config_ property chain
const expFlags = window?.yt?.config_?.EXPERIMENT_FLAGS;
// If EXPERIMENT_FLAGS is not found, exit the function
if (!expFlags) return;
// Assign the defined flags to the EXPERIMENT_FLAGS object
Object.assign(expFlags, flagsToAssign);
};
// Create a MutationObserver that calls the updateFlags function when changes occur in the document's subtree
const mutationObserver = new MutationObserver(updateFlags);
mutationObserver.observe(document, { subtree: true, childList: true });
// Hide the number of notifications to prevent any annoyances
// Save the original descriptor of document.title
const originalTitleDescriptor = Object.getOwnPropertyDescriptor(Document.prototype, 'title');
// Create a custom getter and setter
Object.defineProperty(document, 'title', {
get: function() {
return originalTitleDescriptor.get.call(this);
},
set: function(newValue) {
// Remove the (#) with regex.
const interceptedValue = newValue.replace(/^\(\d+\)\s?/, "");
// Call the original setter
originalTitleDescriptor.set.call(this, interceptedValue);
}
});
(function() {
'use strict';
const style = document.createElement('style');
style.type = 'text/css';
style.innerText = '.yt-spec-icon-badge-shape--type-notification .yt-spec-icon-badge-shape__badge{display:none;}';
document.head.appendChild(style);
})();
// Disable both 'trailer autoplay' and 'automatic pause' features
(function main() {
'use strict';
document.createElement = new Proxy(document.createElement, {
apply(target, that, args) {
if (args[0]?.toLowerCase() !== 'video') return Reflect.apply(target, that, args);
const video = Reflect.apply(target, that, args);
video.addEventListener('loadstart', () => {
const channel = document.querySelector('ytd-channel-video-player-renderer');
if (channel?.contains(video)) video.pause();
}, { passive: true });
return video;
},
});
}());
Object.defineProperties(document, { /*'hidden': {value: false},*/ 'webkitHidden': {value: false}, 'visibilityState': {value: 'visible'}, 'webkitVisibilityState': {value: 'visible'} });
setInterval(function(){
document.dispatchEvent( new KeyboardEvent( 'keyup', { bubbles: true, cancelable: true, keyCode: 143, which: 143 } ) );
}, 60000);
// Force all videos to use h.264 (useful if you have a low spec machine when you load videos in 720p60)
// Modified from https://github.com/erkserkserks/h264ify/tree/master/src/inject as of 2018-05-16 (MIT license)
var mse = window.MediaSource;
if (mse){
// Set up replacement for MediaSource type support function
var nativeITS = mse.isTypeSupported.bind(mse);
mse.isTypeSupported = ourITS(nativeITS);
}
// Here's the replacement
function ourITS(fallback){
// type is a string (hopefully!) sent by the page
return function (type) {
if (type === undefined) return '';
// We only reject VP9
if (type.toLowerCase().indexOf('vp9') > -1) return '';
if (type.toLowerCase().indexOf('vp09') > -1) return ''; // Added 12/20/2019
// Let Firefox handle everything else
return fallback(type);
};
}
// Add CSS tweaks (disables frosted glass transparency on topbar to revert back to the old topbar color, reducing the bottom gradient in the video player, etc...)
(function() {
let css = `
/* Topbar tweaks */
ytm-mobile-topbar-renderer.frosted-glass,
ytm-pivot-bar-renderer.frosted-glass,
ytm-feed-filter-chip-bar-renderer.frosted-glass,
#background.ytd-masthead, #frosted-glass.ytd-app,
#left-arrow-button.ytd-feed-filter-chip-bar-renderer,
#right-arrow-button.ytd-feed-filter-chip-bar-renderer {
background: var(--yt-spec-base-background) !important;
backdrop-filter: none !important;
-webkit-backdrop-filter: none !important
}
#left-arrow.ytd-feed-filter-chip-bar-renderer:after {
background: linear-gradient(to right, var(--yt-spec-base-background) 20%, rgba(255, 255, 255, 0) 80%) !important
}
#right-arrow.ytd-feed-filter-chip-bar-renderer:before {
background: linear-gradient(to left, var(--yt-spec-base-background) 20%, rgba(255, 255, 255, 0) 80%) !important
}
ytd-button-renderer.ytd-feed-filter-chip-bar-renderer {
background: transparent !important
}
div#end.style-scope.ytd-masthead .yt-spec-icon-badge-shape--style-overlay.yt-spec-icon-badge-shape--type-cart-refresh .yt-spec-icon-badge-shape__badge {
color: #fff !important
}
.yt-spec-icon-badge-shape--type-notification .yt-spec-icon-badge-shape__badge {
display: none !important
}
/* Player tweaks */
#cinematics.ytd-watch-flexy {
display: none !important
}
.ytp-gradient-top, .ytp-gradient-bottom {
height: 50px !important;
padding: 0
}
.ytp-big-mode .ytp-gradient-top, .ytp-big-mode .ytp-gradient-bottom {
height: 61px !important;
height: 0 !important
}
.ytp-gradient-top {
background: linear-gradient(to bottom, #0009, #0000) !important
}
.ytp-gradient-bottom {
background: linear-gradient(to top, #0009, #0000) !important
}
/* Remove every unwanted compact renderer in related section and limit the number of related videos to 9 (plus it disables the 'endless scrolling' feature) */
#related ytd-compact-video-renderer,
#related ytd-compact-playlist-renderer,
#related ytd-compact-radio-renderer,
#related yt-lockup-view-model,
#related ytd-channel-renderer,
ytd-watch-flexy ytd-reel-shelf-renderer,
ytd-watch-flexy ytd-rich-section-renderer,
#related ytd-continuation-item-renderer,
#related #continuations {
display: none !important
}
#related yt-lockup-view-model:nth-of-type(1),
#related yt-lockup-view-model:nth-of-type(2),
#related yt-lockup-view-model:nth-of-type(3),
#related yt-lockup-view-model:nth-of-type(4),
#related yt-lockup-view-model:nth-of-type(5),
#related yt-lockup-view-model:nth-of-type(6),
#secondary #related yt-lockup-view-model:nth-of-type(7),
#secondary #related yt-lockup-view-model:nth-of-type(8),
#secondary #related yt-lockup-view-model:nth-of-type(9) {
display: flex !important
}
/* Remove minimal annoyances and other tweaks */
ytd-ad-slot-renderer,
ytm-ad-slot-renderer,
ad-slot-renderer,
ytd-promoted-video-renderer,
ytm-promoted-video-renderer,
ytd-promoted-sparkles-web-renderer,
ytm-promoted-sparkles-web-renderer,
ytd-text-image-no-button-layout-renderer,
ytm-text-image-no-button-layout-renderer,
ytd-merch-shelf-renderer,
ytd-compact-movie-renderer,
ytd-mealbear-promo-renderer,
ytd-video-quality-promo-renderer,
tp-yt-iron-overlay-backdrop.opened {
display: none !important
}
.ytd-ghost-grid-renderer,
.info-skeleton,
.meta-skeleton,
#ghost-cards,
#ghost-comment-section,
#related-skeleton {
display: none !important
}
ytd-watch-metadata.ytd-watch-flexy {
padding-bottom: 36px !important
}`;
if (typeof GM_addStyle !== "undefined") {
GM_addStyle(css);
} else {
let styleNode = document.createElement("style");
styleNode.appendChild(document.createTextNode(css));
(document.querySelector("head") || document.documentElement).appendChild(styleNode);
}
})();
// Other tweaks (includes both memory leak fix and service worker prevention)
(() => {
const Promise = ((async () => { })()).constructor;
const ets = `
yt-navigate
yt-navigate-start
yt-page-type-changed
yt-player-updated
yt-page-data-fetched
yt-navigate-finish`.trim().split(/\s+/)
const fn = () => {
if (location.search.includes('pp=')) {
let oUrl = location.pathname + location.search;
let nUrl = location.pathname + location.search.replace(/([?&])pp=[^=&?]+\b(\&|)/, (a, p, q) => {
return !q ? '' : p
});
if (oUrl !== nUrl) history.replaceState(history.state, '', nUrl);
}
}
const fh = () => {
fn();
Promise.resolve().then(fn);
}
for (const et of ets) {
document.addEventListener(et, fh, false);
}
})();
if (typeof ServiceWorkerContainer === "function" && typeof ServiceWorkerRegistration === "function" && typeof (ServiceWorkerContainer.prototype || 0).getRegistrations === 'function' && !ServiceWorkerContainer.prototype.register767) {
const filterSW = (e) => {
const url = typeof e === 'string' ? e : `${((e || 0).active || 0).scriptURL}`;
return url.endsWith('/sw.js');
};
const makeReject = true;
const unRegisterAll = () => {
const sw = ((typeof navigator === 'object' ? navigator : null) || 0).serviceWorker || 0;
if (sw && typeof sw.getRegistrations === 'function') {
sw.getRegistrations().then(e => e.length >= 1 && Promise.all(e.filter(filterSW).map(e => e.unregister().catch(console.warn)))).catch(console.warn);
}
}
let i = 0;
const scriptCollection = document.getElementsByTagName('script');
(new MutationObserver((mutations, observer) => {
if (typeof yt !== 'object' || scriptCollection.length === 0) return;
if (i < 394 && document.readyState === "complete") i = 394;
if (++i > 400) {
observer.disconnect();
return;
}
if (typeof navigator !== "object") return;
if (!('serviceWorker' in navigator) || !navigator.serviceWorker) return;
if (typeof navigator.serviceWorker.getRegistrations !== "function") return;
unRegisterAll();
})).observe(document, { subtree: true, childList: true, attributes: true });
ServiceWorkerContainer.prototype.register767 = ServiceWorkerContainer.prototype.register;
ServiceWorkerContainer.prototype.register = function (url, ...args) {
if (!filterSW(`${url}`)) {
return this.register767(...arguments);
}
if (i < 394) i = 394;
Promise.resolve().then(unRegisterAll);
return new Promise((resolve, reject) => {
makeReject && setTimeout(() => {
reject(new TypeError("Failed to register a ServiceWorker."));
}, Math.round(1300 + 1700 * Math.random()) + 0.125);
});
};
Promise.resolve().then(unRegisterAll);
unRegisterAll();
}
(() => {
/** @type {globalThis.PromiseConstructor} */
const Promise = (async () => { })().constructor; // YouTube hacks Promise in WaterFox Classic and "Promise.resolve(0)" nevers resolve.
const insp = o => o ? (o.polymerController || o.inst || o || 0) : (o || 0);
const indr = o => insp(o).$ || o.$ || 0;
const getThumbnail = (thumbnails) => {
let v = 0, n = (thumbnails || 0).length;
if (!n) return null;
let j = -1;
for (let i = 0; i < n; i++) {
const thumbnail = thumbnails[i];
let k = thumbnail.width * thumbnail.height;
if (k > v) {
j = i;
v = k;
}
}
if (j >= 0) {
return thumbnails[j];
}
return null;
}
// let normal = false;
const ytDOMWM = new WeakMap();
Object.defineProperty(Element.prototype, 'usePatchedLifecycles', {
get() {
let val = ytDOMWM.get(this);
if (val === 0) val = false;
if (val && !this.isConnected && !this.classList.contains('style-scope')) val = false;
return val;
},
set(nv) {
let control = false;
const nodeName = (this?.nodeName || '').toLowerCase();
switch (nodeName) {
case 'yt-attributed-string':
case 'yt-image':
if (this?.classList?.length > 0) {
control = false;
} else {
control = true;
}
break;
case 'yt-player-seek-continuation':
// case 'yt-iframed-player-events-relay':
case 'yt-payments-manager':
case 'yt-visibility-monitor':
// case 'yt-invalidation-continuation': // live chat loading
case 'yt-live-chat-replay-continuation':
case 'yt-reload-continuation':
case 'yt-timed-continuation':
control = true;
break;
case 'yt-horizontal-list-renderer':
case 'ytd-rich-grid-slim-media':
case 'ytd-rich-item-renderer':
case 'yt-emoji-picker-renderer':
// if (!normal) {
// control = true;
// }
break;
case 'yt-img-shadow':
if (nv) {
const cnt = insp(this);
const url0 = getThumbnail(cnt?.__data?.thumbnail?.thumbnails)?.url
if (url0 && url0.length > 17) {
// normal = true;
control = true;
Promise.resolve(0).then(() => {
const url = getThumbnail(cnt?.__data?.thumbnail?.thumbnails)?.url || url0;
cnt.$.img.src = `${url}`;
});
} else {
control = false;
}
}
break;
default:
control = false;
// if (nv) {
// if (!normal) {
// Promise.resolve(0).then(() => {
// if (!normal && (this.classList.contains('style-scope') || this.isConnected === true)) {
// normal = true;
// }
// });
// }
// }
}
if (control) nv = 0;
ytDOMWM.set(this, nv);
return true;
},
enumerable: false,
configurable: true
});
})();