This userscript will force all videos to use the h.264 codec rather than VP9/AV1.
// ==UserScript==
// @name Block AV1 & VP9
// @version 1.0
// @description This userscript will force all videos to use the h.264 codec rather than VP9/AV1.
// @author TZ Shuhag
// @license MIT
// @match *://www.youtube-nocookie.com/*
// @match *://www.youtube.com/*
// @match *://m.youtube.com/*
// @namespace https://greasyfork.org/en/users/1495563
// @icon https://raw.githubusercontent.com/tz-shuhag/HD.264/refs/heads/main/icons/video.png
// @run-at document-idle
// @unwrap
// @grant none
// ==/UserScript==
// Enable strict mode to catch common coding mistakes
"use strict";
// Force all videos to use h.264 (useful if you have a low spec machine when you load videos in 720p60)
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);
};
}