chronium based only
As of
// ==UserScript==
// @name YouTube - Live Recoder
// @namespace https://greasyfork.org/ja/users/941284-ぐらんぴ
// @version 2025-08-04
// @description chronium based only
// @author ぐらんぴ
// @match https://*.youtube.com/*
// @icon https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @grant none
// @run-at document-start
// @require https://greasyfork.org/scripts/433051-trusted-types-helper/code/Trusted-Types%20Helper.js
// @license MIT
// ==/UserScript==
let $s = (el) => document.querySelector(el), $sa = (el) => document.querySelectorAll(el), $c = (el) => document.createElement(el)
let recorder, chunks = [], isRecording = false, seconds = 0, timerInterval;
window.addEventListener("yt-navigate-finish", e => {
if(e.detail.pageType == "watch"){
if(e.detail.response?.playerResponse?.videoDetails?.isLive){// live
//filename
const now = new Date();
const month = String(now.getMonth() + 1).padStart(2, '0');
const day = String(now.getDate()).padStart(2, '0');
let name = e.detail.response.playerResponse.videoDetails?.author
let title = e.detail.response.playerResponse.videoDetails?.title
//let videoId = e.detail.response.playerResponse.videoDetails?.videoId
let addon = $s('.ytp-right-controls')
let btn = $c('button');
btn.textContent = ` [RECORD]`;
btn.className = "GRMP";
btn.style.cursor = "pointer";
btn.style.color = "white";
btn.style.background = "none";
btn.style.border = "none";
btn.style.cursor = "pointer";
btn.addEventListener("click", () => {
const video = $s("video");
if(!video){
alert("Video element not found.");
return;
}
if(video.paused || video.readyState < 3){
video.play().catch(err => console.warn("Video play failed:", err));
}
if(!isRecording){
try{
const stream = video.captureStream();
if(!stream){
alert("Failed to capture stream.");
return;
}
recorder = new MediaRecorder(stream);
chunks = [];
recorder.ondataavailable = e => chunks.push(e.data);
recorder.onstop = () => {
clearInterval(timerInterval);
btn.textContent = ` [RECORD]`;
const blob = new Blob(chunks, { type: 'video/webm' });
const url = URL.createObjectURL(blob);
const a = document.createElement('a');
a.href = url;
try{
a.download = name + "_" + title + "_" + month + "/" + day + ".webm";
}catch(e){ //alert('Could not get filename', e)
a.download = location.search.replace('?v=', '') + "_" + month + "/" + day + ".webm";
};
a.click();
};
recorder.start();
isRecording = true;
seconds = 0;
btn.textContent = formatTime(seconds);
timerInterval = setInterval(() => {
seconds++;
btn.textContent = formatTime(seconds);
}, 1000);
}catch(e){ alert("Recording failed: " + e);
}
}else{
recorder.stop();
isRecording = false;
clearInterval(timerInterval);
btn.textContent = ` [RECORD]`;
}
});
if(!$s('.GRMP')) addon.appendChild(btn);
function formatTime(sec){
const m = String(Math.floor(sec / 60)).padStart(2, '0');
const s = String(sec % 60).padStart(2, '0');
return ` [${m}:${s}]`;
}
}
}
});