Tampermonkey script for speeding up web media

speed-up.js

// ==UserScript==
// @name         force‑1.25×‑every‑media
// @match        *://*/*
// @run-at       document-start
// ==/UserScript==
(() => {
  const RATE = 1.5;

  /* ----------  HTMLMediaElement ---------- */
  const desc = Object.getOwnPropertyDescriptor(
      HTMLMediaElement.prototype, 'playbackRate');

  // hard‑override the setter so any “set to 1.0” gets ignored
  Object.defineProperty(HTMLMediaElement.prototype, 'playbackRate', {
    get() { return desc.get.call(this); },
    set(_) { return desc.set.call(this, RATE); }   // always RATE
  });

  // make sure play() kicks in with the right rate even on blob rewrites
  const origPlay = HTMLMediaElement.prototype.play;
  HTMLMediaElement.prototype.play = function (...args) {
    if (this.playbackRate !== RATE) desc.set.call(this, RATE);
    return origPlay.apply(this, args);
  };

  /* ----------  Web‑Audio (AudioBufferSourceNode) ---------- */
  if (window.AudioBufferSourceNode) {
    const origStart = AudioBufferSourceNode.prototype.start;
    AudioBufferSourceNode.prototype.start = function (...args) {
      try {
        // multiply any preset rate by 1.25; if none, just set it
        const p = this.playbackRate;
        const ctxTime = this.context.currentTime;
        const nowVal = p.value || 1.0;
        p.setValueAtTime(nowVal * RATE, ctxTime);
      } catch (_) { /* some nodes are read‑only; ignore */ }
      return origStart.apply(this, args);
    };
  }

  /* ----------  fix elements already in the DOM ---------- */
  document.addEventListener('DOMContentLoaded', () => {
    document.querySelectorAll('video,audio')
            .forEach(m => { if (m.playbackRate !== RATE) desc.set.call(m, RATE); });
  });
})();