title: HTML5 Video - what is the maximum playback rate?
body: <p>You can set the playback rate for a HTML5 video element:</p>
  
  <pre><code>var player = document.getElementById("video");
  player.playbackRate = 100;
  </code></pre>
  
  <p>The w3 spec does not define a limit. What is the maximum playback rate of the <code>&lt;video&gt;</code> element in Chrome and Firefox?  If the playback rate is not browser dependent, then what determines it?</p>
  
  <p><strong>Research:</strong></p>
  
  <p><a href="https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement">MDN HTML Media Element</a> says that some browsers will stop playing audio outside of a playback range between 0.25x - 4x.  It does not say whether the video element will continue to play video.</p>
  
  <p>YouTube's player supports speeds between 0.25x - 2x. This is a flash player, not an HTML5 video element, and I'm not interested in it.</p>
  
  <p>Personally, I have created a test page locally on my computer with a <code>&lt;video&gt;</code> element and a local video file. I can set the playbackrate to anything (e.g. 100), but the video does not seem to play faster than ~5x. I can't actually check the playbackrate speed, since it just returns the value "100" that I set.</p>