title: Can't use MediaElementAudioSource due to CORS access restrictions
body: <p>I'm trying to use the Audio API, and I can't play audio.</p>
  
  <p><a href="https://jsfiddle.net/m305au2d/" rel="nofollow noreferrer">Here</a> is a reproduction of the issue. If you open the js console, after triggering play/pause on the video, you'll see a message saying <code>VM374:1MediaElementAudioSource outputs zeroes due to CORS access restrictions for https://s3.amazonaws.com/mettavr/dev/VfE_html5.mp4</code> and no audio is played. (it's not an error, but just an info log)</p>
  
  <p>I've found a few SO questions like <a href="https://stackoverflow.com/questions/31308679/mediaelementaudiosource-outputs-zeros-due-to-cors-access-restrictions-local-mp3">this</a> one or <a href="https://stackoverflow.com/questions/31083704/mediaelementaudiosource-outputs-zeroes-due-to-cors-access-restrictions">this</a> one. It sounds that the flag <code>crossorigin</code> should be set to <code>anonymous</code> and that the server permissions should allow cross origin.</p>
  
  <p>I'm serving the file from a S3 bucket that seems to have opened enough permissions:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"&gt;
      &lt;CORSRule&gt;
          &lt;AllowedOrigin&gt;http://*&lt;/AllowedOrigin&gt;
          &lt;AllowedOrigin&gt;https://*&lt;/AllowedOrigin&gt;
          &lt;AllowedMethod&gt;POST&lt;/AllowedMethod&gt;
          &lt;AllowedMethod&gt;GET&lt;/AllowedMethod&gt;
          &lt;AllowedMethod&gt;HEAD&lt;/AllowedMethod&gt;
          &lt;MaxAgeSeconds&gt;3000&lt;/MaxAgeSeconds&gt;
          &lt;ExposeHeader&gt;Content-Range&lt;/ExposeHeader&gt;
          &lt;ExposeHeader&gt;Content-Length&lt;/ExposeHeader&gt;
          &lt;AllowedHeader&gt;*&lt;/AllowedHeader&gt;
      &lt;/CORSRule&gt;
  &lt;/CORSConfiguration&gt;
  </code></pre>
  
  <p>Still, I can't play my audio</p>
  
  <p>======</p>
  
  <p>Edit 1: clarify when the info message appears</p>