title: "Media resource FILEPATH/FILENAME.mp4 could not be decoded." while trying to play h264 encoded files on Firefox 35
body: <p>We use mp4 files using the h264 codec on our server to play videos. The files in FF prior to FF35 worked fine, they work in IE8+, and Chrome. In FF35 we now get the following message in the console</p>
  
  <pre><code>Media resource FILEPATH/FILENAME.mp4 could not be decoded.
  </code></pre>
  
  <p>If we then load the resource directly we get</p>
  
  <pre><code>Video can't be played because the file is corrupt.
  </code></pre>
  
  <p>Is there something we have to do to the mp4 files to get them working in FF35? This behavior has been replicated on FF35 on OS 10.6.8-10.9, Windows 7, and Windows 8.</p>