title: Convert MP4 Version - FFmpeg
body: <p>I have two mp4 File:</p>
  <ol>
  <li>out.mp4: ISO Media, MP4 Base Media v1 [IS0 14496-12:2003]</li>
  <li>video/rio2016/finale/brasse/200.mp4: ISO Media, MP4 v2 [ISO 14496-14]</li>
  </ol>
  <p>How can I convert 1 to 2 (mp41 to mp42)?</p>