title: What does 'Past duration X.XXX too large' mean?
body: <p>When encoding H.264 using ffmpeg I get the following type of warnings en masse:</p>
  
  <pre><code>Past duration 0.603386 too large
  Past duration 0.614372 too large
  Past duration 0.606377 too large
  </code></pre>
  
  <p>What do they mean? I have not found anything clear online or in the ffmpeg documentation.</p>