title: ffmpeg animated gif overlay, animation starts before specified 'between'
body: <p>I am adding an animated gif as an overlay to a video with a command like this:</p>
  <p><code>ffmpeg -y -i video.mp4 -i overlay.gif -filter_complex &quot;[0:v][1:v] overlay=38:11:enable='between(t,1.35,15.042000)'&quot; -pix_fmt yuv420p -c:a copy -safe 0 output.mp4</code></p>
  <p>In that command I'm asking it to show the gif from 1.35 to 15, and that works insofar as the overlay is only shown between those times, but it's as if the animation starts before it reaches 1.35, because the bit of the animation before that point doesn't ever appear on the screen.  The start of the animation is missing from the final video.</p>
  <p>Tried in ffmpeg-20180925-a7429d8 and ffmpeg-N-100581-ga454a0c14f</p>