title: FFMPEG Generate N Evenly Spaced PNG Screenshots
body: <p>I am trying to generate 8 screenshots for an uploaded video using FFMPEG. I currently have:</p>
  
  <blockquote>
    <p>ffmpeg -i Trailer-720p.mov -r .2
    -vcodec png Preview-%d.png</p>
  </blockquote>
  
  <p>Which generates a screenshot every 5 seconds. How can I add the ability to generate a screenshot for frames distributed over a percentage of total time. Thanks. Furthermore, is it possible to generate a screenshot at 50% for example? Thanks.</p>