title: Slice a video with ffmpeg based on frame position
body: <p>I'd like to extract a slice of video from a video. Unfortunately, I do not have the start time position and duration to run ffmpeg like so:</p>
  
  <pre><code>ffmpeg -sameq -ss [start_seconds] -t [duration_seconds] -i [input_file] [outputfile]
  </code></pre>
  
  <p>Instead, I have the first and the last frame number. So... is it possible to slice a mp4 video with ffmpeg based on frame position?</p>