title: using ffmpeg to replace a single frame based on timestamp
body: <p>Is it possible to CLI ffmpeg to replace a specific frame at a specified interval with another image? I know how to extract <em>all</em> frames from a video, and re-stitch as another video, but I am looking to avoid this process, if possible.</p>
  
  <p>My goal:</p>
  
  <ul>
  <li>Given a video file input.mp4</li>
  <li>Given a PNG file, image.png and given its known to occur at exactly a specific timestamp within input.mp4</li>
  <li>create out.mp4 with image.png replacing that position of input.mp4</li>
  </ul>