title: Reporting duplicated frames with FFmpeg
body: <p>I am looking for a method to report (not just detect and remove) duplicated frames of video detected by FFmpeg  - similar to how you can print out blackdetect, cropdetect, silencedetect, etc. </p>
  
  <p>For example:</p>
  
  <p>ffmpeg -i input.mp4 -vf blackdetect -an -f null - 2>&amp;1 | grep blackdetect > output.txt</p>
  
  <p>Outputs something like:</p>
  
  <p>[blackdetect @ 0x7f8032f03680] black_start:5.00501 black_end:7.00701 black_duration:2.002</p>
  
  <p>But there's no "dupedetect" filter as far as I know, so I'm looking for any ideas/workarounds to get a read of where frames are duplicated.</p>