Remove sequentially duplicate frames when using FFmpeg

Question

Is there any way to detect duplicate frames within the video using ffmpeg?

I tried -vf flag with select=gt(scene,0.xxx) for scene change. But, it did not work for my case.

Answer 1

Use the mpdecimate filter, whose purpose is to "Drop frames that do not differ greatly from the previous frame in order to reduce frame rate."

• This will generate a console readout showing which frames the filter thinks are duplicates.

  ffmpeg -i input.mp4 -vf mpdecimate -loglevel debug -f null -
  

• To generate a video with the duplicates removed

  ffmpeg -i input.mp4 -vf mpdecimate,setpts=N/FRAME_RATE/TB out.mp4
  

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The setpts filter expression generates smooth timestamps for a video at FRAME_RATE FPS. See an explanation for timestamps at What is video timescale, timebase, or timestamp in ffmpeg?