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I have problematic footage from diving due to my camera/SD card - every 4th or so frame is just black, and I want to replace all those black frames with either an interpolation between the previous and next frame or just duplicate the previous frame.

I found this question "remove black frames from vob files with ffmpeg", but I don't want to cut out the frames but instead want to interpolate between the two frames or duplicate the previous frame.

I think I might be able to get all the relevant positions with the black-frame filters etc, but what kind of actions would I use to replace those frames with an interpolation or a duplicate of the previous frame in a fully automatic way (so I only pass my movie file into the script)?

All I've found so far is the "shuffleframes" method, which I could somehow (how?) feed with the position of the black frames and then thereby duplicate the previous frame.

Demo footage detailing the probem can be found here.

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It's possible to have the black frames removed and earlier frames duplicated.

ffmpeg -i in.mp4 -vf blackframe=0,metadata=select:key=lavfi.blackframe.pblack:value=50:function=less -vsync cfr -c:a copy out.mp4

The blackframe filter analyses and registers the proportion of a frame's pixels which are black. The metadata filter keeps all frames which have at most 50% of pixels black. The removed frames create a gap in the video stream. So by setting the video sync method to constant frame rate, ffmpeg duplicates earlier (non-black) frames to fill in those gaps.

You'll have to experiment with the metadata selection value 50 to get the right threshold.

  • This is amazing. It pretty much achieves what I wanted to (I think). I wonder though how it a) handles cases where there is multiple directly following black frames b) why the output files are consistently longer than the input files (duration wise) – Hug Mar 17 '18 at 19:05
  • why does the output have a longer duration than the input? – Hug Mar 20 '18 at 9:45
  • Share full log. How much difference are we talking about? – Gyan Mar 20 '18 at 10:29
  • Hi, I'm sorry for the delay in replying. The difference is already some seconds, eg here pastebin.com/NfTVtEC0 original file: cl.ly/qSfM ffmpeged file: cl.ly/qSMr – Hug Mar 26 '18 at 19:34
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    Don't see a difference. Mediainfo shows format duration for original: 3 s 532 ms and for new file 3 s 534 ms – Gyan Mar 26 '18 at 19:53

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