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I'm blending every 16 frames down to 1 to drastically shorten a timelapse video.

However, it runs very slowly. Is it blending every frame with the 15 following frames, then dropping 15/16 of the frames? That would mean it is doing 16x as much work as it needs to.

If so, is there a better (faster) way to blend frames that doesn't do redundant work?

-vf "tmix=frames=16:weights='1',select='not(mod(n\,16))',setpts=0.0625*PTS"
Giacomo1968
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Benjamin H
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  • How about just increasing the frame rate times 16? Seems that would be the simplest way to achieve what you are looking for. – Giacomo1968 Sep 08 '20 at 03:23
  • Increasing the frame rate does display the file faster, but then when I post it anywhere that only supports up to 60fps, they drop the extra frames. I'd like to blend them. – Benjamin H Sep 08 '20 at 05:50

1 Answers1

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Seems like you are doing too much work to blend frames; that should just be a natural part of converting and not a big/complex param in a command.

I mean think about taking an image and scaling it down; you don’t have to do a custom algorithm to change the pixels when going from 10 inches to — let’s say — 1 inch in size. It’s just an inherent part of the process.

Looking at this answer here I believe there is a simpler way to approach this by using the fps video filter in FFmpeg. I believe — for your purposes — the command can be simplified to be just something like this:

ffmpeg -i input.mp4 -filter:v fps=fps=1/16 output.mp4

The key part is the -filter:v fps=fps=1/16 option.

Look at this other answer for another explanation on how the fps filter works.

And here are some other ideas based on the advice in this answer here on Stack Overflow…

This one uses the FFmpeg minterpolate filter:

ffmpeg -i input.mp4 -vf minterpolate=fps=1/16 output.mp4

And this one uses the FFmpeg framerate filter:

ffmpeg -i input.mpg -vf framerate=fps=1/16 output.mp4
Giacomo1968
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