I have 12hour long video ( 30fps ). I want to shrink it to just 5 mins.

12 hour * 30fps => total 1296000 frames
5 mins * 60ps => total 18000 frames
That means automatically pick every 72nd frame from the video. ( I don't know, my maths is really bad ;) )

Can you please suggest any free software to do this job?

  • Please specify your input and desired output video format (container + actual encoding). Your calculation looks good to me.
    – ComFreek
    Commented Sep 6, 2015 at 9:54

1 Answer 1


You should be able to use ffmpeg for this with the framestep filter.

  • Free
  • Cross Platform
  • Supports most video types
  • Awesome. I think this is exactly what I needed. Also can I combine 300 clips of 3 minutes each into one using ffmpeg? Or any other software please suggest. Commented Sep 6, 2015 at 22:00
  • ffmpeg will also handle appending video clips, including replacing or mixing over the soundtrack, can cope with combining videos in different formats into one, change frame rate, aspect ratio, add captions, insert stills, etc. Commented Sep 7, 2015 at 5:31
  • It is almost 6 hours and ffmpeg is still converting. 12hours long video. Am I doing something wrong or does it really take that long. ( I have core i7, 8GB RAM, 2GB nvidia ) Commented Sep 8, 2015 at 5:02
  • I wouldn't expect it to take that long - I would suggest testing with a much smaller video first - say 3-5 minutes - as an input, (but with the same format, frame rate, etc.), to get your settings correct. Commented Sep 8, 2015 at 5:08
  • You might find it worth using ffmpeg -t 300 your_big_file.ext first_five.ext where ext is the same for both, then you can experiment with first_five. Commented Sep 8, 2015 at 5:40

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