slow ffmpeg's images per second when creating video from images

ffmpeg, screenshot

Solution

You can change video speed by adjusting the “presentation time stamp” (PTS). In your case:

ffmpeg -f image2 -i screenshot_%5d.png -vcodec mpeg4  -vf "setpts=5*PTS" demo.avi

You'll get video, which plays 5 times slower, than normal video.

If you want to make it 5 times faster:

ffmpeg -f image2 -i screenshot_%5d.png -vcodec mpeg4  -vf "setpts=(1/5)*PTS" demo.avi

Problem

I have a series of screenshots from a demo that I want to put in a video. I am using ffmpeg for this purpose. The command is `ffmpeg -f image2 -i screenshot_%5d.png -vcodec mpeg4 demo.avi`. However, the video length is shorter than what I want, and it moves very fast. How do I specify how many images per second I want? I tried the `-r` argument but that did not work.

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