[FFmpeg-user] How to change video fps from 29.970 to 25?

FFMPEG_UL ffmpeg at rgbaz.eu
Mon Sep 1 22:06:04 CEST 2014


Ok, here it is: Sample 29.970 fps file which I want to convert to 25fps: 
http://artnmedia.pl/damian/fps/sample-29.970fps.mp4 Damian Głodny 
<damian <at> artnmedia.pl> writes:
>>> I tried many ffmpeg filters like pullup, telecine, fieldmatch,
>>> decimate, but my output video always stuttering.
>
> Ok, that sample is "30" fps progressive. (I am going to use 30 for 29.97=30000/1001.)  It has 30 complete video frames per second. If you want to reduce it 25 fps
>
...
> 3) Magically turn the 6 frames of progressive video into 5 frames of progressive video showing the same scene evenly spaced out. Requires Magic(tm).
>
>
Hi

Your Magic might be called "optical flow".
It's technique where the movement of (all) pixels in the image is turned 
into
a vector. Once you have these vectors you can tell them for instance to 
take
move slower or faster. This generates very smooth speed changes.
There's a huge lot of other things you can do once you have this 
information.

There's an open source project that seems to work with ffmpeg here:
http://slowmovideo.granjow.net

I haven't tried this one myself. I have used commercial versions of the
algorithms.

Maybe it will give you better results.

greets
Arno



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