[FFmpeg-user] Zoom out/scale down dynamically

Gyan gyandoshi at gmail.com
Fri Sep 14 07:54:36 EEST 2018

On Fri, Sep 14, 2018 at 9:29 AM astian <astian at e-nautia.com> wrote:

> Well, I'm not sure what you mean. Pad doesn't seem very dynamic to me, I
> know that it has an eval=frame option, but according to the manual there
> is no frame-number variable that I could exploit.

Pad the video beforehand, usually with a transparent colour, then use
zoompan. Since your new frame is much larger, you can simulate a zoom-out
of the image, since with the padding, your zoom value doesn't need to drop
below 1.

However, you can't output these frames of differing sizes, as ffmpeg will
resize them to a fixed size prior to encoding. However, you can use them in
overlay, where the transparent padding gets hidden and you get the
effective result.


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