[FFmpeg-user] Stretch/Scale only center of overlay image

[Michael Koch]

Am 13.02.2020 um 02:36 schrieb Hans Carlson:
> Is it possible to stretch/scale only the center part of an overlay image?
>
> I don't mean the middle section of a video, I mean only the center 
> part of a single image (png) that will be overlayed onto a background, 
> such that the left and right sides are relatively unchanged, but the 
> center of the image is stretched to fit the new size.

Do you mean a continuous zoom like image warping? I have a few examples 
in my book (search for "image warping"):
http://www.astro-electronic.de/FFmpeg_Book.pdf

Michael