[FFmpeg-user] Vignetting filter tuning.

[Evert Vorster]

Hi there.

I have a project page on
https://github.com/evertvorster/dualfisheye2equirectangular_ffmpeg_remap

It makes use of Ffmpeg's remap filter and nona's ability to create the maps
that the remap filter uses.
Unfortunately, the twin lenses of my Samsung Gear 360 is plagued with a
very distinct vignetting.

I have been playing with the vignetting filter of ffmpeg to try and correct
for the vignetting before actually remapping the video.

Unfortunately, it appears that there is not enough control over the filter.
I switch it into it's backwards mode to remove vignetting, and move the x
offset to be the middle of whichever lens I am trying to correct for.

However, the filter either brightens the entire image, or is not strong
enough on the edges.

Is the filter completely linear in strength from the center, or is there a
way to specify a curve?

Kind regards,
-- 
Evert Vorster
Isometrix Acquistion Superchief