[FFmpeg-user] Filter for smoothening gradual luminance changes?

[Markku Tavasti]

On 16.04.2017 15:08, Markku Tavasti wrote:
> towards camera, and endig to darkness. So exposure changes gradually,
> but problem is that on such cameras, change is annoying clear, sudden
> change. Therefore, I'd like to smoothen that so that it is not that sudden.
>
> See example what I mean https://youtu.be/vOVYZAcWpZE?t=23s

Another example, where changes are not gradual, to one direction, and 
video is speeded up more, so result is flickering:

https://www.youtube.com/watch?v=k1FY2HiPa2g

One option is to write all frames as pictures to disk, and then run 
timelapse-deflicker.pl for them, and make video from those pictures. 
However, that will take much time and disk space.

--Tavasti