Hi Pfile!
A very difficult task, and you mananged to get an excellent viedeo!
To your questions.
The PixInsight Animation script does an Autohistogram to all images with one mouseclick.
When i make videos i let the cropped and registered images run with PI-animation using autohistogram.
In the background i capture the video from the PC-Screen with the software "MAGIX".
Another solution for getting the the same background brightness for all images is PIxelMath.
If i want for example the background at 0.18
The Pixelmath expression could be:
(Symbols define):
B, Diffa, Diffb
PixelMath RGB/K Expression:
B = 0.18;
Diffa = median($T) - B;
Diffb = B - median($T);
iif(median($T) > B, ($T) - Diffa, ($T) + Diffb)
PixelMath works nicely with Image container.
For sure there are other solutions but this one seems to work for me.
Aloha
Gerald