GradCurve filter can be used to edit the gradation curves similar to the curves function of painting programs. It is a powerful tool that allows you to do some basic correction like brightness, contrast and gamma as well as a wide range of advanced color correcting and manipulations.
GradCurve is a VapourSynth c++ plugin converted from the VirtualDub c++ plugin Gradation Curves(
http://forum.doom9.org/showthread.php?t=133191)
There is a working test version of GradCurve on github:
https://github.com/jieiku/GradCurve
windows dll:
https://github.com/jieiku/GradCurve/.../GradCurve.dll
project files that can be used for testing:
http://www.mediafire.com/file/9nc2et...j/gradcurve.7z
Disclaimer: I have only tested amp/acv files with pmode=1 (RGB + R/G/B), so if you come across a bug please let me know.
Thanks so very much to everyone that has helped me throughout this thread, I really apprciate it.
Also, I welcome any improvements/changes, so please share