Simple script to create color grading / color correction presets and export them to a 3DLUT. The goal is to then use it on videos.
Capabilities and qualities:
- white-balance when testing on images;
- hue-to-hue maps for dark and bright tones separately;
- functions use the cylindrical CIEluv colorspace, which focus on keeping the same perceived luminosity of each color after hue shifts;
- saturation map with respect to brightness;
- lightness map with respect to brightness;
- locally boost or decrease the lightness within an interval of hue and lightness;
- locally boost or decrease the saturation within an interval of hue and lightness;
- considerably good performance;
Change the parameters in arguments.py to tweak the colors. The presets are all given by RGB and HSV/L values, since these are very simple to colorpick and understand. The HSV/L (range: hue from 0° to 360°, saturation and value/lightness from 0% to 100%) numbers are all converted to cylindrical CIEluv. Run
python makeLUT.py
to generate a new LUT file in .cube format. This will ignore any white-balance presets in arguments.py. Ideally, you should apply the LUTs generated by this script on footage that's already white-balanced. To test on an image, run
python makeLUT.py --test=/path/to/image.png
on your terminal.
If you use any video editor, you should be able to import the 3DLUT file with ease. Here I included the vapoursynth script cc.py to accomplish this. To avoid artefacting due to possible extreme transformations the 3DLUT might do, a fast denoiser is applied to separate any noise or film grain from the footage. The noise is added back to the video after the color correction, and finally a deband filter is applied. To preview the cc.py script, run on your terminal:
./vspipepreview.sh /path/to/video.avi
You can edit vspipepreview.sh to pipe the script to a raw y4m file or to ffmpeg to get a proper encode.
( untouched | white-balance + 3DLUT exported by the script )
