input:the input colour buffer in camera rgb
output:the output in rec2020 rgb
clut:(optional) the color lookup table generated by the mkclut utility
picked:(optional) route picked colour for white balancing source in here
abney:(optional) point to data/abney.lut for hue constant saturation and gamut compression, see the gamut.pst preset
spectra:(optional) point to data/spectra.lut for hue constant saturation and gamut compression, see the gamut.pst preset
