ITU-R BT.709
Kb = 0.0722, Kr = 0.2126
Y = 0.299×R + 0.587×G + 0.114×B
Cb = 0.564×(B - Y)
Cr = 0.713×(R - Y)
Y ∈ [0, 1] is the luma (luminance)
Cb is the blue chroma
Cr is the red chroma
