🚀 go-pugleaf

Miklos,

do we now really talk about YCbCr ?

The conversion from RGB to Y is a widely accepted standard,
but alas.., as Aandi had pointed out, there is not only one RGB
space.
The matrices, which you can find everywhere else refer exactly
to the NTSC space and are valid for expected Gamma distorted
image data (this means: linear light space data C=RGB are stored
as modified values C�=C^/(1/2.2). It is a compensation for a
monitor which should have then the inverse transfer function).

Everybody should be aware that the transformation of C� data
to any other color space is wrong, but the YCbCr conversion is
done like this "by tradition".

Y is practically OK, a B/W television would show a reasonable
gray image. Cb and Cr don�t have a meaning, they are just
mathematical constructions (3 variables in, 3 Variables out).
The distribution was IMO chosen in a way that the overall band-
width in TV channels is mimimized.

Best regards --Gernot Hoffmann