[issue45775] Implementation of colorsys.rgb_to_yuv and vice versa

[STINNER Victor]

STINNER Victor <vstinner at python.org> added the comment:

> A link to an authoritative reference with the formulas would be necessary to merge this.

The PR says: "ATSC BT.709 standard constants".

For exmaple, I found:
https://en.wikipedia.org/wiki/Rec._709#Luma_coefficients

"When encoding Y’CBCR video, BT.709 creates gamma-encoded luma (Y’) using matrix coefficients 0.2126, 0.7152, and 0.0722 (together they add to 1)."

----------
nosy: +vstinner

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue45775>
_______________________________________