 Recommendation ITU-R BT.709-6

Primary source: www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.709-6-201506-I!!PDF-E.pdf

Verified locator: June2015, Parameter values for the HDTV standards for production and international programme exchange, primary ITU publication. Printed page3 item1.1 specifies nonlinear primary conversion; page4 items3.2–3.4 specify primed-signal coefficients0.2126/0.7152/0.0722, colour-difference divisors1.8556/1.5748 and219/224/16/128 digital scales. Published edition cited explicitly; nonlinear luma is distinguished from photometric luminance.