PQ reference white has been changed form 50% to 58% quite some time back

[erazortt]

Following BT.2408 the reference white for PQ HDR has been changed to 203 nits. HCFR should follow that, and change it from its current value of around 50% value to the about 58% value.

See Chapter 2.1 in here:
https://www.itu.int/pub/R-REP-BT.2408-4-2021

Since the value of 203nits is given in table 1 (page 6) for both PQ and HLG we can assume that 203 is an exact value. From this it follows that the value of 58% is approximated and should be exactly 0.580688881.

The two values that will need to be changed are:

• 94.37844 which is the luminosity of the reference white in nits, this will need to go to 203
• 0.5022283 which is the percentage of the maximum value, this will need to go to something like 0.580688881.

This change should also be reflected in the generator, where for example the primaries and secondaries, as well as the saturations should ask for that 58% luminosity instead of the current value of 50%.