Output Transforms Architecture VWG - July 10th, 2024

The recording and notes from meeting #160 are now available.

I can just say that Display P3 is exactly as sRGB just with different primaries. And the factory shipped calibration on macOS and IpadOS in fact implements the pure 2.2 Gamma function in P3 mode. And it is good so.
If we want to correct the errors done in the past, we should deprecate the piecewise function on the encoding side and finally be compatible with video


Given that we have one group of people who want to deprecate the piecewise function for Display P3, and one who want to deprecate 2.2 gamma, it seems clear that the situation is exactly the same as for sRGB. Both forms exist out in the wild now. I believe this means we need to support both.

As discussed in the meeting, I will write up my findings and report them to Apple. But I don’t believe the situation will change in the near future. It seems unlikely that Apple will change the behaviour of all their Display P3 devices. And even if they did, there would be large numbers of systems out there that people would not upgrade (it’s hardly a security patch) so would keep behaving as they always have.

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