Regarding the ARRI bar image that was discussed in the meeting, where P3 shows “less detail” in the bottles than Rec.709, I think the gamut mapper could explain that difference. With Rec.709 there’s more out of gamut colors, and more compression will happen, and the lightness mapping that happens in the gamut mapper will map the color darker. With P3 it will compress less, and possibly doesn’t compress in that example at all. The gamut mapper doesn’t preserve the original luminance of the out of gamut color. I haven’t checked if this was the case.