Appears that the RRT global de-saturate step applied in AP1 drops to a gamut smaller than Rec2020. This seems to be ok when targeting Rec709/sRGB but not sure if this is future proof in the context of Rec2020. Seems like the reference ACES ODT for Rec709 at 48 nits ends up with gamut clipping when inputs to the RRT had covered the full positive part of AP1 space. Those working with sRGB/Rec709 primaries in the rendering pipeline might not have issues here depending on how much saturation is added during grading before the RRT. Guessing some people would rather be able to go nuts anywhere in the human perceptual space and have it smoothly map to the output display space?
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