I pushed a new version CAM DRT v045-pex to my prototype repo. This version brings the following changes:
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Introduce “reach mode” chroma compression. The chroma compression space is now used to find out how far to reach out (the limit for chroma expansion/compression). The reach limit is normalized with the cusp of the same space. The primaries of the chroma compression space is changed at the same time. This significantly improves the inverse, as well as guarantees the chroma compression will not expand or compress colorfulness beyond that space. This is using same technique as @alexfry’s reach mode gamut mapping.
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Make noise reduction optional and disabled by default. The new transforms doesn’t really increase noise anymore so noise reduction may be redundant.
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Change gamut mapping parameters. Adds also clamp for maximum M that the transform handles. This is 2x the maximum M value for 10000 nit display. That value and any value above that would map only to display white or be always out of gamut even after gamut mapping. This avoids NaNs with the gamut mapper quadratic.
Rec.709 Inverse
v045-pex:
v044:
Effect of chroma compression to chromaticities
Input chromaticities:
scaled chromaticities:
fully chroma compressed:
