Notice of Meeting - ACES Gamut Mapping VWG - Meeting #24 - 8/13/2020

Discussions - ACESNext VWG – Gamut Compression/Mapping
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ACES Gamut Mapping VWG Meeting #24

Thursday, August 13, 2020
9:30am - 10:30am Pacific Time (UTC-4:30pm)

Please join us for the next meeting of this virtual working group (VWG). Future meeting dates for this month include:

  • 8/20/2020, 5pm
  • 8/27/2020, 9:30am

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3 posts were split to a new topic: Objective tests of the gamut mapper

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Recap:

  • @Pablo_Garcia - used the DCTL implementation on a current project with good results, tweaked per clip for some more creative uses
  • Known bugs:
    • Shadow rolloff still has effect at 0
    • Hexagonal mode inverse is incorrect right now, implementation is possible but not pretty
    • Proposal to move forward without the hexagonal mode, no real objections
  • @daniele presented an issue with the reds - start from a “perfect” camera that fills the spectral locus, compress. Quite a noticeable red gap
    • You don’t see it with the RRT, but visible still in T-cam
    • Also found an artifact issue on tanh with inverting all negative values
  • Objective testing:
    • @KevinJW : how important is P3 based on Daniele’s tests around saturated reds? Could start with P3 and invert to see where it lands as a test gamut to compress.
    • @daniele : round trip inversion tests - how many can we do before we get unacceptable errors (what is that metric?)
    • @joseph - time dependent, willing to test around color purity in arri measurements
    • What happens if you use the RICD & Harald’s LED spectra measurements? Similar to Daniele’s already demonstrated tests
    • @nick : for testing should we reset / set all values to the same number and let the user find what works best for them?
    • @Alexander_Forsythe : should we do a pair comparison test or other objective user test measurements?
    • Defaults need definition - what should the mapping do in a default state - these are our next steps!

Recording and Transcript