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cameramanben / LUTCalc

Web App for generating 1D and 3D Lookup Tables (LUTs) for video cameras that shoot log gammas.
http://www.lutcalc.net
GNU General Public License v2.0
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spi3d Input Scaling #10

Open sjkgm opened 6 years ago

sjkgm commented 6 years ago

Input scaling can be specified in spi1d or Resolve.cube, but I also want spi3d to be able to specify input scaling. I want to make a LUT of Gammut Mapping that is not clamped by 0-1.

nick-shaw commented 6 years ago

Does spi3d support input range definition? Certainly all the spi3d LUTs in the OCIO repo use a 1D shaper to handle the input range, before applying a straight 0-1 cube.

sjkgm commented 6 years ago

I testing to convert Linear's OpenEXR to ARRI LogC WideGammut using LUT. Apply the two LUTs in the following order.

  1. Linear 3D LUT that only expand from sRGB to ARRIWideGamut
  2. Linear 2 ARRI LogC 1D LUT

Gamut expand needs to be applied in linear condition. Otherwise the result will not match the OCIO. In Resolve and Iridas.cube it was possible by specifying Input Range. I tried this with spi3d and 1d, but spi3d is output at 0 - 1, it is clamped at 1 and then Log C converted.

In the first place, is it impossible to specify Input range for spi3d?