Here is a link to a Google Colab version of the code to generate (a slightly tweaked version of) the test pattern I showed in the meeting. It also includes CIExy plots of the original and compressed pattern.
Because OpenImageIO is needed to write an ACES compliant EXR, and that will nor run in a Colab, I have commented out the OpenImageIO based lines, and added some code which uses ImageIO to write a 32-bit PIZ compressed EXR.
Here is a proper ACES EXR of the test pattern, together with gamut compressed versions made using ctlrender and BlinkScript.
For testing an implementation the following command line (based on what @ChrisD and @doug_walker created for the CLF VWG) should be used:
oiiotool gc_test_image_v006_comp_ctl.exr --dup gc_test_image_v006_comp_blink.exr --absdiff --swap --abs --maxc 0.1 --div --rangecheck 0,0,0 .002,.002,.002 -o /tmp/tmp.exr
This will produce the following output if the images match:
0 < 0,0,0
0 > .002,.002,.002
2073600 within range
We would be grateful if people could take a look at the proposed test pattern, so we can get feedback for discussion in this week’s meeting. In particular, input from @michaelch, @bill, @ptr, @daniele and @doug_walker would be greatly appreciated.