Verification of External 3d LUT

[maximilian1 SourceForge]

Hi All

I’m looking for a way to verify a 3D LUT created in dispcalGUI through Resolve and then loaded into an AJA LUT Box. The way I understand this, verification inside dispcalGUI effectively applies the LUT before any signal is generated, and so signals coming out of Resolve during a verification are post LUT. This is great to check the numbers in the LUT out of DispcalGUI, however I’m looking for a way to test the LUT after it has been loaded in an external device like the AJA LUT box. Anyone got any ideas? The “Report on Uncalibrated Display” option is always greyed out for me, but I thought that might be an option.

Workflow:

Meter: I1 DisplayPro

3D LUT generated from DispcalGUI using Resolve as a pattern generator.

3D LUT loaded into AJA LUT box and then placed inline between SDI output from Resolve and external SDI monitor.

Thanks in advance for any help you can provide.

Cheers, Max

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[Florian Höch]

Hi,

I’m looking for a way to test the LUT after it has been loaded in an external device like the AJA LUT box.

Go to the “Verification” tab and uncheck the “Devicelink profile” box (the rest of the options should already be correct, but make sure “Simulation profile” and “Tone curve” are set to the same settings as during 3D LUT generation and “Use simulation profile as target profile” is checked).

[maximilian1 SourceForge]

Hi Florian

Thanks for your previous help. I’ve followed your instructions several times. However I’m getting wildy different verification reports depending on whether I’m using Devicelink, or verifying from an external LUT with device link off. Devicelink is accurate but the external LUT verification is not. It seems as if the Assumed White point does not change, or is not measured properly, and thus appear too warm. I’ve attached both verification reports if you wouldn’t mind having a look.

This display has had interactive display adjustment turned off as there is no display adjustment on this particular monitor. I have read somewhere else on the forum that this was a previous issue that had been solved.

Process:

1500 patch test with Resolve and Pattern Generator
No display adustment
1d LUT applied in the 3DLUT options
3d LUT loaded into AJA LUT Box
Verification done with LUT Box in line and no device link – poor results
Verification done with LUT Box bypassed and devicelink on – good results

Thanks again for any help you can give me.

Cheers, Max

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[Florian Höch]

Hi,

it looks a bit like an issue with levels scaling. I think the 3D LUT input and output encoding needs to be set to full range (0..255) because the AJA Box already takes into account video levels, so having it in the 3D LUT as well might lead to errors. Try to re-create the 3D LUT with input and output encoding set to full range (you can re-create the 3D LUT without re-measuring by unchecking “Create 3D LUT after profiling” on the “3D LUT” tab).

[maximilian1 SourceForge]

Thanks Florian, this woked a treat!

Max

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