Resolve LUTs not working in Mini Converter SDI to HDMI 6G

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beninsler

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  • Joined: Tue Oct 29, 2013 7:05 pm

Resolve LUTs not working in Mini Converter SDI to HDMI 6G

PostWed Sep 22, 2021 2:45 am

I'm trying to build a LUT for our post production pipeline to lift an SDI signal coming into our SDI to HDMI 6G Mini Converter, and I'm running into some behavior that I can't explain or understand. Any 33 point LUT that I save out of Resolve, even a no-change LUT that applies no adjustments to the image, results in odd color artifacting that appears to be the result of bad image math. Bright regions of the image (like an out of focus practical light in the BG) receive a hard white or pink ring around them when the LUT is applied. Other areas of the frame - that don't necessarily appear to be bright or highly saturated, receive bright pink, purple or green pixelation (see sample image - please forgive the moire effect from me taking a photo of my monitor).

I'd assume I'm trying to do something beyond my scope of color science understanding, but the hard part for me to understand is that, in a scramble to find a solution, I've built some 33 point LUTs in Photoshop, and these work just fine. Also, the pre-installed LUTs on the SDI to HDMI 6G Mini Converter appeared to work without artifacts before I overwrote them, and the stock Resolve LUTs also work without creating artifacts. It appears that it is only LUTs generated in Resolve that are causing the issue.

The artifacts are introduced regardless of the signal being processed. This LUT is intended to modify a 4K HDR P3-D65 signal. However we've also tested the numerous experimental LUTs on a 1920x1080 Rec 709 signal. The above behavior is observed on both signals.

Thanks so much!

Ben

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Salva Vinets

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  • Real Name: Salva Viñets

Re: Resolve LUTs not working in Mini Converter SDI to HDMI 6

PostTue Sep 28, 2021 8:29 am

Would love to know if anybody had success loading a calibration LUT(33points) on this device and if it's properly working.

Best of luck on your issue Beninsler!
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beninsler

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Re: Resolve LUTs not working in Mini Converter SDI to HDMI 6

PostWed Nov 10, 2021 7:30 am

I'm pretty disappointed that there has been zero response to this in a month and a half, considering that all aspects of this question deal with the interplay between Blackmagic-only products. Presumably one Blackmagic product can make the correct LUT for another Blackmagic product to read.

Anyone at Blackmagic care to weigh in? I'd like to know how to build LUTs for these boxes correctly in Resolve.

Thanks,

Ben
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Steve Fishwick

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Re: Resolve LUTs not working in Mini Converter SDI to HDMI 6

PostWed Nov 10, 2021 11:39 am

It rather looks like your luts are translating legal to full levels. I would check your settings in Resolve in this regard.

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