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Hi Florian,
I created an HDR to SDR 3dlut for MadVR, Displaycal correctly saves the file in the same location as my other 3dluts, however on the MadVR hdr tab with the option ‘convert HDR to SDR by using an external 3dlut’, when I try to load the 3dlut there I get an error ‘This 3dlut file does not match the input/output format required by MadVR’. The last time I’d made an HDR to SDR 3dlut was in Dec 2017 (can’t remember which version of Displaycal), but has something changed in the latest version? How do I generate an HDR to SDR 3dlut which will be accepted by MadVR?
Ok here’s something interesting. I was creating the file on my office PC and copying over to my HTPC. I just installed Displaycal etc on my HTPC and created directly there, and it it installed and loaded into MadVR no problem. When I check the file name, it says ‘BT.2020.HDR2SDR.3dlut’. On the office PC, with exactly the same settings, the filename is ‘BT.2020.HDR.3dlut’. This is the one that will not load in. I have no idea why on two different PCs using the same options to generate the profile, I get two different results. Odd.
Hi,
you’ve likely used the wrong slot in madVR. “HDR to SDR” 3D LUTs use a different slot than “process HDR” 3D LUTs. You can choose the madVR HDR 3D LUT type in DisplayCAL on the 3D LUT tab. Also make sure to use a recent madVR version, because previous versions did have some bugs with the HDR 3D LUT installation API.
I’ve also encountered the same error, MadVR v0.92.14 and DisplayCAL 3.6.
I’m creating a 3DLUT with the following settings:
And I receive “This 3DLUT file does not match the input/output format required by MadVR” when I try to select it as the BT.2020 3DLUT.
This is using my current profile, freshly created in DisplayCAL, and automatically selected in the 3DLUT Maker when I selected “Current profile” as the Destination Profile.
You are using the wrong section in madVR. You need to go to HDR, not calibration.
Your 3D LUT settings are not for HDR either. You need to set tone curve to SMPTE 2084 (roll-off) and choose the desired parameters.
Thanks for the reminder about the HDR/Calibration sections, I’d managed to actually do it once before correctly before but had confused myself.
However the 3DLUTs not being accepted by MadVR is still a strange problem. It seems your recommended method produces a 3DLUT which MadVR does not accept 🙂
I created another 3DLUT, this time using BT.2020 ST 2084 as the Source Profile, setting SMPTE 2084 (roll-off) with a target peak luminance of 100 cd/m, content colorspace of Rec. 2020, file format MadVR; all other settings unchanged.
If I try to apply it in the Calibration tab, MadVR refuses with the error, “This 3DLUT file does not match the input/output format required by madVR.” The same happens if I choose SMPTE 2084 hard clip, and it happens if I increase the target luminance to a value which makes the diffuse white ‘legal’.
Other 3DLUTs I have generated to test, using the same source profiles but with different settings (100% black output offset, or Gamma 2.2 tone curve) are accepted by MadVR OK.
I have access to an HDR display now, so I am using it to compare SDR transforms with native HDR playback. I am generating 3DLUTs both with VCGT enabled and disabled for comparison, as expected it makes no difference to MadVR accepting them or not.
If I try to apply it in the Calibration tab, MadVR refuses with the error, “This 3DLUT file does not match the input/output format required by madVR.” The same happens if I choose SMPTE 2084 hard clip, and it happens if I increase the target luminance to a value which makes the diffuse white ‘legal’.
You need to set these 3D LUTs in madVR under the HDR section, not calibration.
Other 3DLUTs I have generated to test, using the same source profiles but with different settings (100% black output offset, or Gamma 2.2 tone curve) are accepted by MadVR OK.
If you don’t use SMPTE 2084 roll-off or hard clip, you need to set the 3D LUT under the calibration section in madVR.
Hope this makes things clearer.
If I try to apply it in the Calibration tab, MadVR refuses with the error, “This 3DLUT file does not match the input/output format required by madVR.” The same happens if I choose SMPTE 2084 hard clip, and it happens if I increase the target luminance to a value which makes the diffuse white ‘legal’.
You need to set these 3D LUTs in madVR under the HDR section, not calibration.
Other 3DLUTs I have generated to test, using the same source profiles but with different settings (100% black output offset, or Gamma 2.2 tone curve) are accepted by MadVR OK.
If you don’t use SMPTE 2084 roll-off or hard clip, you need to set the 3D LUT under the calibration section in madVR.
Hope this makes things clearer.
Aha, yes! The MadVR interface doesn’t help to clarify things, I suppose what I’m doing is still fairly esoteric so the documentation and guides for doing this is patchy. It’s also been years since I even installed MadVR…
Your instructions work perfectly and the LUT gives the correct HDR->SDR results I was expecting. Thanks for clarifying things, I was getting confused between the various options – still learning the ropes with HDR, LUTs and the complex world of panel calibration. DisplayCal has proven incredibly useful already!
