How to do 3D Lut color correction (.3DL .Cube) with avisynth(+) ?

[ErazorTT]

I'm having a lut which when using ffmpeg produces the expected behaviour, but when using the cube function returns unexpected things.
The following image shows the result, on the right part there are these waves which are unexpected, and are also not there using ffmpeg.


However when using ffmpeg I'm getting this:


Here are all files I am using:
hlg_test.7z

The command for ffmpeg is:
ffmpeg -i GreyRamp16bits.png -vf lut3d=lut_4000_3.0.cube -pix_fmt rgb48be GreyRamp16bits_converted.png

What is going on here, why the different results?

[Reel.Deel]

@ErazorTT

Does DGCube have the same problem? https://www.rationalqm.us/board/view...p=16092#p16092

[poisondeathray]

For reference, avs version , vpy version that it's based on , and Adobe get similar results

The difference is the default interpolation type for ffmpeg (tetrahedral) . Trilinear , pyramid, prism all produce the pattern to an extent

eg.
ffmpeg -i GreyRamp16bits.png -vf lut3d=lut_4000_3.0.cube:interp=trilinear -pix_fmt rgb48be GreyRamp16bits_converted_trilinear.png

[tormento]

Originally Posted by Reel.Deel

Does DGCube have the same problem?

Is it working for you? What card? Drivers?

[Reel.Deel]

Originally Posted by tormento

Is it working for you? What card? Drivers?

No, I am also getting access violation. I have not updated my drivers in a while so I was going to do that and see if it fixes the issue.

[ErazorTT]

Originally Posted by poisondeathray

For reference, avs version , vpy version that it's based on , and Adobe get similar results

The difference is the default interpolation type for ffmpeg (tetrahedral) . Trilinear , pyramid, prism all produce the pattern to an extent

eg.
ffmpeg -i GreyRamp16bits.png -vf lut3d=lut_4000_3.0.cube:interp=trilinear -pix_fmt rgb48be GreyRamp16bits_converted_trilinear.png

Oh that is a nice finding! So its the interpolation. Could this better interpolation be implemented into vscube (or DGCube for that matter)?

[ErazorTT]

Originally Posted by Reel.Deel

@ErazorTT

Does DGCube have the same problem? https://www.rationalqm.us/board/view...p=16092#p16092

I just found that DGCube needs 65x65x65 sized LUTs, so I tried again with one of that size. And yes, DGCube behaves that same as vscube.

[poisondeathray]

Originally Posted by ErazorTT

Could this better interpolation be implemented into vscube (or DGCube for that matter)?

It's debatable if a certain interpolation is going to be "better" for all situations;

But having more options is always welcome

You can try submitting a feature request
https://github.com/sekrit-twc/timecube/issues

[tormento]

Originally Posted by Reel.Deel

No, I am also getting access violation.

Generic size version has just been released.

[tormento]

Here is a new version supporting tetrahedral interpolation. It addresses ErazorTT's issue, as the artifacts do not occur with tetrahedral. Please read the new DGCube.txt file for details and be aware that the filter is now invoked as DGCube(). I'll add this to the timecube-derived Cube() filter as well. Also need to add Vapoursynth support to DGCube().

https://rationalqm.us/misc/DGCube.zip

[tormento]

Notice that in the latest version, no more avsresize is required and it got scorching fast.

[ErazorTT]

@tormento: Yup, this does now produce the intended results with these luts. Thanks!

[tormento]

Originally Posted by ErazorTT

Thanks!

Much better to thank the author.

Any bug report and testing is the most welcome.

[kedautinh12]

Originally Posted by tormento

https://rationalqm.us/misc/DGCube.zip

I wonder why don't DGCube have 2 ver x32 & x64

[tormento]

Originally Posted by kedautinh12

I wonder why don't DGCube have 2 ver x32 & x64

'cause x86 is getting more and more useless, especially with 4k.

[FranceBB]

Probably cause old x86 OS like my beloved XP don't really have drivers for modern NVIDIA GPUs so the DG plugins would have nowhere to run except for the old not so powerful NVIDIA GPUs...
I wish NVIDIA kept releasing drivers for XP x86 but it didn't happen, so nowadays I do most of my stuff via RDP from my XP to the remote Windows Server 2019 instance, especially after Tormento made me upgrade my stable Windows 10 Enterprise workstation to the unstable crap called Windows 11 Enterprise which one day upgraded itself only to end up blue screening in loop, thus making me lose every program installed.

[tormento]

Originally Posted by FranceBB

especially after Tormento made me upgrade my stable Windows 10 Enterprise workstation to the unstable crap called Windows 11 Enterprise which one day upgraded itself only to end up blue screening in loop, thus making me lose every program installed.

Oh, dear.

You use crappy hardware and you blame me.

Windows 11 Enterprise x64 here since day 1 (on Insider Channel too) and no major hiccups.

[FranceBB]

Originally Posted by tormento

Oh, dear.

You use crappy hardware

-> I'm broke, as simple as that xD

[FranceBB]

Hi there Donald,
currently it isn't possible to pick which kind of interpolation is used to produce the result in Cube() (I'm talking about the CPU version).
Would it be possible to introduce an option in Cube() like String Interpolation where it can have one of the following values Interpolation="Tricubic", Interpolation="Trilinear", Interpolation="Tetrahedral", where the default is Tetrahedral?

So I imagine the usage to be like:

Cube("myLUT.cube", fullrange=true, Interpolation="Tetrahedral")

The reason is that I'm currently dealing with a brand new BBC LUT for HLG to BT709 SDR.
I used to use the 8a, which performs clipping, but some majors want me to use the new 9c which works in Studio RGB (Limited TV Range) and preserves overshootings (so the BT709 will have out of range whites and blacks and it won't clip them).

The issue I have with it is that the interpolation Cube() is doing is different from the interpolation the major is using and they will therefore reject the result.


AVS Script:

LWLibavVideoSource("D:\4K_Ama\05_DI SERVIZIO - EBU UHD HDR COLOR BARS\EBU_HDR_COLOUR_BARS_2160p_v210.mov")

propClearAll()

#From 4:2:2 16bit planar Narrow Range to RGB Planar 16bit Narrow Range
z_ConvertFormat(pixel_type="RGBP16", colorspace_op="2020:std-b67:2020:limited=>rgb:std-b67:2020:limited", resample_filter_uv="spline64", dither_type="error_diffusion", use_props=0)

#From HLG to BT709 with 16bit precision
Cube("A:\avdb\Server\encoder\encoder\Processors\avs_plugins\LUTs\9c_HLG_BT709_Type3_Display_DownMapping_SuperWhite_nocomp-v1_5.cube", fullrange=true)

#From RGB 16bit planar Narrow Range to YUV420 8bit planar Narrow Range with dithering
z_ConvertFormat(pixel_type="YUV420", colorspace_op="rgb:709:709:limited=>709:709:709:limited", resample_filter_uv="spline64", dither_type="error_diffusion", use_props=0)

Here's the result (Left interpolation done by Cube() - Right interpolation done by the major who's selling us the content):

https://i.imgur.com/hyky5sZ.png



Before you say "CUDA!" please note that our workflows are based on 100+ scalable VMs in the cloud that are shut down and only woken up when they need to perform a job and then they're shut down and they're CPU only, so we have no way to use CUDA other than on the legacy MAM on prem which will be discontinued soon-ish.


Thank you in advance,
Frank

[kedautinh12]

DGCube 22/09/30
https://rationalqm.us/misc/DGCube.zip