View Issue Details
ID | Project | Category | View Status | Date Submitted | Last Update |
---|---|---|---|---|---|
0000424 | madVR | bug | public | 2016-07-30 23:42 | 2018-01-14 18:30 |
Reporter | huhn | Assigned To | madshi | ||
Priority | normal | Severity | minor | Reproducibility | always |
Status | closed | Resolution | no change required | ||
Platform | x64 | OS | windows 10 | OS Version | 14366 |
Summary | 0000424: reconstruct and other chroma scaler are adding very visible artefatcs when a 3d LUT is used | ||||
Description | this problem is pretty huge and complicated but easy to reproduce. sample 3d lut nv12 frame and a screenshoot created with reconstruct sharp without a 3D LUT: http://www.file-upload.net/download-11810700/3dlut.7z.html | ||||
Steps To Reproduce | load 1 frame CC.mkv use reconstruct sharp for chroma scaling load/set absolut 2.4 gamma.3dlut as a 3D LUT. | ||||
Additional Information | most chroma scaler are showing artifacts. but reconstruct sharp and bicubic 150 are very terrible. there are some artifacts without the 3D LUT too. maybe these are two bugs and the 3D lut is just highlighting these issue. the 3D LUT isn't triggering this bug if a screenshoot created using reconstruct sharp is used as a source and than altered with a 3D LUT. screens: "fine" reconstruct sharp: https://abload.de/img/reconstructsharplna79.png "broken" reconstruct sharp + 3D LUT: https://abload.de/img/3dlut2kyxh.png "fine" screenshoot+ 3D LUT: https://abload.de/img/rgbimage3dlut36lbi.png i don't see how my 3D LUT itself could be the cause here. | ||||
Tags | No tags attached. | ||||
madVR Version | 90.22 | ||||
Media Player (with version info) | mpc-hc 1.7.10 x64 | ||||
Splitter (with version info) | lavfilter 68.1 | ||||
Decoder (with version info) | lavfilter 68.1 | ||||
Decoding | Software | ||||
Deinterlacing | none (progressive) | ||||
DXVA2 Scaling Active | no | ||||
Aero / Desktop Composition | On | ||||
Problem occurs with mode | all modes | ||||
GPU Manufacturer | NVidia | ||||
GPU Model | 960 | ||||
GPU Driver Version | 369.00 | ||||
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My best guess is that the chroma scalers produce some out-of-gamut colors, which then have Red, Green or Blue values which lie outside of the valid 16-235 range. Your 3dlut might not handle these cases very well. Making a screenshot pretty much cuts off BTB/WTW, because a screenshot is always stretched to black 0 and white 255. Possible solutions: 1) Try to create a better 3dlut which handles BTB/WTW values better. 2) Use a custom pixel shader which cuts off BTB/WTW. |
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the 3D LUT is a TV RGB (CLIP WTW) 3D LUT. don't forget that the issue is visible without a 3D LUT but it is very very minimal compared with a 3D LUT. i don't have a clue what should be changed in the 3D LUT creation. it was done with newest dispalCAL 0000001:0000002 week ago. i can try to create a 3D LUT without WTW clipping but that doesn't make sense to me. but it is an easy task to do. i will try to check that next weekend. edit: i tried pre and post resize: 16-235 -> 0-255 [SD][HD] 255 -> 16-235 the problem was still there. |
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Try a custom pixel shader with something like "return clamp(tex2D(sampler, tex), 16.0/255.0, 235.0/255.0);" to clip BTB/WTW. Does that fix the problem? |
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sorry i don't have a clue about shaders. i get : C:\Program Files\MPC-HC\Shaders\clipping shader.hlsl(1,1): error X3000: syntax error: unexpected token 'return' |
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Well, you need a bit of frame around that line of code. This should work: sampler s0 : register(s0); float4 main(float2 tex : TEXCOORD0) : COLOR { return clamp(tex2D(s0, tex), 16.0/255.0, 235.0/255.0); } |
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the brightness is dropping a lot but on the first view all 3D LUT related issues are gone. the brown cross is still damaged by reconstruct but it has some strange are artefacts in the first place: https://abload.de/img/reconstructfixc7bsl.png i ask fhoech about this. a WTW clipping 3D LUT or a 3D LUT in general shouldn't do that. |
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Oh, I forgot that custom pixel shaders run in PC levels and not TV levels. Change the clamp to "0.0, 1.0" instead of "16.0/255.0, 235.0/255.0", that should take care of the brightness drop. Does that still fix the issue? If so, the 3dlut BTB/WTW handling is definitely the cause of the issue. |
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with "0.0, 1.0" the 3D LUT related issue is gone. so it is clearly the 3d LUT. |
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Good to hear, then we can close this issue? |
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i don't known. looks like argyllcms 3D LUTs in general shouldn't be feed with out of gamut colors: [QUOTE=fhoech][QUOTE=huhn]could you have a look at this issue: [url]http://bugs.madshi.net/view.php?id=424[/url] this is a problem with out of gamut colors created by chroma scaler and the 3D LUT can't deal with this properly. the 3D LUT is a TV RGB 16-235 (CLIP WTW) 3D LUT. log: [url]http://www.file-upload.net/download-11839782/madVR2016-07-2010-120.3127x0.329ySXYZLUT.7z.html[/url][/QUOTE] Hi, you'll have to explain what the issue is, the bug report is not clear to me at all. Also note that code values 0 and 255 in digital video are reserved for sync, and should thus be passed through by a 3D LUT unchanged (and this is what the Argyll LUTs do, not sure if it is related). If the chroma scaler creates values in that range, it probably needs to be changed to leave sync untouched.[/QUOTE] but i guess this can be closed there is nothing more for me to add about this problem. i don't known if you are right now interested in the other chroma scaler artefacts. |
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What other artifacts to you mean? |
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the image host has a 502 bad gateway. so i have to make new ones later today. they are the "same" artefacts seen with the 3D LUT but a lot weaker. reconstruct sharp and bicubic 150 (not an important chroma scaler i know) are showing them and maybe more. |
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Those are probably ringing artifacts. |
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reconstruct sharp and or sharp AR doesn't show any difference. reconstruct sharp: https://abload.de/img/reconstructsharp81sb2.png spline3 AR: https://abload.de/img/spline3arwqs46.png it gets amplified when scaled to UHD. cropped UHD screens i used super xBR 100 to scale them to UHD. reconstruct sharp: https://abload.de/img/croppedreconstructshaxxsao.png spline3 AR: https://abload.de/img/croppedspline3ar4cska.png |
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Sorry for the very late reply. Hmmmm... Which artifacts do you mean in the cropped UHD screens exactly? I can see a faint blue line on the left side of those brown squares. Is that what you mean? If so, that looks like ringing to me. I'm not sure if there's anything I can do about it. FWIW, I'm planning to replace recontruct with my own NGU based algorithm in the future, which hopefully won't have such artifacts. reconstruct is not my algo, so it's hard for me to fix problems with it. |
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when i look at them i see a red tint in the white lines between the squares with reconstruct. sorry it has been a while. which is i guess the same artefact as the 3d LUT one just a lot less notable. "the 3D LUT isn't triggering this bug if a screenshoot created using reconstruct sharp is used as a source and than altered with a 3D LUT." taking this old comment into account this issue may just come from processing images in limited range without BTB WTW clipping. |
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I've looked at both images with a pixel peeper. I can see the red tint, but it's in both images. For some reason, to the human eye it seems stronger in the "reconstruct" image, but the pixel peeper doesn't lie. It says: FFEBE8 vs FFEAE6 Which means RGB (255, 235, 232) vs (255, 234, 230). So both images have the Red subpixel fully maxed out while Green and Blue are not maxed out, which results in the red tint. The red tint is ever so slightly deeper in the reconstruct image, but technically, it's only a very small difference. |
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well i don't know what to say about this. it looks quite different on left part. which is mostly notice thanks to the 3D LUT issue. |
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Well, it looks somewhat more reddish to me, too (although I didn't originally notice it at all, until you pointed it out to me), but the actual RGB numbers don't differ much. In any case, I don't really want to spend much time debugging "reconstruct" issues, it's not "my" algorithm, and I think it would be wiser to spend the time on a better replacement instead in the future, no? |
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after all this time i just wonder if this comes from WTW/BTB numbers.it doesn't seem to happen if the image isn't scaler afterwards. but fine to me to leave it at this. |
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It could have to do with WTW/BTB and "reconstruct" might make things worse somehow. Could also be ringing, or a combination of WTW/BTB + ringing. In any case, if the issue still exists once I've implemented the NGU based successor to "reconstruct", we can revisit the issue then. So I'll close this one for now. |
Date Modified | Username | Field | Change |
---|---|---|---|
2016-07-30 23:42 | huhn | New Issue | |
2016-08-10 18:32 | madshi | Note Added: 0001424 | |
2016-08-10 21:51 | huhn | Note Added: 0001425 | |
2016-08-10 22:10 | madshi | Note Added: 0001426 | |
2016-08-10 22:27 | huhn | Note Edited: 0001425 | |
2016-08-10 22:45 | huhn | Note Added: 0001427 | |
2016-08-10 22:54 | madshi | Note Added: 0001428 | |
2016-08-10 23:13 | huhn | Note Added: 0001429 | |
2016-08-11 00:51 | madshi | Note Added: 0001430 | |
2016-08-11 09:17 | huhn | Note Added: 0001432 | |
2016-08-11 10:24 | madshi | Note Added: 0001433 | |
2016-08-16 14:40 | huhn | Note Added: 0001443 | |
2016-08-16 14:46 | madshi | Note Added: 0001444 | |
2016-08-16 15:11 | huhn | Note Added: 0001445 | |
2016-08-16 15:18 | madshi | Note Added: 0001446 | |
2016-08-16 22:28 | huhn | Note Added: 0001447 | |
2018-01-14 17:04 | madshi | Note Added: 0002052 | |
2018-01-14 17:04 | madshi | Assigned To | => madshi |
2018-01-14 17:04 | madshi | Status | new => feedback |
2018-01-14 17:44 | huhn | Note Added: 0002063 | |
2018-01-14 17:44 | huhn | Status | feedback => assigned |
2018-01-14 17:53 | madshi | Note Added: 0002066 | |
2018-01-14 17:53 | madshi | Status | assigned => feedback |
2018-01-14 18:04 | huhn | Note Added: 0002067 | |
2018-01-14 18:04 | huhn | Status | feedback => assigned |
2018-01-14 18:18 | madshi | Note Added: 0002071 | |
2018-01-14 18:18 | madshi | Status | assigned => feedback |
2018-01-14 18:24 | huhn | Note Added: 0002073 | |
2018-01-14 18:24 | huhn | Status | feedback => assigned |
2018-01-14 18:30 | madshi | Note Added: 0002075 | |
2018-01-14 18:30 | madshi | Status | assigned => closed |
2018-01-14 18:30 | madshi | Resolution | open => no change required |