madVR - high quality video renderer (GPU assisted)

[Soxbrother]

New problem : inside Mediaportal, the font size is too big ( windows screen settings is at 150%)
Now when I set it at 100%, everything is as it should be, but now I only hear audio and have no video, :(
What to do now ?

[Warner306]

Not sure I'm getting what you're trying to say. Isn't tonemapping only needed because of TVs having a too low peak brightness?
As far as I know mastering monitors don't do any tonemapping, so non-bright scenes should look similar to what I see with dynamic tonemapping disabled.
Then why would it be a good thing to brighten up darker scenes?

I did a small test to see how much LGs dynamic tonemapping messes with non-bright scenes.
I just displayed a 50 nits movie scene in the background while running a grayscale sweep in HCFR.
The result shows exactly what my eyes have been seeing when using LGs dynamic tonemapping. Large deviations from the PQ, even in the lower range. With it turned off it at least follows it nicely up to like 125 nits.

You could be right, but I don't know if your test is accurate. If it is the newest model, it would be less likely the display would be deviating from the curve. Your graph would show raised blacks rather than true black in many scenes because it is lifting the bottom of the curve. That isn't supposed to be the case, unless the display is trying to compensate for poor near black response.

You are somewhat misunderstanding how a static tone curve works. The display will take the static metadata value (usually 1,000 nits mastering peak or 4,000 nits mastering peak) and plot a single tone curve for the entire movie. That curve never changes; it is static, so the entire movie will roll-off the brightness depending on the aggressiveness of the chosen curve. In other words, the whole movie will be slightly darker than intended (tone mapped). There is no relief from this tone curve at any point. The display will follow the PQ curve up to a certain point and add a knee point where the roll-off begins.

A dynamic tone curve will use the source peak as the target for the tone curve, but it will decrease and increase the roll-off as the scene peak changes. So scenes within the brightness of the display (700 nits) can be shown 1:1 with the PQ curve because tone mapping is not required (tone mapping could be disabled or significantly reduced). Scenes that are close to the source peak should look similar to a static tone curve and would use a standard roll-off. The tone mapping roll-off is necessary to present the intended contrast of the scene to make it look HDR when the display lacks the necessary luminance to show all values within its available dynamic range. It is a no-no to go above the PQ curve at any time, but going below the PQ curve is what is considered tone mapping.

I think the area LG needs to improve upon compared to the competition is in blending these changes in brightness. They may be moving the knee point for the tone curve too often or are doing a poor job of fluctuating the roll-off. I haven't heard of any accounts from the reviews I've read of the display boosting the brightness above the PQ curve. The only display that I know does that is the Samsung Q9FN, which consistently boosts 0-100 nits.

madVR is also using a dynamic tone curve with brightness changes, but those changes may be masked better. However, the fluctuations in brightness will be more noticeable when using a range of 0-700 nits than 0-120 nits, so dynamic tone mapping on a bright display can always be capable of some visible shifts in brightness. This is done to keep the image as bright as possible throughout the presentation inline with the original mastered values. No one likes a dark image, so tone mapping compression should be minimized.

[j82k]

It is a no-no to go above the PQ curve at any time, but going below the PQ curve is what is considered tone mapping.


But that is exactly what LG's dynamic tonemapping is doing for pretty much any scene that is below the TVs peak brightness. It heavily goes above the PQ curve and that why I think it's crap. It's like what samsung is doing.

And it's not even good at revealing otherwise clipped highlights. MadVR does a much better job at this.

[Warner306]

I don't think this is intended, but it could be doing some monkey business with the source, or you need an HDR calibration. Like I said, the newer the model, the better. Panasonic and Sony are known to be better at this.

[chros]

I did a small test to see how much LGs dynamic tonemapping messes with non-bright scenes.
Thanks for the graphs! Which LG TV is it?
I really don't get why people keep praising LG's dynamic tone mapping. It's terrible and I don't ever use it. It behaves almost like a dynamic contrast setting
It seems exactly like the "dynamic contrast" for SDR TVs :)

[Alexkral]

A final issue with a lot of displays, specifically home TVs, is the manufacturers deliberately deviating from the HDR specification, in an attempt to generate what they view as 'better' images.

This obviously means the same source footage will be seen very differently on different displays, even if the displays are defined as being 'calibrated'.

However, this issue is actually something we have sympathy for, because as mentioned previously above, the PQ HDR specification is flawed, as the standard is 'absolute', and includes no option to increase the display's light output to overcome surrounding room light levels. The result is that in less than ideal viewing environments, where the surrounding room brightness level is relatively high, the bulk of the HDR image will appear very dark, with shadow detail potentially becoming very difficult to see.

Many home TV manufacturers therefore deliberately 'distort' the PQ HDR EOTF (gamma curve) to attempt to overcome this issue.

https://www.lightillusion.com/uhdtv.html

[SamuriHL]

I think Warner306 hit it on the head when you mentioned that LG does not do a good job at moving between scenes. The impact can be very jarring. The latest firmware fixed a little of that and it's a LOT better than it used to be. They're either reacting too quickly to a brightness change or not quickly enough....I don't know which. But the effect in some scenes pulls you right out of the movie you're watching. That is my one gripe with it. Now maybe that's a symptom of what j82k is talking about with LG going above the PQ curve, I don't really know. I doubt the 2018 owners will see much more improvement now that the 2019 models are coming but we can hope.

[j82k]

I think it's intentional. People often praise the HDR brightness of LG Oleds compared to other manufacturers, even calling sonys dim. I think the reason for that is that LG intentionally made the PQ curve brighter with dynamic tonemapping (which is enabled by default) to stand out when people compare TVs in the showroom and those who display HDR correctly will look dim in comparison. They probably learned that marketing strategy from samsung.

[chros]

https://www.lightillusion.com/uhdtv.html
Thanks, that was really informative! Although I use madVR beta since about 4 months now, I'm still rookie to HDR, e.g. I didn't know:
- absolute vs relative standards (I thought they're all relative)
-- hence viewing environment considarations
-- display device flaws: abl, local dimming
- color gamut volume: 90% of DCI-P3 is basically Rec709

More and more I read about it, I have less intention to replace my current SDR TV. :)

They probably learned that marketing strategy from samsung.
:D

[tp4tissue]

I think it's intentional. People often praise the HDR brightness of LG Oleds compared to other manufacturers, even calling sonys dim. I think the reason for that is that LG intentionally made the PQ curve brighter with dynamic tonemapping (which is enabled by default) to stand out when people compare TVs in the showroom and those who display HDR correctly will look dim in comparison. They probably learned that marketing strategy from samsung.

All the k-brands cheat on their cellphone benchmarks, they've stopped that after being caught..

It's up to madvr enthusaists to put a stop to PQ curve cheating. !! :D

[tp4tissue]

I don't think this is intended, but it could be doing some monkey business with the source, or you need an HDR calibration. Like I said, the newer the model, the better. Panasonic and Sony are known to be better at this.

Is there a way to calibrate through madtpg for use with the HDR tone-mapping function ?

I noticed going through dispcal, the calibration for rec2020 will not slot into the normal calibration page, and only works for the hdr tone-map page.

[Warner306]

A final issue with a lot of displays, specifically home TVs, is the manufacturers deliberately deviating from the HDR specification, in an attempt to generate what they view as 'better' images.

Many home TV manufacturers therefore deliberately 'distort' the PQ HDR EOTF (gamma curve) to attempt to overcome this issue.

https://www.lightillusion.com/uhdtv.html

This is one of the early articles released when HDR was introduced. I think it is less common to artificially brighten HDR content since calibrators have made TV manufacturers more conscious of properly following the PQ curve. Consumers are also becoming more educated about PQ HDR content.

Brightening the PQ curve does come with drawbacks. All HDR video games include a brightness slider to increase the brightness of HDR games. However, this raises the value for reference white, which comes at the expense of making the blacks more grey in dark scenes. The 2017 LG OLEDs suffered from this issue, which was corrected in the 2018 models. I don't know if the 2018 models are doing any other manipulation of the PQ curve, but it doesn't really make sense to have a dynamic tone curve that is constantly fluctuating above and below the PQ curve without distorting the image. Samsung uses a static curve with its QLEDs, but it is either rising from black more slowly or compensating for the brighter 0-100 nits by using more aggressive local dimming. I'm sure even Samsung will do away with this when dynamic tone mapping is added.

You don't really want to brighten images with absolute brightness values because the image can become washed out if pushed too far.

[Warner306]

Is there a way to calibrate through madtpg for use with the HDR tone-mapping function ?

I noticed going through dispcal, the calibration for rec2020 will not slot into the normal calibration page, and only works for the hdr tone-map page.

You can create an SDR 3D LUT if you output in an SDR format. But you can't use a 3D LUT with pixel shader when outputting in an HDR format. You would have to choose to tone map by 3D LUT and make a few static tone curves: 500 nits, 1,000 nits, 1,500 nits and 4,000 nits to replace the display's internal static curves. This could be accomplished with a few profile rules under hdr.

[Plutotype]

Hi folks,
Will madvr support HDR10+ dynamic metadata decode or passthrough?
Thanks

[Alexkral]

Hi folks,
Will madvr support HDR10+ dynamic metadata decode or passthrough?
Thanks

That depends on LAV filters first.

This is one of the early articles released when HDR was introduced.

The problem with HDR being too dark is still there though. 100 nits for diffuse white is too low in not ideal conditions (I'd say it's even too low in ideal conditions but that's just my oppinion) compared to where most people is used to see it in SDR. ITU-R BT.2408-0 recommends diffuse white = 203 nits for PQ and HLG production on a 1000 nits peak luminance display. Another study in the same report suggests diffuse white at 140 nits for indoor scenes and 425 nits for outdoor scenes, for PQ with 4000 nits peak luminance. I think I have read somewhere that at least some titles now are being graded with diffuse white at 203 nits. This should be the best way to solve this. We loose 1 stop at highlights but the overall brightness match better with SDR.

it doesn't really make sense to have a dynamic tone curve that is constantly fluctuating above and below the PQ curve without distorting the image.

If I'm not wrong, both SMPTE ST 2094-10 (Dolby Vision) and SMPTE ST 2094-40 (HDR10+) curves change dynamically the knee point in a similar way that what Soulnight's utility with dynamic target nits is doing now with the BT.2390 EETF.

[tp4tissue]

You can create an SDR 3D LUT if you output in an SDR format. But you can't use a 3D LUT with pixel shader when outputting in an HDR format. You would have to choose to tone map by 3D LUT and make a few static tone curves: 500 nits, 1,000 nits, 1,500 nits and 4,000 nits to replace the display's internal static curves. This could be accomplished with a few profile rules under hdr.

Yea, that's what I meant, create an HDR 3Dlut, but ONTOP of Dynamic Tonemapping, output HDR.

Do you know if this feature will be added in the future ?

Seems to be straightforward, is there a specific hitch that it's not already possible ?

[70MM]

Ive tried error diffusion 1 and 2 for dithering in madvr and I cant see any obvious differance between them. Im upscaling BDs to 4K and displaying on a large 145" curved screen with a JVC NX9 4K projector. Since I dont know which is best as I see nothing, which might be the prefered option in my case producing the less artifacts? Thanks in advance...

[huhn]

the default ordered dithering

[70MM]

the default ordered dithering
Can you explain to me please huhn why ordered dithering is better than error diffusion 1 & 2 please? Thank you kindly for helping...

[SamuriHL]

He's not saying it is. But if you don't SEE a difference, there is a HUGE difference in performance between ordered and error diffusion and there's no sense killing performance for something you can't see.

[70MM]

He's not saying it is. But if you don't SEE a difference, there is a HUGE difference in performance between ordered and error diffusion and there's no sense killing performance for something you can't see. Ok thank you I understand, however that isnt an issue with me anyway as I have the 1080Ti card and using the highest NGU settings upscaling everything to 4K. My rendering hardly ever goes above 20 and I have no dropped or repeated frames for days/ever.

[tp4tissue]

Ok thank you I understand, however that isnt an issue with me anyway as I have the 1080Ti card and using the highest NGU settings upscaling everything to 4K. My rendering hardly ever goes above 20 and I have no dropped or repeated frames for days/ever.

Luma scaler difference is the only thing that's visibly different (At a Distance).

For chroma, dithering, etc, the differences are really only visible if you walk in real close, or zoom in.


The sharpening algorithms are also very visible, but they're taste-based, and not a better or worse situation.


LOOKING FOR a difference is mostly academic, because you simply wouldn't notice much of it while a movie plays.

If knowing it's there helps you sleep at night or justify equipment purchases, then Zoom in, squint real hard, the little hairs on people's faces will look just a tad sharper. :p

[70MM]

thank you for the comments...

[Asmodian]

Can you explain to me please huhn why ordered dithering is better than error diffusion 1 & 2 please? Thank you kindly for helping...

Error diffusion is a tiny bit sharper and more random while ordered dithering has the lowest apparent noise. All three options are very good, I think I prefer ordered dithering on my 55" OLED TV while I like ED 1 or 2 on my LCD monitors, but the differences are also very subtle. Ordered is a great option because it is so high quality while also being fast.

[Warner306]

The problem with HDR being too dark is still there though. 100 nits for diffuse white is too low in not ideal conditions (I'd say it's even too low in ideal conditions but that's just my oppinion) compared to where most people is used to see it in SDR. ITU-R BT.2408-0 recommends diffuse white = 203 nits for PQ and HLG production on a 1000 nits peak luminance display. Another study in the same report suggests diffuse white at 140 nits for indoor scenes and 425 nits for outdoor scenes, for PQ with 4000 nits peak luminance. I think I have read somewhere that at least some titles now are being graded with diffuse white at 203 nits. This should be the best way to solve this. We loose 1 stop at highlights but the overall brightness match better with SDR.

I wouldn't be against raising the value of reference white slightly for PQ HDR content. The problem is all existing HDR displays are tuned to tone map for a reference white of 100 nits, so I don't know how you would get around that without breaking support for all legacy HDR displays. I don't think HDR is too dark when viewed without ambient light in the room.

Displays could at least have a standard brightness slider like video games to make HDR a little brighter during the daytime, even if raised the bottom of the image a little.


If I'm not wrong, both SMPTE ST 2094-10 (Dolby Vision) and SMPTE ST 2094-40 (HDR10+) curves change dynamically the knee point in a similar way that what Soulnight's utility with dynamic target nits is doing now with the BT.2390 EETF.

The knee point just changes where the tone mapping roll-off begins. The curve always slopes to the right away from the PQ curve, so the image never gets brighter; it only gets darker.

Soulnight's tool increases or decreases the target nits. Increasing the target nits raises the knee point further up the PQ curve to reduce compression, but it also changes the absolute brightness of all values relative to the output display. For example, if the display is 100 nits, selecting 200 nits will lead to a loss of more or less half of the calculated brightness of the tone mapped values because the target display is assumed to be twice as bright as the actual output display. The gamma curve is relative, so the output brightness isn't always that precise, but it is close.

When the target nits is higher, the pixel values are more spread out, but they use more of the lower region of the gamma curve to handle the majority of the pixels 0-100 nits. The pixels that represent the highlights are separated to the brightest end of the gamma curve. So the image has more contrast between bright and dark detail and looks less flat because the pixels are less compressed, but the overall image ends up darker.

[tp4tissue]

I wouldn't be against raising the value of reference white slightly for PQ HDR content. The problem is all existing HDR displays are tuned to tone map for a reference white of 100 nits, so I don't know how you would get around that without breaking support for all legacy HDR displays. I don't think HDR is too dark when viewed without ambient light in the room.




I noticed that calibrating to 2.2/2.4 (relative) gamma on LCD is much more similar in appearance to 2.2/2.4 (absolute) gamma (1886) on CRT/Plasma/OLED, vs using absolute gamma (1886) on LCD which makes everything greyish.

So, the near crush dark tones when using relative gamma on LCD is probably Correct. It's just more crush like in home environments where the room light is on.

The moral of the story is, it's suppose to look like that, just turn the lights off.

[SamuriHL]

Shockingly 418.82 didn't break HDR switching. LOL

[tp4tissue]

Weird Gamut behavior.

So on my ATI card, my spare bedroom tv reports a slightly wider Gamut +10% vs my Nvidia Card.

Is it because the Nvidia card is using the alpha channels differently ?

Does madvr use alpha channels in output or only 24bit.

[nevcairiel]

There is no alpha channel on the output. Different results might be up to dithering.

[tp4tissue]

There is no alpha channel on the output. Different results might be up to dithering.

Hrrrm..

I guess that must be the tv's gamut clamping software intervening with the nvidia output.

Is there a fundamental output difference between ATI and Nvidia, some sort of flags ??

Because both these cards are setup for 8bit rgb, yet the ATI results in the +10% , quite large a swing.

[huhn]

nvidia has full support for the HDMI content type so try that. afaik AMD doesn't have an option for that maybe in registry like so many more options.

[tp4tissue]

nvidia has full support for the HDMI content type so try that. afaik AMD doesn't have an option for that maybe in registry like so many more options.

What do you mean by hdmi content type.

I've set both outputs to RGB 32bit 8 bit full based on your previous recommendation ?

[Warner306]

Yea, that's what I meant, create an HDR 3Dlut, but ONTOP of Dynamic Tonemapping, output HDR.

Do you know if this feature will be added in the future ?

Seems to be straightforward, is there a specific hitch that it's not already possible ?

I was going to answer your question earlier but missed it.

It is hard to use a 3D LUT this way because DisplayCAL enforces its own roll-off. I don't know how you would do it without excessive doubling processing. The 3D LUT could maybe correct the white balance and white point, but not alter the transfer function with its own roll-off.

[tp4tissue]

I was going to answer your question earlier but missed it.

It is hard to use a 3D LUT this way because DisplayCAL enforces its own roll-off. I don't know how you would do it without excessive doubling processing. The 3D LUT could maybe correct the white balance and white point, but not alter the transfer function with its own roll-off.

Why does the tone map function only work with an SDR lut ?

For example, on many tvs, in HDR input mode, the Gamut is larger than its SDR mode.

So, after madvr does the tone map, instead of going to an sdr calibrated table before output, it will go to a wider hdr calibrated table.

[el Filou]

What do you mean by hdmi content type.It's an option in HDMI where the source can specify what type of content is sent, e.g. computer graphics/movie/photos/auto.
With NVIDIA you can change that setting in the control panel. Most TVs use a different kind if picture processing depending when that setting is on something other than auto.

[huhn]

how do you stop a TV from dynamic tone mapping in HDR mode.

if you do dynamic tone mapping and send this technically wrong image to the TV the TV will do again dynamic tone mapping making it even more wrong so waht'S the point of an 3D LUT here.

just set your Tv up for native gamut or send bt 2020 so it will use the full gamut.

who even told you there is an wider "calibration table" for HDR?

What do you mean by hdmi content type.
http://abload.de/img/hdmi-content-typebtumj.png

first result in an search engine

[huhn]

It's an option in HDMI where the source can specify what type of content is sent, e.g. computer graphics/movie/photos/auto.
With NVIDIA you can change that setting in the control panel. Most TVs use a different kind if picture processing depending when that setting is on something other than auto.

just so you know i have a PC monitor that is resyncing when it is on auto everytime a video is played and stopped.

so auto means nvidia or other software is able to actively change that.

[tp4tissue]

who even told you there is an wider "calibration table" for HDR?


http://abload.de/img/hdmi-content-typebtumj.png

first result in an search engine


It's not a wider table, but the gamut is wider and different between SDR and HDR modes.

Even in the various different sdr modes, tvs can have different gamuts.



If I set the HDMI content type on AUTO, what is it defaulting to when running madvr (Movie ? or Desktop Program)

[huhn]

no clue.

edit: madVR FSE is triggering "games" with FSE and i can't find anything with windowed mode.
is so advance that leaving it will disabled gaming mode in my TV even if i manually enabled it before.
setting the output type to movies in the GPU driver switches my TV into cinema preset(d80 whitepoint close panasonic close call...) and my TV even shows an notification. i didn't find a program that does trigger this in the GPU driver.

so madVR may trigger gaming mode in the nvidia driver which makes sense if you think about it.

[chros]

edit: madVR FSE is triggering "games" with FSE and i can't find anything with windowed mode.
is so advance that leaving it will disabled gaming mode in my TV even if i manually enabled it before.
setting the output type to movies in the GPU driver switches my TV into cinema preset(d80 whitepoint close panasonic close call...) and my TV even shows an notification. i didn't find a program that does trigger this in the GPU driver.

so madVR may trigger gaming mode in the nvidia driver which makes sense if you think about it.

Interesting finding, thanks, I'll try it out tonight with my old LG TV, maybe ... :)

[Alexkral]

Soulnight's tool increases or decreases the target nits. Increasing the target nits raises the knee point further up the PQ curve to reduce compression, but it also changes the absolute brightness of all values relative to the output display.

Actually what you are changing with the target peak nits parameter is the absolute (only relative to the mastering display luminances) value of the knee point, which affects all the values above it. After that, all the image values need to be normalized to the [0, 1] SDR relative range, which raises the global brightness. That's why I thought that the dynamic curves where doing the same, but after reading in more detail the specs this doesn't seem to be the case. For Dolby Vision the target luminances don't change, but for HDR10+ there is indeed a parameter called TargetedSystemDisplayActualPeakLuminance which is a 2D LUT that affects all values, and is intented to take into account the "peak luminance that a display is capable of delivering while rendering the scene", which "depends on the spatial distribution of the luminance levels of the pixels in the scene and the power consumption limits of the display".

[Warner306]

I have no idea what that means. But the knee point is just the point on the original PQ curve where the tone mapping curve begins. Values above the knee point are rolled-off or reduced in brightness. The shape of the tone curve determines how much values are rolled-off. It isn't really magic. Each luminance value is lower than the original by an increasing amount up to the display peak.

Dolby Vision would just provide formulas for different displays to reduce the overall dynamic range of the source for each scene based on a content flag indicating the peak brightness of the scene. It probably wouldn't be that different than what madVR is already doing. Tone mapping uses pretty standard formulas. It just needs to know how bright the input is in order to compress it.

This is what a 700 nits tone curve might look like: https://i.postimg.cc/4NQWBHtC/PQ-Tone-Mapping-Curve.jpg

There is also an article here on tone curves: https://www.insightmedia.info/should-hdr-displays-follow-the-pq-curve/

[Alexkral]

Ha ha, I read that article yesterday, really.

I don't know what you didn't understand so I can't help, but as you said it isn't really magic. I've written a pixel shader implementing the curve, so I know how it works, and it's not very difficult to at least get an idea of the process by just looking at the maths.

https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2390-5-2018-PDF-E.pdf

It only doesn't include the last scaling step.

[Warner306]

I've seen that. Honestly, to a lay person that article is just nonsense. Tone mapping intelligently compresses luminance. It doesn't do much more than that.

madVR is tone mapping in PQ nits as per BT.2390 to a target display brightness. But this has to be converted to an SDR gamma curve. The gamma curve should always provide an optimum result within its actual target brightness, but it is often better to use the relative gamma curve to spread out BT.2390 (go above the display target brightness) to get more contrast. Changing the target nits kind of makes the PQ curve disappear because the mapped values are no longer 1:1 with BT.2390 in terms of absolute luminance, but it works because the gamma curve increases or decreases overall contrast in a uniform manner.

[tp4tissue]

no clue.

edit: madVR FSE is triggering "games" with FSE and i can't find anything with windowed mode.
is so advance that leaving it will disabled gaming mode in my TV even if i manually enabled it before.
setting the output type to movies in the GPU driver switches my TV into cinema preset(d80 whitepoint close panasonic close call...) and my TV even shows an notification. i didn't find a program that does trigger this in the GPU driver.

so madVR may trigger gaming mode in the nvidia driver which makes sense if you think about it.

How do you find which one it triggers.

My setting box doesn't even have all those options,

I only have Movie, and Desktop Program :scared:

[el Filou]

I also only have those two. Probably depends on what the display advertises, but my TV settings have the same ones listed here (they can be allowed or denied individually for use with the auto mode): https://www.hdmi.org/manufacturer/hdmi_1_4/content_type.aspx

As with all 'automagic' features it can be difficult to find out what changes are applied and when.

[chros]

I only have Movie, and Desktop Program :scared:
It's the same here with my Tv, and the TV doesn't do anything different when I select any of those :) (using windowed mode)

[huhn]

How do you find which one it triggers.

My setting box doesn't even have all those options,

I only have Movie, and Desktop Program :scared:

you manually select all and see what changes in your TV setting.

it only cared about movie and games the rest did do anything at least i couldn't find it.

games option activates gaming mode on my screen.
and movies option switched my preset to cinema.

why photo or graphics doesn't change the preset to the graphic or photos i don't have a clue. if in doubt GPU driver bug.

with auto madVR will activated gaming mode in FSE so it has to be gaming.

[Grimsdyke]

Is the dithering in LAV video decoder the same process as in MadVR ? So could it be set to 'none' there ? Thx

[nevcairiel]

Never turn off any dithering.