madVR - high quality video renderer (GPU assisted)

[Alexkral]

Originally Posted by Warner306

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...-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/op...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]

Originally Posted by 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.

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

[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/hd...tent_type.aspx

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

[chros]

Originally Posted by tp4tissue

I only have Movie, and Desktop Program

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]

Originally Posted by tp4tissue

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

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.

[sneaker_ger]

Originally Posted by Grimsdyke

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

LAV only dithers when it has to convert the output format. If you use madvr and don't deactivate any of the default output formats in LAV Video this basically never happens. Like nevcairiel said: never turn off dithering in madvr. It's necessary as madvr does all kinds of processing (like chroma upscaling) in high bitdepth.

[sat4all]

@Manni

Would you please check if 418.81 passthrough still sends bogus metadata?

Edit: You have already answered that in another thread, Thanks!

[70MM]

Originally Posted by sneaker_ger

LAV only dithers when it has to convert the output format. If you use madvr and don't deactivate any of the default output formats in LAV Video this basically never happens. Like nevcairiel said: never turn off dithering in madvr. It's necessary as madvr does all kinds of processing (like chroma upscaling) in high bitdepth.

Sorry guys I dont understand this staement. I use madvr with JRiver. I use dithering in madvr, have done for years. But Ive never gone into Lav Filters and and deactivated any default output formats as I wouldnt even know how to get in there or even do anything.... Am I doing something wrong here, is my dithering in madvr actually working or not?

[sneaker_ger]

You are doing everything correctly.

[nevcairiel]

Most people should probably never touch any of the dithering settings, and they would get an optimal experience that way even.

[tp4tissue]

Originally Posted by nevcairiel

Most people should probably never touch any of the dithering settings, and they would get an optimal experience that way even.

Just chking, the RGB output lvl in _Lav Filter_ should be sett to 255 right ?

I've always wondered, because it always looks the same on output, so I just assumed madvr was doing everything ?.

[huhn]

it needs very specific to ever do anything and that'S not going to happen with madVR.

it's called RGB output levels (for YUV-> RGB conversation)
so where are you outputting YUV as RGB?

[tp4tissue]

Originally Posted by huhn

it needs very specific to ever do anything and that'S not going to happen with madVR.

it's called RGB output levels (for YUV-> RGB conversation)
so where are you outputting YUV as RGB?

I assumed the lav feeds into madvr, so then madvr takes that and does magic ?

[70MM]

I have the new JVC NX9 projector and want to try using the pixel shader tone mapping in madvr rather than the auto tone mapping in my NX9. However since Im new to this and dont understand, what "target peak nits" setting should I use on madvr for my NX9 projector? Thank you in advance...

[SamuriHL]

Looks like that projector is somewhere around 185 nits max. I could be off so hopefully someone else chimes in that knows what they're talking about (hint not me! LOL)