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[jmone]

Thanks - that is what I was doing then started 2nd guessing.  Is it worth greying out such options that don't apply at some point for clarity?

[Hendrik]

There is no way to really know if your screen is actually going to be in HDR mode and HDR output is active, which is why the SDR options don't vanish.

Or you might just be playing a SDR video.

[mattkhan]

seems sensible to disable the screen gamut option in the case when a 3dlut is present if that is unused

in my case then it converts BT2020 input to DCI-P3 (which should have minimal impact given there is not that much content outside P3) and then feeds that through the LUT, right?

[jmone]

Thanks, final question then (I hope).  Is if you are in SDR mode (on the HDR Tab), what is the difference between DCI-P3-D65 and DCI-P3-D65 (in 2020) in the Screen Gamut (Calibration Tab).  I get the latter, just not the former as I would have thought most displays are expecting either 709 or 2020, so limiting to P3 in 2020 makes sense, but are there displays that actually accept native P3?

[mattkhan]

JVC projectors have such a mode

[haasn]

Okay, I've been cooking up a series of improvements to the gamut/tone mapping algorithm:

• Linearly desaturate colors when greatly reducing brightness
• Remove the "chroma margin" as a result, leading to much more accurate gamut mapping for images with high dynamic range
• Nuke the LMS hybrid mixing completely (though I may re-introduce it with a low strength like 0.05)
• Make the perceptual hue shifting much stronger (starting at 70% of the color space's saturation range) to reduce the prevalence of weird hue discontinuities

Latest sample attached, this is with default settings (targetting BT.709 SDR). I think it's a massive improvement, just eyeballing it. Scope is still a bit funny, but then the scope will always be funny because we're doing perceptual / highly non-linear gamut mapping.

[haasn]

Okay, I've been cooking up a series of improvements to the gamut/tone mapping algorithm:

• Linearly desaturate colors when greatly reducing brightness
• Remove the "chroma margin" as a result, leading to much more accurate gamut mapping for images with high dynamic range
• Nuke the LMS hybrid mixing completely (though I may re-introduce it with a low strength like 0.05)
• Make the perceptual hue shifting much stronger (starting at 70% of the color space's saturation range) to reduce the prevalence of weird hue discontinuities

Latest sample attached, this is with default settings (targetting BT.709 SDR). I think it's a massive improvement, just eyeballing it. Scope is still a bit funny, but then the scope will always be funny because we're doing perceptual / highly non-linear gamut mapping.

Throwing this branch at a round of test stills I noticed it regresses the Mad Max lightning sample. Upon further investigation, I found that clipping inside the 3DLUT in IPT space (similar to how relative colorimetric clipping works) before applying the perceptual tone-mapper solves that problem, and also re-introduces some of the subjective "shift towards white" that was always part of the "intended look".

Makes HSV sweep look like this, for better or worse. I think I'm done for now. Will push this round of changes to libplacebo master very soon, then hopefully JRVR can get it soon.

[jmone]

Sounds good & thanks for all the work in such a short period of time.  FWIW - here are the scopes for "HSV Latest" and "HSV Clipping".  They do look cleaner than at the start of this thread, and while still funky on the scope the proof in the pudding will be on real content.

[Hendrik]

Visually, the result looks a lot more pleasing to me, in any case. The perceptual gamut mapping libplacebo does will never produce perfectly shaped vectorscopes, so the goal so far was to remove spikes and other odd shapes with increased precision, and work on the visual result.

I'll be updating MC with a new version of libplacebo this week, and also add a few new options that might help low-brightness/low-contrast cases like projectors, as setting the nits below the reference value is not really recommended. Not sure yet what I should do with that option at all, maybe shrink it and properly explain that it's not the same as madVR's setting.

[haasn]

I'll be updating MC with a new version of libplacebo this week, and also add a few new options that might help low-brightness/low-contrast cases like projectors, as setting the nits below the reference value is not really recommended. Not sure yet what I should do with that option at all, maybe shrink it and properly explain that it's not the same as madVR's setting.

FWIW, with latest libplacebo I think setting target-peak low is actually fine, and definitely good for projectors. See https://github.com/haasn/libplacebo/issues/175

[Hendrik]

Ok, I'll leave the option then. Many moving parts this week!

[jmone]

... the Mad Max lightning sample.

I do like your single frame dump method BTW:

Code: [Select]

ffmpeg -ss HH:MM:SS -i FILE -vframes 1 -vcodec copy -an dump.mkv
For consistency of testing, is there a "collection" of a few of these video samples we can download?

[haasn]

I do like your single frame dump method BTW:

Code: [Select]

ffmpeg -ss HH:MM:SS -i FILE -vframes 1 -vcodec copy -an dump.mkv
For consistency of testing, is there a "collection" of a few of these video samples we can download?

I have some here:

• random single frame samples that I personally use
• madVR test set

[Hendrik]

The next MC build incorporates all the recent libplacebo changes into JRVR.

I've also added some new options:

Output -> Contrast Recovery Strength, lets you tune the strength of contrast recovery. Higher values will have a bigger effect, but can lead to ringing.
Output -> Advanced HDR Settings -> Spline Contrast, lets you define the contrast of the spline tone mapping curve, which allows tuning the image for low contrast/brightness setups in particular, eg. projectors (need to specifically select Spline as the tone mapping curve for this to be available)
Advanced -> Use Tricubic Interpolation for gamut mapping, improved quality, but quite a bit slower.

[jmone]

Thanks Gents!

[jmone]

haasn, thanks for that test set.  Used them with the latest (still in beta) JRVR.  I do like the HFR Gemini Man movie, and with the clip, the results look terrific.  Good Skin Tones, nice saturation and nothing clipping!

[jmone]

The Max Mad Fury Road sample however is not so good (lots of clipping).  Hendrik tells me that this is weirdly mastered with lots of out of Gamut colours, but it really does look poor.  I've also attached how Resolve handles it as a comparison.

[Hendrik]

It doesn't look quite that red to me. Since MC can't open single frame HEVC files, maybe something went wrong when you modified it?

[jmone]

Nope - just played it and hit pause straight away.  Works with all of haasn's clips.  To double check, just played my full copy and looks equally weird which is why I'm wondering if it is a setup issue??

[jmone]

Did a test by also turning off my 709 ICM profile in case that was it, and playing from the original UHD.  Nope - same thing

[Smack]

Thanks Hendrik and all the others for the hard work. Gets better every new release. I love it. I don’t use madvr any more.

[murray]

Im also very pleased, I just dont want to go back to madvr PC!

[haasn]

The Max Mad Fury Road sample however is not so good (lots of clipping).  Hendrik tells me that this is weirdly mastered with lots of out of Gamut colours, but it really does look poor.  I've also attached how Resolve handles it as a comparison.

The Resolve sample looks very undersaturated, are you sure it was correctly tagged as BT.2020? It almost looks like the clip was either bypassing color management or mistagged. That aside, where do you see clipping?

Concerning flames, it's an endless back-and-forth and question of tradeoffs regarding the question of whether or not turning red flames into orange is a desirable property, because the necessary mechanisms to accomplish that inevitably also shift hues of other things. The problem here is that the explosion is, in the HDR source, originally red. It's only through hollywood that we've become accustomed to seeing explosions as orange.

[jmone]

Yup, the resolve one looks undersaturated in general, but if we look at the main body of the explosion, Resolve has a range of hues from red to yellow while the JRVR is Red to pink in the main part of the explosion.  I think the issue is that on the JRVR example the Red in the main part of the explosion has been hard clipped at around 81% (see the Waveform), whereas the Resolve one does not hard clip the red at all so we get different hues.  As a comparison both samples look very similar in their hue for the fire trail that goes to the right, and neither is clipping.  I've never seen a pink fire. 

[jmone]

As a counter point.  I know that many find this shot hard but it is great in JRVR.  It's very saturated, uses all the dynamic range, does not have the hard clipping and just looks terrific to me! 

EDIT: I had to scale this one down a bit as it exceeded the post size limit.

[jmone]

Double checked with a colour picker.  All the "pink" areas correspond to where the red is clipped.

Here is a screen capture as I move the picker around --> https://1drv.ms/v/s!AkiTPpgNxBQVg4hb8jHZ6miUa8NJCA?e=wxVl2E

EDIT: and there is plenty of range above 81%

[tixi]

Hello,

For my Sony projector , SDR->60 nits measured with my Xrite Display Pro ( laser at 60% )  , it's better to use HDR-SDR tonemapping ou HDR-HDR Tonemapping ?
Thanks

[armyplace]

Hello,

For my Sony projector , SDR->60 nits measured with my Xrite Display Pro ( laser at 60% )  , it's better to use HDR-SDR tonemapping ou HDR-HDR Tonemapping ?
Thanks

Try both and see which one is more pleasing to your eyes. I would say MC31 does a better job of tonemapping than the Sony.

[mattkhan]

No Sony projector has dynamic tone mapping so use SDR output

[Smack]

Any recommendations for a low light pj with the new features available?
I’m using an laser epson Ls10000 which is calibrated to dci-p95. At the moment I use 70 as  target nit.

I’m talking especially about these features.

8. NEW: Added new options to JRVR for controlling tone mapping. Output -> Contrast Recovery Strength, Output -> Spline Contrast (advanced HDR settings), Advanced -> Use Tricubic interpolation for gamut mapping.

What are the best settings for my setup?

[karmat63]

I'd add:
is conceptually correct to use the real target nits, as in MadVR? Visually is OK...
The renderer now looks very good, with better contrast and saturation vs MadVR, but, have to say, a bit of red push (clipping), is still there (IMHO)...

[jmone]

Everyone's environment is going to be unique. Projector NITS, Screen Size, Screen Gain, Room Treatment, Ambiant Light etc.  So we all will need to dial it in for what looks good.  Also I'd suggest just dialing in a quick setup at present as there is a heap of refinement of the code going on at present.... so expect continual improvement!  Good times!

[MidnightWatcher]

What about presets for some display devices? Eg: Projectors (Low 50-80 nits/ Medium 80-110 nits / High 110-150 nits / Custom)?

[Hendrik]

With as many variables in play, a preset would largely be quite similar to you just changing the brightness slider to match your setup.

[MidnightWatcher]

I don't understand this answer. Increasing brightness also elevates the black floor. Tuning to accommodate your display's nits would not.

[Hendrik]

haasn asked me to post a test version using some brand new changes in gamut mapping. For faster turn-around, you just get the replacement libplacebo DLLs, for windows 64-bit

https://files.jriver-cdn.com/mediacenter/test/jrvr/libplacebo-290-linear_perceptual.zip

On top of MC 31.0.27 or newer, make sure to play a video first so everything is working, then navigate to "%appdata%\J River\Media Center 31\Plugins\libplacebo64" (you can paste that into explorer, without the quotes), and unzip the plugin in that directory, replacing the files in there (with the same names).

These are the changes from MR 490 on the libplacebo project website:
https://code.videolan.org/videolan/libplacebo/-/merge_requests/490

The changes simplify perceptual gamut mapping, and help solve issues with distorted hue.

Any feedback and testing is appreciated! As always we're looking for feedback on improvements, but also regressions, in comparison to 31.0.27/29.

[jmone]

Nice!  The pink in MM is gone   Using all the dynamic range without the hard clip, very saturated.  Looks good.

[jmone]

Samsung Wonderland Rock gets a step up as well.  The Pink Tint on the white house walls is even further reduced and I don't see any clipping.  As before, very saturated using all the range.  Looks great to my eyes (note: this one is 203nits, and the rest on "Default" settings" - The MM one was at 160nits and Spline as I forgot to reset to defaults for testing).  I also had to scale this one down a bit as it was above the post limit size.

[jmone]

Gemini Man is still looking good!

[jmone]

Wow - handles this scene really really well.  No loss of details in the highlights or the tones on the horses.  Nice!

[jmone]

Also not seeing and "red push" on skin tones.

[mattkhan]

What's your output/screen config?

[jmone]

Another skin tone. 

[jmone]

What's your output/screen config?

For this testing all the screen shots (bar the MadMax one) is set to what I think are the defaults of:
- Target Peak Nits : 203
- Enable Contrast Recovery when tone mapping @ 0.4
- Tone Mapping Alog : Auto-select
- Screen Gamut : Auto
- Gamma Processing : Disabled
- Calibration Method : Disabled

Are these the settings you are after?  I've also not tried to find the "best" settings at this stage, just looking for stuff that looks "wrong".  So far nothing as popped up to complain about!

[mattkhan]

I think the 2 main variables are nits (say 75 for a pj) and gamut (either DCI-P3 or bt2020 Vs rec709)

[jmone]

So my summary on the test clips, is a big "Thanks for a job well done" over the weekend on this.  It is a big improvement on extreme clips without breaking anthing more "normal".  In particular I think it addresses:
- Red Push (on faces)
- Pink Hues in Explosions (though my personal preference is still for a bit more to the yellow for higher nits tone - but that is just an observation)
- Pink Hues when next to red on the walls of those houses (there is still some but you really have to zoom in and it's only on certain walls). 
- Good Skin tones (if anything may be a bit cool but again, no big issue)
- Great jobs on saturation and dynamic range without hard clipping highlights or shadows (horses in the snow, red rock)

Very pleased.  I'll need to move off testing at a generic 203nits/709 and look at what settings works well for my:
- High Nit Flatscreens (OLED, and HDR1000 screens): maybe HDR to HDR tonemapping @ 700/1,000nits and P3in2020, as well as
- My JVC x7500: maybe HDR to SDR tonemapping @ 100 nits and P3in2020

.... but out of the box it is a great image.

Thanks again for all your work,
Nathan

[jmone]

I think the 2 main variables are nits (say 75 for a pj) and gamut (either DCI-P3 or bt2020 Vs rec709)

FWIW - had a quick look at the MM clip set still set to HDR to SDR tonemapping @ 80Nits then with various Screen Gamut Settings.  The Screen Gamut choices of 709 / 2020 / P3-D65 / PD-D65 in 2020 all make a sigfificant difference.  This shot is P3-D65 in 2020.  I can see in the scopes that the Reds are clipping, but I actually prefer this look as it is more yellow in the high nits part of the explosion (but each to their own).  Anyway, it will take some time to run through all of this on various setups. 

I wish there was a way of taking HDR Screen Shots reliably! 

EDIT - Did a test and staight P3-D65 is the closest to the original HDR for me.  My ICC Profile is closer again however.

[jmone]

I wish there was a way of taking HDR Screen Shots reliably!

Well there is (at least on Win11).  Win+Alt+PrtScn will save a PNG and an JXR (JPEG Extended Range) into your C:\Users\[username]\Videos\Captures folder.  The PNG looks to be an SDR tonemapped version, and the JXR is a full HDR screenshot.  Both are way to big too post on this forum, but for those interested here is a link to a screenshot of the Red Rock, with JRVR and Gamut Mapping - https://1drv.ms/u/s!AkiTPpgNxBQVg4hdUfynB_vH9jDN9g?e=OykdCA

No support for JXR in Resolve so I can not peak at scopes.

[jmone]

Concerning flames, it's an endless back-and-forth and question of tradeoffs regarding the question of whether or not turning red flames into orange is a desirable property, because the necessary mechanisms to accomplish that inevitably also shift hues of other things. The problem here is that the explosion is, in the HDR source, originally red. It's only through hollywood that we've become accustomed to seeing explosions as orange.

You are right.  I've just started testing the HDR to HDR Tone and Gamut Mapping, and the MM Clip is absolutely all red hues.  Not Pink.  Not Yellow.  I take back my comments about preferring the Yellow!

[Hendrik]

Here is another (final) test build which fixed some hue shifts around very bright elements, eg. sunlit clouds, etc, by re-introducing some stronger desaturation again.

It might have a small impact on other scenes, so any re-tests are appreciated. But as of right now this is a very significant improvement over the version currently shipping in 31.0.29

New version:
https://files.jriver-cdn.com/mediacenter/test/jrvr/libplacebo-290-gamut2.zip

Refer to the previous post for instructions and additional details:
https://yabb.jriver.com/interact/index.php/topic,136378.msg945282.html#msg945282