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[umberto5585]

Hello all,
There have been great improvements to the jrvr tonemapping however there is one thing ive noticed that Im curious if anyone else has a fix for.  On certain scenes, Ive observed that bright areas of a scene are sometimes blown out temporarily and appear to fill in detail gradually. 

The best example I can provide is the very first shot of 1917 which fades onto an open field before showing the main characters. No matter what settings  I apply (at 100 nits) you can see the mountains blow out into white light before gradually re-appearing.  Is this a result of too aggressive settings, or knee adaptation etc? I try the same scene with Madvr and this blowout does not occur.

Most content looks fantastic after the updates but im wondering if perhaps others can confirm this scene and/or suggest a fix.  Thanks in advance for any suggestions!!

[JimH]

What is your full version of MC?

[umberto5585]

Currently on 32.0.58 64bit version... thanks for the reply.  If anyone has the same version and can find a moment to test. 1917 is a big one for us home theater guys  .  The timestamp is 1:00-1:10. Literal first shot after the opening titles where you can see the bright scenery in background dissapear and re-appear rather subtle. Trying to figure out what setting can modify or lessen this or if my various settings are too aggressive etc. Thanks in advance!

[mattkhan]

I'd say jrvr tonemapping does tend towards blowing out the highlights relative to madvr but it really depends exactly how you configure both of them (particularly madvr which has a million knobs to tweak)

[umberto5585]

Sooo in this case.. any recommendations on what settings to tweak?? Haven't seen this come up on the thread but its a noticeable issue. I thought I should put the issue in the jrvr tonemapping discussion here but couldnt locate it. Perhaps it can be addressed in an update or something.

[mattkhan]

There's some discussion in the jrvr thread iirc, you should post pictures showing a comparison along with your settings though then we can see what you are talking about

[umberto5585]

Sure thing...I have attached some pics below and labeled them as best as I can.. First pic demonstrating the blown out hills in the scene from 1917 which then fade in.  80 nits settings for testing, and gradually the background detail emerges in the second pic.  The same scene playing in MadVR at 80 nits, where this detail is not blown out for some reason. Note the difference in the sky detail and hills.  I also attached images of some of the settings.  Let me know if this is helpful.  I appreciate it!!

[mattkhan]

good find

there's definitely a momentary brighten adaptation in the background in that scene for me with jrvr, it lasts a v short period of time (sub second) but is not present with madvr. I would expect that is related to the brighten adaptation algorithm but couldn't be sure of that. Does it last longer for you or it's similarly a brief white out and then back to normal?

I'm not sure if mine is as severe as yours or I'm just watching it in motion vs a screen cap, perhaps you can share a precise timestamp for that one?

if it is what I think it is, I don't think this is fixable by tweaking and it would be one for Hendrik to take a look at.

[Hendrik]

There is always a balance between instant adaption to scene changes, and potential issues with flashing. Probably just going to accept this as is.

[mattkhan]

@Hendrik can you (re)confirm what the "lively" preset is in terms of the parameters we can tweak? I suspect it's the same as the params I suggested a while back but just wanted to check

[umberto5585]

good find

there's definitely a momentary brighten adaptation in the background in that scene for me with jrvr, it lasts a v short period of time (sub second) but is not present with madvr. I would expect that is related to the brighten adaptation algorithm but couldn't be sure of that. Does it last longer for you or it's similarly a brief white out and then back to normal?

I'm not sure if mine is as severe as yours or I'm just watching it in motion vs a screen cap, perhaps you can share a precise timestamp for that one?

if it is what I think it is, I don't think this is fixable by tweaking and it would be one for Hendrik to take a look at.

Indeed its nothing major and I am more than pleased with JRVR's tonemapping.  Its given new life to my media as a projector owner (no JVC with built in tonemapping but rather an epson 5050ub).  But yes, it is rather brief and appears to happen from 1:03-1:05 lasting maybe a couple seconds if that.  I did also tweak various "custom" settings in Spline, and tried the other algorithms including Hable to no avail.  Its a unique example, but again more a rarity that stands out as intriguing on one of my favorite films. Probably would not have even caught it otherwise.   I appreciate you all taking time to respond.

[murray]

Sure thing...I have attached some pics below and labeled them as best as I can.. First pic demonstrating the blown out hills in the scene from 1917 which then fade in.  80 nits settings for testing, and gradually the background detail emerges in the second pic.  The same scene playing in MadVR at 80 nits, where this detail is not blown out for some reason. Note the difference in the sky detail and hills.  I also attached images of some of the settings.  Let me know if this is helpful.  I appreciate it!!

I thought "Blue Noise" was better than "Ordered Dithering"?

[umberto5585]

I thought "Blue Noise" was better than "Ordered Dithering"?

Yeah. I think it is, but ive tried both and its completely irrelevant and inconsequential to the brightness adaptation issue being discussed here. Just happened to be on those settings here. Thanks tho.

[murray]

Yeah. I think it is, but ive tried both and its completely irrelevant and inconsequential to the brightness adaptation issue being discussed here. Just happened to be on those settings here. Thanks tho.

Just going to test 1917 for you, I know it well.

[murray]

Sure thing...I have attached some pics below and labeled them as best as I can.. First pic demonstrating the blown out hills in the scene from 1917 which then fade in.  80 nits settings for testing, and gradually the background detail emerges in the second pic.  The same scene playing in MadVR at 80 nits, where this detail is not blown out for some reason. Note the difference in the sky detail and hills.  I also attached images of some of the settings.  Let me know if this is helpful.  I appreciate it!!

Im not sure why your HDR doesnt show this like mine does?

[murray]

Indeed its nothing major and I am more than pleased with JRVR's tonemapping.  Its given new life to my media as a projector owner (no JVC with built in tonemapping but rather an epson 5050ub).  But yes, it is rather brief and appears to happen from 1:03-1:05 lasting maybe a couple seconds if that.  I did also tweak various "custom" settings in Spline, and tried the other algorithms including Hable to no avail.  Its a unique example, but again more a rarity that stands out as intriguing on one of my favorite films. Probably would not have even caught it otherwise.   I appreciate you all taking time to respond.

OK I just tested 1917, the mountains are there in mine right from the very first fade in, not sure why others dont see this. Im using the JVC NZ9 on a 145" curved ST 130 G4 microperf screen. HDR to SDR.

[mattkhan]

OK I just tested 1917, the mountains are there in mine right from the very first fade in, not sure why others dont see this. Im using the JVC NZ9 on a 145" curved ST 130 G4 microperf screen. HDR to SDR.

We can see them, we are talking about a momentary whiteout after they first appear, lasts under half a second

[murray]

We can see them, we are talking about a momentary whiteout after they first appear, lasts under half a second

I dont have that at all.

[mattkhan]

I dont have that at all.

I would expect it to vary with configured peak nits, I run with 100 and the OP has 80. Perhaps 130 is sufficient to avoid the problem in this case.

[mattkhan]

Im not sure why your HDR doesnt show this like mine does?

If his screen/connection is not HDR capable then it won't show, this is sdr anyway so doesn't matter

[murray]

I would expect it to vary with configured peak nits, I run with 100 and the OP has 80. Perhaps 130 is sufficient to avoid the problem in this case.

Maybe I have no idea, its perfect on mine and the mountains are there right from the start just as there are also in my 1080 copy.

[mattkhan]

Maybe I have no idea, its perfect on mine and the mountains are there right from the start just as there are also in my 1080 copy.

If you want to experiment, try reducing the peak nits and see if you start to see a similar effect

[umberto5585]

Interesting.. I just did the experimenting you suggested.  130 nits does seem to avoid the white-out.  It seems at 100nits is where the effect is more pronounced.  Even 110 nits avoids the effect for the most part so maybe that's the sweet spot to avoid this with other movies although the added pop is preferred on a projector.  I guess the main question is why is MadVR not having that same brightness adaptation struggle at the same target nits? I understand "accept as is" but thats not really a satisfying solution imo.

[mattkhan]

Madvr doesn't have the same problem because it has a different set of algorithms. You can look through https://yabb.jriver.com/interact/index.php?topic=136378.150 for info on how this algorithm is implemented, if you play with the demo on desmos then you can get a feel for how it compresses at different required degrees of compression. Ultimately this sort of issue is content dependent so there is no single number that is going to work (other than having sufficient brightness to not have to compress much)

[murray]

why dont I see much difference in brightness when I change target peek nits?

Also I have many double versions of films, e.g. one print BD 1080 and the same film in HDR. I can never get the HDR version to the same brightness as the SDR version, what am I doing wrong???

[mattkhan]

why dont I see much difference in brightness when I change target peek nits?

what change do you make?

the scene is not v bright though, reported peak is ~150nits I think so there's not that much to do from a tonemapping point of view.

[umberto5585]

Well after watching more films, Im noticing the bright areas blowout/taking a while to fill in the detail issue present on more content. Typically in backgrounds of scenes. I get that it was called a brightness adaptation issue but the same examples arent producing such issues on MadVR or my Zidoo hdr to sdr tonemapping using the Dolby vs10 engine?  Maybe this can be revisited with more discussion or a fix on an update? These instances I again demo on MadVR and see the issue is not present with the same or even lower nits.  Shouldn't really have "leave as is oh well" for the final, definitive answer if its not an issue elsewhere I think? Im a little conflicted on it. Not a huge thing, and the JRVR tonemapping is stunning but again its something not showing up elsewhere in examples. More discussion to revisit this for a future fix is welcome. Thanks