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bt.2390 tone mapping blown out whites


PontusN
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Hi!
Just switched from a small NUC as a server to using the emby docker in unRAID. Im using SW tone mapping for some users, the CPU can handle this no problem.

I think the bt.2390 is the best option for color accuracy, but noticed that whites (where HDR peaks above 400nits) is VERY blown out. This does not occur with the other options, but they have other flaws, mostly in color saturation or black levels.
Is this a common issue for those few using SW tone mapping?

@softworkz

ffmpeg-transcode-e2c37e90-841f-45fb-a3b5-df5bc9f54967_1.txt

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On 5/24/2021 at 6:55 PM, PontusN said:

Hi!
Just switched from a small NUC as a server to using the emby docker in unRAID. Im using SW tone mapping for some users, the CPU can handle this no problem.

I think the bt.2390 is the best option for color accuracy, but noticed that whites (where HDR peaks above 400nits) is VERY blown out. This does not occur with the other options, but they have other flaws, mostly in color saturation or black levels.
Is this a common issue for those few using SW tone mapping?

Whether tone-mapping works well depends not only on the algorithms and implementation, but also on whether the required meta-data is correctly included in the videos.
This is especially true for the BT.2390 option. The others provide at least fair results when that metadata is missing, but with BT.2390, you can get pretty bad results in that case.

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On 5/26/2021 at 10:34 AM, softworkz said:

Whether tone-mapping works well depends not only on the algorithms and implementation, but also on whether the required meta-data is correctly included in the videos.
This is especially true for the BT.2390 option. The others provide at least fair results when that metadata is missing, but with BT.2390, you can get pretty bad results in that case.

I'm a noob to this.  Is there a way to definitively tell if that's the case?  Like some data in mediainfo or something?

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8 minutes ago, bozrdnag said:

I'm a noob to this.  Is there a way to definitively tell if that's the case?  Like some data in mediainfo or something?

I did not check with Mediainfo, but after softworkz response I tried with a full Remux instead of the file I tried first, with Vastly better results. So I took that as an answer for myself.

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I'm not asking because I doubt softworx.  I'm asking how I can tell for myself on a given title.  I have a mix of personally ripped and Radarr'd content.  Just wondering if I can tell if maybe I got a bad rip or something?  Do some physical disks lack this metadata some times?

 

For example, I see exactly what you're talking about on Aquaman.  Does that UHD BD just lack the metadata or is my rip somehow faulty?

Edited by bozrdnag
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37 minutes ago, bozrdnag said:

I'm not asking because I doubt softworx.  I'm asking how I can tell for myself on a given title.  I have a mix of personally ripped and Radarr'd content.  Just wondering if I can tell if maybe I got a bad rip or something?  Do some physical disks lack this metadata some times?

 

For example, I see exactly what you're talking about on Aquaman.  Does that UHD BD just lack the metadata or is my rip somehow faulty?

Just checked both my "bad" one and the good remux. Mediainfo states "Transfer characteristics : PQ" (Could say HLG) and "HDR format : SMPTE ST 2086, HDR10 compatible" for both files. So nothing that differs there. The only difference I found was the Remux using main10@L5.1 instead of 5.0. But that should not affect HDR and only things like maximum allowed bitrate.

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2 hours ago, bozrdnag said:

I'm a noob to this.  Is there a way to definitively tell if that's the case?  Like some data in mediainfo or something?

As of now: no. There is static (HDR10) metadata and dynamic metadata (HDR10+, Dolby Vission) and for each case, several variants exist to convey HDR metadata. Not even ffmpeg supports them all, DolbyVision is a work-in-progress, for HDR10+ (Samsung), I'm not sure. The dynamic formats are supposed to be downward compatible to HDR10, but for the static metadata, there are several way as well and also some deviating interpretations of the spec regarding the units of brightness values.

It's kind of a jungle and I have some suspicion that the big players are battling about market dominance. I've read the Dolby Vision spec and I really can't see any reasonable explanation for having so many different subvariants for the very same thing, other than confusing the competition. 

1 hour ago, PontusN said:

"Transfer characteristics : PQ" (Could say HLG)

The perceptive quantizer transfer is used with HDR10, not with HLG.

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8 minutes ago, softworkz said:

The perceptive quantizer transfer is used with HDR10, not with HLG.

I meant that Transfer characteristics has two options, PQ or HLG. I was a bit unclear.

Edited by PontusN
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