HDR heatmaps and torch mode UHDs

[Macatouille]

Originally Posted by Fjodor2000

Just so I understand what you are comparing in those two analyzed screenshots: I assume both are from the 4K BD? I.e. first screenshot(s) from the blown out "flashback" scene, and then the non-blown out one(s) from the Finale?

All of our shots are from the 4K Blu-ray.

Originally Posted by Fjodor2000

To determine that, I guess a similar analysis would have to be made of the same screenshots when taken from the BD instead, so the screenshots from the BD vs 4K BD can be compared. But I don't know if the analysis tools that you are using also are able to handle SDR screenshots from BD, or only HDR screenshots from 4K BD?

I assume you'd need to do proper tone-mapping of the HDR screenshots to compare them to the previous Arrow Blu-ray release (their 4K release doesn't come with that disc). Even then, though, you're only comparing home video releases - you aren't comparing shots from the negative or a print.

And I'm unsure how reliable they are, but Caps-a-holic's already done that:

[dorian]

Originally Posted by Fjodor2000

Just so I understand what you are comparing in those two analyzed screenshots: I assume both are from the 4K BD? I.e. first screenshot(s) from the blown out "flashback" scene, and then the non-blown out one(s) from the Finale?

Because just to clarify, I think nobody disputed that there was a difference between those. The dispute was whether the blown out scenes on the 4K BD were sufficiently blown out. More specifically, if the blown out scenes were even more blown out on the BD.

To determine that, I guess a similar analysis would have to be made of the same screenshots when taken from the BD instead, so the screenshots from the BD vs 4K BD can be compared. But I don't know if the analysis tools that you are using also are able to handle SDR screenshots from BD, or only HDR screenshots from 4K BD?

The tool is for measuring absolute light levels, not arbitrary grading choices. You can arbitrarily clip 90% of the image in the grading tone curve and still have everything in the image measure under 50 nits depending on where you set your peak white.

If you set your peak white at code value 1023, the maximum light level would measure 10,000 nits whereas at code value 520 it would only measure 100 nits.

More of the image is clipped on the blu-ray but whether or not the UHD is sufficiently clipped to serve the story remains a matter of opinion.

[Fjodor2000]

Originally Posted by dorian

The tool is for measuring absolute light levels, not arbitrary grading choices. You can arbitrarily clip 90% of the image in the grading tone curve and still have everything in the image measure under 50 nits depending on where you set your peak white.

If you set your peak white at code value 1023, the maximum light level would measure 10,000 nits whereas at code value 520 it would only measure 100 nits.

More of the image is clipped on the blu-ray but whether or not the UHD is sufficiently clipped to serve the story remains a matter of opinion.

Yes, I guess it depends on what is considered the reference w.r.t. grading in this case.

But if one compares the BD vs 4K BD on caps-a-holic that Macatouille referred to, the difference is quite striking:

https://caps-a-holic.com/c.php?go=1&...189778&i=6&l=0

Switching back and forth between the two versions there at least makes it quite clear that the BD is far more blown out than the 4K BD in the "flashback" scenes.

Not sure if anyone remembers what it originally looked like when shown in the theaters, and if that was closer to the BD or 4K BD in this regard?

[Macatouille]

Originally Posted by Fjodor2000

Not sure if anyone remembers what it originally looked like when shown in the theaters, and if that was closer to the BD or 4K BD in this regard?

Honestly, I wouldn't trust anyone who says they remember how this 28 year old movie originally looked in theaters.

[Macatouille]

Akira (1998)

Mastering display luminance              : min: 0.0050 cd/m2, max: 1000 cd/m2
Maximum Content Light Level              : 1000 cd/m2
Maximum Frame-Average Light Level        : 369 cd/m2

Heatmaps

[Show spoiler]

Gamut Visualizations

[Show spoiler]

HDR10 Plot

[sojrner]

Originally Posted by Macatouille

Akira (1998)

Is this the replacement disk that (supposedly) added HDR, or the original disk that mistakenly had no HDR? (b/c, um... it looks like the original, right?)

[LoSouL]

SDR Heatmaps would be a great thread.

[Macatouille]

Originally Posted by sojrner

Is this the replacement disk that (supposedly) added HDR, or the original disk that mistakenly had no HDR? (b/c, um... it looks like the original, right?)

Disc definitely has HDR. It shows up in MediaInfo and I get the pop-up on my TV when I play it. Did that defective disc actually have HDR and it just wasn’t implemented right? Or was it true SDR?

[dorian]

Originally Posted by LoSouL

SDR Heatmaps would be a great thread.

SDR heatmaps will only lead to confusion IMO. Gamma based transfer functions are relative so the results will vary greatly depending on how bright your TV is set up.

If people genuinely want them, I can create a similar script for gamma encoded content with a nominal 100 nit peak.

[LoSouL]

Originally Posted by dorian

SDR heatmaps will only lead to confusion IMO. Gamma based transfer functions are relative so the results will vary greatly depending on how bright your TV is set up.

If people genuinely want them, I can create a similar script for gamma encoded content with a nominal 100 nit peak.

I was just joking, but if the thread is entertaining or has any interesting information, I'd frequent it.

[sojrner]

Originally Posted by Macatouille

Disc definitely has HDR. It shows up in MediaInfo and I get the pop-up on my TV when I play it. Did that defective disc actually have HDR and it just wasn’t implemented right? Or was it true SDR?

Nah, when it was first released, the disc was incorrectly SDR. They sent out replacements. I just didn't know what release has what version. I don't remember if the SDR showed HDR metadata or not. Now I gotta go compare the two, as that was long ago. lol

[Macatouille]

Originally Posted by sojrner

Nah, when it was first released, the disc was incorrectly SDR. They sent out replacements. I just didn't know what release has what version. I don't remember if the SDR showed HDR metadata or not. Now I gotta go compare the two, as that was long ago. lol

Here's a snippet from MediaInfo:

Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L5.1@High
HDR format                               : SMPTE ST 2086, HDR10 compatible
Codec ID                                 : 36
Duration                                 : 2 h 4 min
Bit rate                                 : 60.3 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 24.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0 (Type 2)
Bit depth                                : 10 bits
Stream size                              : 52.4 GiB
Writing library                          : ATEME Titan File 3.9.6 (4.9.6.2)        
Color range                              : Limited
Color primaries                          : BT.2020
Transfer characteristics                 : PQ
Matrix coefficients                      : BT.2020 non-constant
Mastering display color primaries        : BT.2020
Mastering display luminance              : min: 0.0050 cd/m2, max: 1000 cd/m2
Maximum Content Light Level              : 1000 cd/m2
Maximum Frame-Average Light Level        : 369 cd/m2

[Geoff D]

Originally Posted by sojrner

Nah, when it was first released, the disc was incorrectly SDR. They sent out replacements. I just didn't know what release has what version. I don't remember if the SDR showed HDR metadata or not. Now I gotta go compare the two, as that was long ago. lol

The original release was 'proper' 10-bit SDR 709, it wasn't some wonky HDR encode missing a flag or something.

[Cactus]

Spaceballs (1997).

Not sure I'm doing this right, but here goes:
Original screengrabs saved as PNG from AVIDemux.

[Show spoiler]

[Labor_Unit001]

Originally Posted by Macatouille

Akira (1998)

Thanks for the caps. Could you also check out the explosion from right before the title screen?

[Macatouille]

Originally Posted by Labor_Unit001

Thanks for the caps. Could you also check out the explosion from right before the title screen?

Here's a few, showing the explosion growing:

[Show spoiler]

[mrtickleuk]

Originally Posted by dorian

SDR heatmaps will only lead to confusion IMO. Gamma based transfer functions are relative so the results will vary greatly depending on how bright your TV is set up.

If people genuinely want them, I can create a similar script for gamma encoded content with a nominal 100 nit peak.

Yes, I'd be interested in seeing the results - but of course, we should strictly use a 100 nit peak to be meaningful, and 2.4 gamma unless it's very old content.

[dorian]

Avatar: The Way of Water (2022)

[Show spoiler]

[Fjodor2000]

So MaxCLL at 284.5 nits in those screenshots. I would have expected some more HDR pop (ugh) for a modern super high budget blockbuster movie.

[dorian]

Originally Posted by Fjodor2000

So MaxCLL at 284.5 nits in those screenshots. I would have expected some more HDR pop (ugh) for a modern super high budget blockbuster movie.

Of the 200 screenshots I took, very few exceeded 250 nits with none of them exceeding 300 nits. Modern super high budget blockbuster movies don't need blazing highlights to look good