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Old 11th November 2022, 15:35   #361  |  Link
FranceBB
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Well, I sent you a present, William.
It's my Christmas gift.


Last edited by FranceBB; 11th November 2022 at 16:04.
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Old 12th December 2022, 14:34   #362  |  Link
Balling
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Quote:
Originally Posted by frank View Post
OK.
My "reference environment" is the living room and tv, not a dark basement. I think 90% of viewers don't sit in the dark to watch a movie on tv. UHD publishers don't get it.
That's why I convert to HLG.
And 200nits look better on my notebook too.
I do. Many people do, cause why BT.709 was for a dark room, end to end gamma 1.2.

While sRGB was for office environement.
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Old 13th December 2022, 00:26   #363  |  Link
kolak
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Quote:
Originally Posted by frank View Post
OK.
My "reference environment" is the living room and tv, not a dark basement. I think 90% of viewers don't sit in the dark to watch a movie on tv. UHD publishers don't get it.
Maybe Dolby did:
https://professionalsupport.dolby.co...language=en_US

I wonder how well it works in real life.
Actually system may be bit limited in functionality atm.

Last edited by kolak; 13th December 2022 at 00:29.
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Old 23rd December 2022, 08:21   #364  |  Link
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Quote:
Originally Posted by kolak View Post
Maybe Dolby did:
https://professionalsupport.dolby.co...language=en_US

I wonder how well it works in real life.
Actually system may be bit limited in functionality atm.
And BTW, it is not dark basement. That would require 2.6 gamma for SDR. It is just dark room with 5 nits of D65 lamps. So 5 candles not in front of the TV.

Dolby IQ works great, just as D93 light color managment. The patent on Dolby IQ is solid. Just like for TrueTone though.

See IQ patent. It is fuxxing nuts. https://patents.google.com/patent/WO2018119161A1/en

Last edited by Balling; 23rd December 2022 at 08:40.
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Old 27th December 2022, 04:03   #365  |  Link
wswartzendruber
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Jack Daniel's thoughts follow:

The HLG EOTF doesn't scale the display outlet linearly. As it increases brightness, the gamma value changes. If the HLG EOTF is doing this, then I should have pq2hlg do this when --lum-scale is applied.

I need to do the math (I suck at math) abstract the HLG parts out of a working model.
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Old 30th December 2022, 17:40   #366  |  Link
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The Lord of the Rings appears to have reference white at 100 nits. This is with linear brightness scaling.

The Argonath
Isildur's Account
A Wizard Is Never Late...
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Old 12th January 2023, 00:07   #367  |  Link
Balling
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Ambient environment SEI is now apparently used by iPhone, so they can reproduce D65 or D93 illuminants, or ony color as white point. Nice. https://patchwork.ffmpeg.org/project...bjp@gmail.com/


Applied!! https://github.com/FFmpeg/FFmpeg/com...c76812265157c5

ffprobe -select_streams v:0 -show_frames -i "iPhone11_4K-recorder_59.940DV+HLG.mov"
Quote:
[SIDE_DATA]
side_data_type=Ambient viewing environment
ambient_illuminance=3140000/10000
ambient_light_x=15635/50000
ambient_light_y=16450/50000
[/SIDE_DATA]
[SIDE_DATA]
side_data_type=Dolby Vision RPU Data
[/SIDE_DATA]
[SIDE_DATA]
side_data_type=Dolby Vision Metadata
rpu_type=2
rpu_format=18
vdr_rpu_profile=1
vdr_rpu_level=0
chroma_resampling_explicit_filter_flag=0
coef_data_type=0
coef_log2_denom=23
vdr_rpu_normalized_idc=1
bl_video_full_range_flag=0
bl_bit_depth=10
el_bit_depth=10
vdr_bit_depth=12
spatial_resampling_filter_flag=0
el_spatial_resampling_filter_flag=0
disable_residual_flag=1
vdr_rpu_id=0
mapping_color_space=0
mapping_chroma_format_idc=0
nlq_method_idc=-1
nlq_method_idc_name=none
num_x_partitions=1
num_y_partitions=1
[COMPONENT]
pivots=63 132 362 618 874 911 927 935 942
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=-409680 16721463 -20276640
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=-119056 13575212 -12867889
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=1317527 5338528 -948122
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=2119979 2065496 2288524
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=7982780 -11367226 9973944
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=53792084 -114243184 67724328
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=112973872 -244837568 139764480
[/SECTION]
[SECTION]
mapping_idc=0
mapping_idc_name=polynomial
poly_order=2
poly_coef=236828416 -518849056 291306944
[/SECTION]
[/COMPONENT]
[COMPONENT]
pivots=0 1023
[SECTION]
mapping_idc=1
mapping_idc_name=mmr
mmr_order=3
mmr_constant=-4200453
mmr_coef=9094176 31944476 739652 -27103344 -3431599 -11015088 22758042 -2028643 -30021218 -906885 26272992 7291404 16488745 -78087176 -1487777 12496543 762460 -4281948 -5768035 -7843163 103636960
[/SECTION]
[/COMPONENT]

Last edited by Balling; 15th January 2023 at 14:05.
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Old 17th February 2023, 22:24   #368  |  Link
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Some document which may have useful info:

https://www.itu.int/dms_pub/itu-r/op...2019-PDF-E.pdf
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Old 22nd February 2023, 00:17   #369  |  Link
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It looks like we only need to mess with gamma when increasing brightness due to the ambient environment providing distractions?
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Old 23rd February 2023, 17:09   #370  |  Link
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No idea. I just shared doc thinking it may be useful.
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Old 4th March 2023, 06:37   #371  |  Link
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Is Ultraviolet/infrared light as ambient white allowed? Interesting.
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Old 4th March 2023, 06:41   #372  |  Link
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Quote:
Originally Posted by wswartzendruber View Post
It looks like we only need to mess with gamma when increasing brightness due to the ambient environment providing distractions?
It is not only gamma, it is primaries too. Anyway. E.g., imagine you have Ledvance, former OSRAM, halogen lamps. Twelve of 12 V 300 lumen, so 12 V can be direct current too, so no pulses from alternating current. On the newer 2021 generation there is QR code into EU database EPREL (European Product Registry for Energy Labelling), this is mine https://eprel.ec.europa.eu/screen/pr...igatingfrom=qr

As you can see it has Correlated colour temperature 2 800K and Chromaticity coordinate
x: 0,452 y: 0,409, that is far from D65 6504 K x: 0.31271 and y: 0.32902. Lol.

Last edited by Balling; 4th March 2023 at 06:50.
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Old 13th April 2023, 02:10   #373  |  Link
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Version 1.1.0 is out.

Included in this release are:

1. The new hlg2pq utility, which allows for conversion to PQ at arbitrary display levels up to 10,000 nits.

2. Adding --hlg-compensate (-c) to pq2hlg, which addresses excessive saturation in a single channel by diverting to the other two channels.

3. The pqprev.sh / pqprev.ps1 script, which will grayscale a PQ frame and output it as an sRGB image without adjustment.

https://github.com/wswartzendruber/h...elease%2F1.1.0
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Old 19th August 2023, 01:42   #374  |  Link
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I'm starting to learn about how to run a YouTube channel. I've started a playlist that features various commercial HDR10 demos converted into HLG.

https://www.youtube.com/playlist?lis...HKMsJiYkzYRm1e
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Old 26th November 2023, 06:19   #375  |  Link
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I've been doing reading on how to best increase image exposure. Because when we're adjusting reference white, that's really what we're doing. I've posted two test clips onto YouTube. The first increases exposure by multiplying the linear RGB values by a factor. The second increases exposure by converting to Oklab and multiplying those components by a factor.

RGB: https://youtu.be/XMdFweclflY
Oklab: https://youtu.be/9hqkMBvwqSc

I'm interested in what others think of the results, as there doesn't seem to be an objectively correct way of doing this.

EDIT: Here are some screenshot comparisons for BT.709 playback via YouTube:










Last edited by wswartzendruber; 26th November 2023 at 18:34.
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Old 1st December 2023, 07:36   #376  |  Link
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Here's 2.0.0-beta1.

All brightness scaling is now based on Oklab. In other words, for all the pictures in the preceding post, 1.x (linear RGB scaling) is shown on the left while 2.0.0-beta1 (Oklab scaling) is shown on the right.

To this end, the --lum-scale (-l) flags are gone and replaced with --exposure (-e).
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Old 3rd December 2023, 05:40   #377  |  Link
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Here's 2.0.0-beta2.

This features newly-derived RGB<->XYZ matrices using the constants defined in BT.2020 as a starting point at 64-bit float precision.

These new matrices allow for a RGB<->Oklab roundtrip with accuracy to 0.0000000001 nits across all brightness levels.

Last edited by wswartzendruber; 3rd December 2023 at 05:43.
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Old 3rd December 2023, 11:46   #378  |  Link
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Quote:
Originally Posted by wswartzendruber View Post
I'm interested in what others think of the results, as there doesn't seem to be an objectively correct way of doing this.
Don't you have the SDR BluRay to compare against? There you should be able to see how deep the blacks are.

The point is, that of course the one with deeper black seems to look better, subjectively. However, I would be afraid that this might drown all blacks to black.

Last edited by ErazorTT; 3rd December 2023 at 12:00.
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Old 3rd December 2023, 13:55   #379  |  Link
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SDR will be most likely grading trim from HDR, so it's creative step (not some fixed math). It's not that easy to say which one is correct as there is no such a thing like "one correct SDR version". Typically official directors grade is reference and in case of HDR/SDR one can be sometimes quite different than other.
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Old 3rd December 2023, 16:27   #380  |  Link
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The objective with incorporating Oklab is to say: "The HDR10 grading represents some artistic intent. That intent should be preserved as the exposure is adjusted to increase reference white."

RGB is not perceptually uniform.
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