Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Announcements and Chat > General Discussion

Reply
 
Thread Tools Search this Thread Display Modes
Old 26th October 2022, 12:43   #221  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 2,417
Quote:
Originally Posted by wswartzendruber View Post
Psst! Remember that Apple sample...
Damn, I knew I was gonna forget!
Check your PM
FranceBB is offline   Reply With Quote
Old 26th October 2022, 21:17   #222  |  Link
wswartzendruber
hlg-tools Maintainer
 
wswartzendruber's Avatar
 
Join Date: Feb 2008
Posts: 345
Cool! I'll grab it when I get home.
wswartzendruber is offline   Reply With Quote
Old 27th October 2022, 00:52   #223  |  Link
wswartzendruber
hlg-tools Maintainer
 
wswartzendruber's Avatar
 
Join Date: Feb 2008
Posts: 345
That's BT.709 with HLG being falsely signaled in the bitstream.
wswartzendruber is offline   Reply With Quote
Old 27th October 2022, 09:22   #224  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 2,417
Quote:
Originally Posted by wswartzendruber View Post
That's BT.709 with HLG being falsely signaled in the bitstream.
hahahahahahaha
Apple iPhone Pro? More like Apple screw up pro then!

But no, seriously, that cannot be.
It is indeed BT2020 with HLG in it in fact:

(disclaimer: the picture shows one of our F1 journalists doing a speech)



The problem is that the camera sensor of the iPhone has really just a bunch of stops, so the resulting HLG will be bad and with really bad overshooting over the 0.52V (i.e 75% reference).


So... although it actually really is BT2020 HLG, it really doesn't introduce any improvement over a standard BT709 SDR recording as I'm pretty sure iPhone sensors barely have 6 stops (which is what you need for 100 nits...)



Now, I clearly cannot share the """master""" of the speech, but here's a more public sample I can share about a landscape: Link

The same goes for this sample depicting Christmas Lights, which is indeed BT2020 HLG with overshooting ('cause lights would require many more stops than the ones currently available in the iPhone):





On the left hand side, there's the displayed version assuming it as BT2020 HLG (correct) and on the right hand side there's the displayed version assuming it as BT709 SDR (not correct):




Still, does it make sense to have HLG on such a puny sensor? Probably not...
But you know, it's Apple, if they have like 7 stops and can turn the BT709 SDR 100 nits into a 175 nits BT2020 HLG, they'll call it HDR and scream to the whole world that they're great... :P

Last edited by FranceBB; 17th November 2022 at 11:45.
FranceBB is offline   Reply With Quote
Old 28th October 2022, 19:34   #225  |  Link
Balling
Registered User
 
Join Date: Feb 2020
Posts: 468
Quote:
Originally Posted by FranceBB View Post
I really hope so!
Google is getting there from Pixel 7 onwards, Samsung now moved to HLG, Apple uses a Dolby Vision profile but with HLG inside (although with arbitrarily set values), I think we're gonna see more and more of it in the next couple of years and that's a very good thing!
Samsung still uses PQ. My galaxy s22. Apple uses HLG with dolby vision meta to derive PQ.
Balling is offline   Reply With Quote
Old 31st October 2022, 06:09   #226  |  Link
Balling
Registered User
 
Join Date: Feb 2020
Posts: 468
>But you know, it's Apple, if they have like 7 stops and can turn the

iPhone 13 has 12 stops.
Balling is offline   Reply With Quote
Old 31st October 2022, 06:37   #227  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 2,417
Quote:
Originally Posted by Balling View Post
iPhone 13 has 12 stops.
For real or is it what they declared on paper like when they were fined for misleading info about their monitors?

It would be nice to see a sample.
The reason why I'm skeptical is that big sensors like the full frame one of the Sony A7 III have 15 stops, so it would really surprise me if Apple had 12 on their tiny sensors in their phones...
FranceBB is offline   Reply With Quote
Old 11th November 2022, 02:34   #228  |  Link
Majorlag
Registered User
 
Join Date: Jul 2016
Posts: 19
FranceBB,
I noticed that a few people where trying to get your wonderful LUT's to work better for them. I wanted to share the script I use to get HDR to SDR to work for me with PQ to SDR. This worked for Marsu42's sample clip without a custom LUT. This uses LaTo's SmoothAdjust 3.20 Avisynth plugin to change gamma, since HDR and SDR have different gamma levels. No need to figure out brightness levels of source. Tested on several clips with great results. Thanks again for your hard work in create those LUT's

#Bringing everything to 16bit
ConvertBits(16)

#Stack when working in 16bit precision for SmoothLevels
#HDR and SDR have different Levels, then unstack
#Lmode 3 to keep blacks from crushing, and white from greying
ConvertToStacked()
SmoothLevels16(HQ=true,preset="fullrange",gamma=0.8,Lmode=3)
ConvertFromStacked()

#Converting YUV to RGB with 16bit precision
ConvertToPlanarRGB()

#Tone-mapping HDR PQ to SDR LUT
Cube("C:\Program Files (x86)\AviSynth+\LUTs\PQ_to_BT709_v1.cube")

#Converting RGB to YUV 4:2:0 planar with 16bit precision
ConvertToYUV420()
Majorlag is offline   Reply With Quote
Old 15th November 2022, 13:41   #229  |  Link
Balling
Registered User
 
Join Date: Feb 2020
Posts: 468
Latest Davinci added profile 5 Dolby Vision decoder. Only MacOS.
Balling is offline   Reply With Quote
Old 15th November 2022, 19:35   #230  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 2,417
Quote:
Originally Posted by Balling View Post
Only MacOS.
bummer
FranceBB is offline   Reply With Quote
Old 16th November 2022, 02:18   #231  |  Link
wswartzendruber
hlg-tools Maintainer
 
wswartzendruber's Avatar
 
Join Date: Feb 2008
Posts: 345
Quote:
Originally Posted by Majorlag View Post
This uses LaTo's SmoothAdjust 3.20 Avisynth plugin to change gamma, since HDR and SDR have different gamma levels.
If this is true, then my hlg-tools converter is doing things wrong. Ultimately, I can't figure out how to scale brightness.

1. BT.1886 implies that SDR->HDR brightness scaling requires no gamma adjustment.

2. BT.2100 implies that gamma adjustment is absolutely necessary, and the HLG EOTF handles this.

3. BT.2446 states that it's optional.

wswartzendruber is offline   Reply With Quote
Old 16th November 2022, 05:48   #232  |  Link
Majorlag
Registered User
 
Join Date: Jul 2016
Posts: 19
I have not tested any HLG content. All the videos that I have dealt with are all PQ.

I could be wrong, I thought I read that HDR used a different gamma. Without changing the gamma, it looks a bit washed out, especially the sun and clouds in scenes using the LUTs. The gamma shift and LUTs are also much closer to SDR blu-ray of of the same UHD HDR clips that other plugins never seem to get close to.

I was mostly posting my script because I saw one of the previous posters wished it was a bit darker. I have never been a fan of the other scripts out there, so hopefully someone else finds it useful to them, or maybe have a starting point to run with it and improve. Again, never tested HDR HLG, at least with HDR PQ I get the results that is most pleasing to me after spending countless days trying to get HDR PQ sources to convert nicely
Majorlag is offline   Reply With Quote
Old 16th November 2022, 18:55   #233  |  Link
Majorlag
Registered User
 
Join Date: Jul 2016
Posts: 19
Quote:
Originally Posted by wswartzendruber View Post
If this is true, then my hlg-tools converter is doing things wrong. Ultimately, I can't figure out how to scale brightness.

1. BT.1886 implies that SDR->HDR brightness scaling requires no gamma adjustment.

2. BT.2100 implies that gamma adjustment is absolutely necessary, and the HLG EOTF handles this.

3. BT.2446 states that it's optional.

I found a recent article talking about different gamma at https://www.igorslab.de/en/all-aroun...itor-basics/2/. With Rec.709 at 2.4 and Rec.2020 at 2.2. This is the same that I have read from several sources for the last few years. Interesting BT.1886 I thought was 2.35 for gamma and is mentioned in that article as being between 2.2 and 2.4.

Maybe my method of madness is way off, but the end result was close, but changing it by 0.2 by changing the plugin's gamma value 1.0 (do nothing) to 0.8 resulted in satisfactory results for me and my setup. Not sure why I have to shift the gamma before the LUT, but it worked better before then after the 3d colour volume change.
Majorlag is offline   Reply With Quote
Old 30th November 2022, 07:32   #234  |  Link
Balling
Registered User
 
Join Date: Feb 2020
Posts: 468
"Interesting BT.1886 I thought was 2.35 for gamma and is mentioned in that article as being between 2.2 and 2.4."

It is 2.35, as in CRT true curve. Sony just moved to 2.4 after their reference LCD got better black point. And anyway, 2.4 is correct rounding for 2.35.

https://mixinglight.com/color-gradin...vinci-resolve/
https://referencehometheater.com/201...gamma-correct/

The article is garbage. sRGB does not use pure gamma, in fact nothing uses pure gamma nowadays (only Adobe RGB 1998).

From the article "I use C1 BT.1886 at home with my LG OLED, I personally like it better than Gamma 2.4 (matter of taste)."

What is the difference? Is BT.1886 using the light sensor as it should per BT.1886?

"and Rec.2020 at 2.2."

It does not say that. BT.1886 is used for it too.

Last edited by Balling; 30th November 2022 at 10:53.
Balling is offline   Reply With Quote
Old 1st December 2022, 03:47   #235  |  Link
Majorlag
Registered User
 
Join Date: Jul 2016
Posts: 19
I should clarify. The metadata of PQ HDR files that I deal with has "Color primaries:BT.2020" "Mastering display color primariesisplay P3"
Quote:
While Display P3 (comes from Apple) uses D65 (6500 K as in sRGB and Adobe RGB) and Gamma 2.2 (like sRGB). The D65 white point is now used internationally as a standard
The opinion of the quality of the article can be debated, however this is not the only site that has the same information referencing gamma 2.2 for HDR and 2.4 for SDR. That was just the most recent article I could find. Not sure what all claims the rest of the article talks about, it was more of a simplified explanation of why I find reducing gamma seems to work for my needs in converting HDR to SDR.
Majorlag is offline   Reply With Quote
Old 1st December 2022, 17:02   #236  |  Link
Balling
Registered User
 
Join Date: Feb 2020
Posts: 468
"referencing gamma 2.2 for HDR and 2.4 for SDR"

The article only talks about SDR. What??

"Mastering display color primaries Display P3"

You do understand that still means color primaries are BT.2020? Also, this is typo in Mediainfo. Display P3 is sRGB transfer. It actually means P3-D65.

Last edited by Balling; 1st December 2022 at 17:07.
Balling is offline   Reply With Quote
Old 6th December 2022, 23:20   #237  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 2,417
Quote:
Originally Posted by spoRv View Post
Bravo Francesco, ottimo lavoro!

I'm thinking if you can make two further LUTs:
XYZ to 2020 HLG
XYZ to 2020 PQ
Hey Sporv, I'm getting closer to satisfy your request.
I've added:

BT2020 HLG to DCI P3 D63 XYZ γ 2.6
BT2020 PQ to DCI P3 D63 XYZ γ 2.6




also check this out: https://forum.doom9.org/showthread.php?p=1979435
FranceBB is offline   Reply With Quote
Old 8th December 2022, 11:24   #238  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 2,417
Linear Transformation v2.3 Released!!

Quote:
Changelog:

- Introduced support to DCI P3 D63 XYZ conversion to/from BT2020 HLG & PQ as requested by Sporv.


LinearTransformation(Input="BT2100_PQ", Output="DCI_XYZ")

LinearTransformation(Input="BT2020_HLG", Output="DCI_XYZ")

LinearTransformation(Input="DCI_XYZ", Output="BT2020_HLG")

LinearTransformation(Input="DCI_XYZ", Output="BT2100_PQ")

https://github.com/FranceBB/LinearTr...tion/releases/


Note:
Please note that going back from DCI P3 D63 XYZ to PQ RGB is particularly hard and although I tweaked it on a few titles, the end result is supposed to be manually checked, especially 'cause this is all based on "static" MaxCLL assumptions which may not fit each and every case and for this very reason I wouldn't trust the conversion in a totally automatic process.
As far as HLG is concerned, however, you can safely "turn the autopilot on" and trust the conversion.
FranceBB is offline   Reply With Quote
Old 20th December 2022, 07:53   #239  |  Link
Balling
Registered User
 
Join Date: Feb 2020
Posts: 468
Adobe just released Camera Raw 15.1, that properly supports PQ surface on windows 11 for 48 megapixel DNGs from iPhone 14. It has insane HDR. My Galaxy S22 Ultra Expert RAW has NO HDR. Not even a pixel. WTF. Fake RAW, bad Samsung.

See some samples: crazy HDR https://www.dropbox.com/s/kl764411n9...W48MP.DNG?dl=1

Simple HDR: https://www.dropbox.com/s/ormope1xmz..._1138.DNG?dl=0

Almost no HDR: https://www.dropbox.com/s/rqyasvk2hw..._1151.DNG?dl=0

Last edited by Balling; 20th December 2022 at 13:57.
Balling is offline   Reply With Quote
Old 26th December 2022, 16:27   #240  |  Link
Dragon1981
Registered User
 
Join Date: Oct 2022
Posts: 3
Guys,
I like dolby vision profile v5 output converted through davinci resolve of the HDR (HLG) videos shot on my iPhone 12. Is it possible to have same kind of color output in SDR through some LUT?
Used FranceBB LUT for iPhone SDR export but it doesn't quite go near to DV v5 color matching.
Dragon1981 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 19:52.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2023, vBulletin Solutions Inc.