HDR -> SDR conversion

These CUDA filters are packaged into DGDecodeNV, which is part of DGDecNV.
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zys4416
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Re: HDR -> SDR conversion

Post by zys4416 »

admin wrote:
Fri Aug 30, 2019 8:21 am
zys4416 wrote:
Fri Aug 30, 2019 3:17 am
i'm very looking forward to the HLG2SDR function.
I didn't make one because of the supposed backwards compatibility of HLG. Can you further justify your request?
I have same 2160p 10-bit TS sources in HLG / BT.2020 (mediainfo reported), and I want to re-encode them to 1080p in SDR / BT.709 for archiving.

When I play a TS source, the color looks mostly fine, it seems to be a 4K UHD source.

You mean that I can re-encoding without any filters?
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admin
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Re: HDR -> SDR conversion

Post by admin »

Any chance you could give me a link to one of those transport streams? You can use DGSplit to cut the first 50MB. Only you can decide if it looks "good enough" with no special processing. With one of your streams I can try it both ways and we'll see how they compare.
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zys4416
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Re: HDR -> SDR conversion

Post by zys4416 »

admin wrote:
Tue Sep 03, 2019 8:50 am
Any chance you could give me a link to one of those transport streams? You can use DGSplit to cut the first 50MB. Only you can decide if it looks "good enough" with no special processing. With one of your streams I can try it both ways and we'll see how they compare.
I have provided 3 clips, 50MB per clip, thank you for your help :D

http://138.68.0.28:8008/trim_162.ts
http://138.68.0.28:8008/trim_187.ts
http://138.68.0.28:8008/trim_203.ts
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admin
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Re: HDR -> SDR conversion

Post by admin »

Thank you very much. I will make a proper HLG to SDR filter and see how it compares.
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admin
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Re: HDR -> SDR conversion

Post by admin »

This is interesting:

https://www.youtube.com/watch?v=yGSjun9gsbs

It shows that, compared to a proper conversion to SDR 709, playing HLG 2020 directly is "OK" but it is much darker and there are color shifts.

Probably your clips will perform similarly. Seems to me there is indeed a good justification for a new filter.
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admin
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Re: HDR -> SDR conversion

Post by admin »

Guys, I have added a 'HDR' field to the HEVC Info dialog. This will show "PQ" for HDR10, "HLG" for HLG, and is blank for SDR.

I also figured out how to properly detect HDR. There are two ways to signal it: 1) through the transfer_characteristics (16 is PQ, 18 is HLG), and 2) through SEI messages. Previously I was looking only at the presence/absence of SEI messages. Now I look at both. You have to look at both because a HLG stream can signal 709 via transfer_characteristics together with a preferred_transfer_characteristics SEI specifying HLG. This allows for backward compatibility of HLG with 709 displays. Refer to T-REC-H.Sup18-201710-I!!PDF-E.pdf for details:

https://www.itu.int/rec/T-REC-H.Sup18-201710-I

Will slipstream it after some regression testing.
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zys4416
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Re: HDR -> SDR conversion

Post by zys4416 »

I found the official HD version here:

https://www.youtube.com/watch?v=ih1l6wb7LhU

for these clips:

trim_187.ts at 35:03
trim_203.ts at 38:02

I can't find trim_162.ts in HD version, I think SDR ver. and HDR ver. are different editions.
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admin
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Re: HDR -> SDR conversion

Post by admin »

Thanks but I don't know how to download youtube videos.
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Bullwinkle
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Re: HDR -> SDR conversion

Post by Bullwinkle »

Hello there culture lovers. Today we take a look at the modern day HLG to SDR known as The Good Stuff. Here is one fetching picture. They call me fetching. Fetching all the pixels ain't saving whoa! Ooh. Okay that is all for today next week the meaning of Randomness and Beauty.
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admin
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Re: HDR -> SDR conversion

Post by admin »

Whee!
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zys4416
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Re: HDR -> SDR conversion

Post by zys4416 »

admin wrote:
Thu Sep 05, 2019 1:27 pm
Thanks but I don't know how to download youtube videos.
https://www.vidpaw.com/

or

https://www.findyoutube.net/
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

Thank you, zys4416.

I have the HLG EOTF coded and apparently working. I want to compare the results to the HD versions you linked, and also to the results of some other conversion filters. If things look good, I'll implement it fully into DGHDRtoSDR (with a mode parameter for PQ or HLG) and add it to DGIndexNV as well.
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Bullwinkle
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Re: HDR -> SDR conversion

Post by Bullwinkle »

Sure but watch me pull a rabbit out of a hat... Ooh not what I had in mind randomness is beautiful.
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

Just discovered there is a BT.2100-2 while I was coding off of BT.2100-1. The HLG EOTF is a bit different in BT.2100-2 so I'll have to revise the implementation accordingly. No big deal.
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

I tried both of these. Each simply brought up a player and played the stream. I could not see how to download the stream.
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zys4416
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Re: HDR -> SDR conversion

Post by zys4416 »

Rocky wrote:
Mon Sep 09, 2019 8:21 pm
I tried both of these. Each simply brought up a player and played the stream. I could not see how to download the stream.
Just one step, right-click on the player and select "Save video as..." :D
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

Great, thank you. You are so kind.
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

I've got the HLG EOTF re-coded and working. And I have DGHDRtoSDR() modified to support both PQ and HLG via a mode parameter. I'll add the HLG support to DGIndexNV and then give y'all both of them. Whee!
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hydra3333
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Re: HDR -> SDR conversion

Post by hydra3333 »

Whoopee :)
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

I've got HLG to SDR working in DGIndexNV. It's kinda nice. You can set up the HLG conversion and then just click and unclick 'Enable HDR to SDR' to see the difference between real HLG conversion and backwards compatible display. The color shifts from backwards compatible handling become very obvious.

Now I have to do code reviews, regression testing, and documentation.
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hydra3333
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Re: HDR -> SDR conversion

Post by hydra3333 »

Nice work. Looking forward to seeing demos :salute:
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

Thanks. Gonna be a few days as I have to complete some coaching certification renewal training first.
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Re: HDR -> SDR conversion

Post by Rocky »

Finished all my certs, concussion protocol and doping stuff was new this year. Good to go until end of 2020. :)

Back to work...
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Rocky
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Re: HDR -> SDR conversion

Post by Rocky »

OK, girls and boys, I have stuff ready for your testing. I want to wait for your feedback before releasing formally. The package is here:

http://rationalqm.us/misc/hlg_test.rar

Please read the docs carefully as the parameters have changed. This was quite a non-trivial revision so your careful testing under Avisynth+ and Vapoursynth (native), as well as checking the docs, would be very helpful. Thank you and have fun. :P

Delete your INI file first and then open and close DGIndexNV! Then begin testing.
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Bullwinkle
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Re: HDR -> SDR conversion

Post by Bullwinkle »

Sure, sure, thanks Rocky, but why bother when UHD is useless? People call me useful. Whoo. Look at the last figure on this page and tell me I am a foolish Moose.

https://www.lightillusion.com/uhdtv.html

Also, while we're pointing out the insanity remember that HDR10 PQ (absolute brightness) requires a very controlled viewing environment, and horrors metadata. But HLG is relative and a simple control can scale things very well for different environmental brightness. Just google up some PQ versus HLG action. PQ should be sent to Siberia!

https://www.smpte.org/sites/default/fil ... andout.pdf

Finally, this may enlighten you:

https://www.youtube.com/watch?v=--PyKhohVcY
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