HDR workflow question - where to find master display data?

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Krzysztof Gluszek

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HDR workflow question - where to find master display data?

PostThu Sep 06, 2018 7:37 pm

Hi
i am trying to learn HDR workflow with UM4.6k. I know how to grade and output HDR in resolve (more or less) but i have many problems with uploading files to youtube. I grade on oled panasonic EZ1000, i know it is not ideal solution but offline files looks great in HDR, TV recognizes hdr without any problem. So i render files (rec2020, st2084) to DHxHR HQX 12bit, i can play those files via resolve and decklink straight to TV ad it looks awesome in HDR. To upload to YT i use hybrid, i render h265 mkv and put medadata into them.
Files than looks very nice on tv when i play them offline from disk. But on YT colors are ugly, highlights are clipped and looks wrong in general in HDR and SDR after YT internal conversion. I think, that it is because i dont know what shoud i put into Master display (i attached screenshot from hybrid). Could anybody could tell me where to find master display data for panasonic EZ1000? Is this can couse the problem? Thanks
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Andrew Kolakowski

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Re: HDR workflow question - where to find master display dat

PostThu Sep 06, 2018 9:37 pm

You need to put what you graded your footage to which is your output color space in Resolve. Most likely it's P3 or Rec.2020 (or maybe just Rec.709)
Values looks strange, but they are just multiplied by constant value.

SMPTE ST 2086 mastering display color volume SEI info, specified as a string which is parsed when the stream header SEI are emitted. The string format is “G(%hu,%hu)B(%hu,%hu)R(%hu,%hu)WP(%hu,%hu)L(%u,%u)” where %hu are unsigned 16bit integers and %u are unsigned 32bit integers. The SEI includes X,Y display primaries for RGB channels and white point (WP) in units of 0.00002 and max,min luminance (L) values in units of 0.0001 candela per meter square. Applicable for HDR content.

Example for a P3D65 1000-nits monitor, where G(x=0.265, y=0.690), B(x=0.150, y=0.060), R(x=0.680, y=0.320), WP(x=0.3127, y=0.3290), L(max=1000, min=0.0001):

G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1)

For Rec.2020:
G(8500,39850)B(6550,2300)R(35400,14600)WP(15635,16450)L(10000000,1)

Don't use full range (pc), better to stick with limited as in case some app/hardware doesn't read this *** it will use limited by default.
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meimeiriver

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Re: HDR workflow question - where to find master display dat

PostMon Nov 04, 2024 10:04 am

Andrew Kolakowski wrote:Example for a P3D65 1000-nits monitor, where G(x=0.265, y=0.690), B(x=0.150, y=0.060), R(x=0.680, y=0.320), WP(x=0.3127, y=0.3290), L(max=1000, min=0.0001):

G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1)

For Rec.2020:
G(8500,39850)B(6550,2300)R(35400,14600)WP(15635,16450)L(10000000,1)

Don't use full range (pc), better to stick with limited as in case some app/hardware doesn't read this *** it will use limited by default.


When re-encoding with x265, dgdecodenv always handily gives me this type of info on existing HDR movies, like:

Code: Select all
--colorprim 9 --transfer 16 --colormatrix 9 --master-display "G(8500,39850)B(6550,2300)R(35400,14600)WP(15635,16450)L(10000000,1)" --max-cll "203,21" --frames 222217 --chromaloc 2


However, recently found an SDR2HDR VapourSynth filter. It works great! But now I have a chicken-and-the egg situation, where I don't have the master-display data yet for the newly created HDR movie (because converted movie hasn't been written to disk yet), but in order to write it to disk, I will need the master-display data first!

So, how can I obtain the needed master-display info? (Preferably while inside the filter). Thanks.
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Andrew Kolakowski

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Re: HDR workflow question - where to find master display dat

PostTue Nov 05, 2024 12:12 pm

You need final HDR file to get stats. Resolve can do HDR10+ analysis and report needed values.
You can also skip master display data (and max-cll) as not many players use it anyway.

I think there is also some filter in vpy to get this data.
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meimeiriver

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Re: HDR workflow question - where to find master display dat

PostTue Nov 05, 2024 9:50 pm

Andrew Kolakowski wrote:You need final HDR file to get stats. Resolve can do HDR10+ analysis and report needed values.
You can also skip master display data (and max-cll) as not many players use it anyway.

I think there is also some filter in vpy to get this data.


Thanks for your reply.

Maybe I can get a good Black Friday deal on Davinci Resolve 19? :)

I did find a LUT conversion filter for VapourSynth; it produces HLG (and PQ with master-display data); but yeah, for PQ I would need the master-display data... or not, like you say :) I have not encountered a VapourSynth filter to collect PQ master-display data yet, though (or max/min CLL values, for that matter).
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Andrew Kolakowski

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Re: HDR workflow question - where to find master display dat

PostWed Nov 06, 2024 7:25 pm

Dolby Professional tools are free now and it can provide all needed info.
You just need to create a free account.
https://customer.dolby.com/content-crea ... tools-v550

Master display data is just a P3 or Rec.2020 coordinates and min and max light which it was graded to, so nothing to 'collect'. You know it. You calculate MaxCLL and MaxFALL.
Last edited by Andrew Kolakowski on Wed Nov 06, 2024 7:53 pm, edited 2 times in total.
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Cary Knoop

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Re: HDR workflow question - where to find master display dat

PostWed Nov 06, 2024 7:47 pm

Krzysztof Gluszek wrote:Hi
i am trying to learn HDR workflow with UM4.6k. I know how to grade and output HDR in resolve (more or less) but i have many problems with uploading files to youtube. I grade on oled panasonic EZ1000, i know it is not ideal solution but offline files looks great in HDR, TV recognizes hdr without any problem. So i render files (rec2020, st2084) to DHxHR HQX 12bit, i can play those files via resolve and decklink straight to TV ad it looks awesome in HDR. To upload to YT i use hybrid, i render h265 mkv and put medadata into them.
Files than looks very nice on tv when i play them offline from disk. But on YT colors are ugly, highlights are clipped and looks wrong in general in HDR and SDR after YT internal conversion. I think, that it is because i dont know what shoud i put into Master display (i attached screenshot from hybrid). Could anybody could tell me where to find master display data for panasonic EZ1000? Is this can couse the problem? Thanks

Why are you using data levels? I would stick with video levels for the whole pipeline. YouTube expects video levels.
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meimeiriver

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Re: HDR workflow question - where to find master display dat

PostThu Nov 07, 2024 10:05 am

Andrew Kolakowski wrote:Dolby Professional tools are free now and it can provide all needed info.
You just need to create a free account.
https://customer.dolby.com/content-crea ... tools-v550

Master display data is just a P3 or Rec.2020 coordinates and min and max light which it was graded to, so nothing to 'collect'. You know it. You calculate MaxCLL and MaxFALL.


Thank you kindly. This was very illuminating. :)

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