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winoni71

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Join date
7-Mar-2021
Last activity
22-Aug-2021
Posts
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Post
#1420394
Topic
Info: Guide for Working with 4K HDR Blu-ray Rips in SDR
Time

Thank you all for the valuable tips.

44rh1n said:
**Important: Ensure “Mastering Display” is set to “1000-nit, BT.2020, D65, ST.2084, Full.” That is the correct option for most 4K Blu-rays. However, for some 4K Blu-rays that are mastered at 4000-nits, you’ll want to select the “4000-nit, BT.2020” option. ALSO: make sure the resolution and framerate are correct in the the Master Settings.

As for the 4000 vs 1000 nits, do I find the information in media info?
If not, how do I know which is which?

Could it be “Mastering display luminance” or “Maximum Content Light Level” (although in the second file this is higher than 4000)?

Thank you.

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
HDR format : SMPTE ST 2086, HDR10 compatible
Codec ID : hvc1
Codec ID/Info : High Efficiency Video Coding
Duration : 2 h 15 min
Bit rate : 62.8 Mb/s
Maximum bit rate : 110 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (23976/1000) FPS
Original frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.316
Stream size : 59.5 GiB (100%)
Encoded date : UTC 2021-03-28 11:31:48
Tagged date : UTC 2021-03-28 11:33:00
Color range : Limited
Color primaries : BT.2020
Transfer characteristics : PQ
Matrix coefficients : BT.2020 non-constant
Mastering display color pri : Display P3
Mastering display luminance : min: 0.0050 cd/m2, max: 4000 cd/m2
Maximum Content Light Level : 636 cd/m2
Maximum Frame-Average Light : 103 cd/m2
Codec configuration box : hvcC

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
HDR format : SMPTE ST 2086, HDR10 compatible
Codec ID : hvc1
Codec ID/Info : High Efficiency Video Coding
Duration : 2 h 7 min
Bit rate : 50.4 Mb/s
Maximum bit rate : 100 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (23976/1000) FPS
Original frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.253
Stream size : 44.8 GiB (100%)
Encoded date : UTC 2021-03-25 17:12:31
Tagged date : UTC 2021-03-25 17:13:24
Color range : Limited
Color primaries : BT.2020
Transfer characteristics : PQ
Matrix coefficients : BT.2020 non-constant
Mastering display color pri : Display P3
Mastering display luminance : min: 0.0050 cd/m2, max: 4000 cd/m2
Maximum Content Light Level : 4809 cd/m2
Maximum Frame-Average Light : 537 cd/m2
Codec configuration box : hvcC

Post
#1416201
Topic
Info: Guide for Working with 4K HDR Blu-ray Rips in SDR
Time

44rh1n said:

winoni71 said:
P.S.: I don’t’ understand something though, isn’t the HDR metadata supposed to be there precisely to determine, frame by frame or scene by scene, what the picture is supposed to look like?

HDR10 does not have metadata. It’s just plain old HDR (Rec.2020 ST.2084), and nothing else.

Dolby Vision has metadata which contains information that trims down the the Rec.2020 ST.2084 (HDR) source to a Rec.709 Gamma 2.4 (SDR) output. But to my knowledge, that metadata from the disc is only readable on a TV.

You could import the Rec.2020 ST.2084 source into DaVinci Resolve and run it through Resolve’s Dolby Vision scan, and that will give you brand new SDR metadata which you could use to export an SDR video. However, it won’t have the nuances and custom adjustments that the colorist would have made for the original Dolby Vision pass.

I should also note, as a reminder, that HDR footage is similar to log camera footage – meaning, it has much more latitude to work with than SDR footage. So if you’re doing fan restorations, it’s better to NOT bake in an SDR conversion. It’s best to do color work within HDR, and then have your SDR conversion at the very end of the chain. That’s the workflow that this tutorial of mine hopefully illustrates.

My head hurts, this is very confusing.
If there’s no metadata, then how can each scene be graded differently and why is it so difficult to make a conversion to SDR?

I’m not looking to make a restoration, but to have an “all-purpose” method to convert HDR to SDR while preserving (as much as possible, without grading scene by scene) the visual characteristics, I’m not looking for perfection.

Knowing this, having at my disposal both Abode Premier PRO and Resolve Studio, what would you recommend to achieve what I’m looking for?

Thank you.

Post
#1416169
Topic
Info: Guide for Working with 4K HDR Blu-ray Rips in SDR
Time

I tried the “SDR conform” effect and it’s quite good, although I’m not sure whether it could be improved.

Here are a few frames from “Back to the future”, 4 from my HDR to SDR conversion using “SDR conform” and the same 4 from the actual SDR Blu-ray version created from the same 4K master.

https://drive.google.com/uc?export=download&id=1SehhPMe_hZxZblh8CFd1DIxE6KgN0_nz

They’re slightly different, but I can’t honestly tell which is better, the SDR BD seems to have a reddish tint.

Thoughts?

Thank you.

P.S.: I don’t’ understand something though, isn’t the HDR metadata supposed to be there precisely to determine, frame by frame or scene by scene, what the picture is supposed to look like?

Post
#1415800
Topic
Info: Guide for Working with 4K HDR Blu-ray Rips in SDR
Time

krausfadr said:

winoni71 said:

Hello,
I am trying to convert a bunch of HDR movies into SDR using “TMPGEnc Video Mastering Works 7” which allows the use of LUT files and I was wondering if there’s someone here willing to help me out.

I have successfully imported the “Rec2020ToRec709_CSTDefault” LUT file, which I suppose is the one to use, and the results are good, but I’d like to make them better, but I’m not sure how.

Thank you.

The conversion LUTS (HDR > SDR) generally are fixing the overall overexposed and washed out look you would get without correction. The issue is that one LUT will not adequately correct every scene in a film. Each scene has different light and color, so to achieve good results you would have to color correct scene by scene, ideally using an NLE.

Adobe Premiere has a built in “SDR conform” tool, and while you can apply it to the entire video, you can also create an adjustment layer and tweak the SDR conform settings scene by scene.

Thanks for the reply.
What is an NLE?
Would the “SDR conform” tool in Adobe Premiere be the easiest and fastest way to convert multiple movies without correcting scene by scene?
I’m looking for the easiest way to do this, because I’m not going to correct scene by scene, that would take me days, if not weeks.

Thanks again.

Post
#1415765
Topic
Info: Guide for Working with 4K HDR Blu-ray Rips in SDR
Time

Hello,
I am trying to convert a bunch of HDR movies into SDR using “TMPGEnc Video Mastering Works 7” which allows the use of LUT files and I was wondering if there’s someone here willing to help me out.

I have successfully imported the “Rec2020ToRec709_CSTDefault” LUT file, which I suppose is the one to use, and the results are good, but I’d like to make them better, but I’m not sure how.

Thank you.