DCP Export Brightness Levels Lower (?)

[chinshort]

Hello!

Converting ProRes4444 to DCP, and facing some issues with the brightness levels/gamma(?)
Not sure if this question has been answered before.
I was wondering if this drop in brightness is normal?

Comparing VLC snapshots on Premiere Pro with scopes.

My source settings are as follows:

Video
ID: 1
Format : ProRes
Format version: Version 1
Format profile: 4444
Codec ID : ap4h
Duration: 35 s 833 ms
Bit rate mode: Constant
Bit rate : 220 Mb/s
Width: 1 998 pixels
Height: 1 080 pixels
Display aspect ratio: 1.85:1
Frame rate mode: Constant
Frame rate: 24.000 FPS
Color space: YUV
Chroma subsampling: 4:4:4
Scan type: Progressive
Bits/(Pixel*Frame): 4.247
Stream size: 939 MiB (99%)
Writing library: adb0
Language: English
Encoded date: UTC 2023-04-10 08:43:03
Tagged date: UTC 2023-04-10 08:43:03
Color primaries: BT.709
colour_primaries_Original: BT.709
Transfer characteristics: BT.709
transfer_characteristics_Origi : BT.709
Matrix coefficients: BT.709
matrix_coefficients_Original: BT.709

My output settings is as follows (as attached):

A1 DOM settings.PNG (13.97 KiB) Viewed 627 times

Colour: Rec709
Range Video (MPEG, 16-235)

Source:

A4 Source Levels PP.PNG (1.01 MiB) Viewed 627 times

Export:

A5 Export Levels PP.PNG (1.11 MiB) Viewed 627 times

[Carsten]

You should try rec.1886 (different gamma) in DCP-o-matic.

Had a few discussions about rec.709 vs. rec.1886 on the forum before, e.g.

https://dcpomatic.com/forum/viewtopic.php?p=9460#p9460

https://dcpomatic.com/forum/viewtopic.php?p=9132#p9132

Also, VLC snapshots are useful, but it's not a calibration reference.

[chinshort]

I've actually tried different gamma levels and they all result in a similar drop in the brightness levels.

Premiere Timeline:

PPstack.PNG (6.43 KiB) Viewed 615 times

Levels Difference:

DCP-Levels.png (581.06 KiB) Viewed 615 times

Not sure if I'm doing something wrong on export?

[Carsten]

This is not a proper calibrated roundtrip workflow, using three different applications, each which it's own color conversion.

You should probably also export the DCP from DCP-omatic as Prores.

Not sure what you are trying to achieve. You need to take your DCP to a calibrated cinema in order to judge proper levels.

[chinshort]

Just trying to find out why there's a drop in brightness levels after the export.

Will try to export the DCP from DOM as ProRes and give it a go.

Will update after! Thanks!

[chinshort]

Update on this,

Source ProRes4444, exported to DCP from DCP-O-Matic(DOM), put DCP back into DOM, exported ProRes4444 from DCP generated from DOM, and the drop in brightness level is present in the ProRes4444 export as well.

[carl]

Source ProRes4444, exported to DCP from DCP-O-Matic(DOM), put DCP back into DOM, exported ProRes4444 from DCP generated from DOM, and the drop in brightness level is present in the ProRes4444 export as well.

What are you using for "video range" for the ProRes444 file when you make the first DCP in this test?

[chinshort]

For this test - it is Video (MPEG, 16-235)