Davinci DNXhr444 export settings for DCPOM?

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resolver
Posts: 2
Joined: Sun Jul 14, 2019 10:23 am

Davinci DNXhr444 export settings for DCPOM?

Post by resolver » Sun Jul 14, 2019 10:35 am

Hi

I'd like to export a DNXHR 444 10bit mov from PC version of Davinci Resolve 15 for use in DCP-o-matic.

What are the correct export video levels to use, Full or Video?

I've read that Full is recommended but this looks too crunchy in DCPOM player.

Alternatively what output format and settings work best from PC Resolve that guarantee correct levels?

Any advice appreciated!

Carsten
Posts: 1397
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Davinci DNXhr444 export settings for DCPOM?

Post by Carsten » Sun Jul 14, 2019 6:38 pm

I suggest to use video levels, but you should be able to verify this with DOMs waveform monitor. It is easy to recognize a black level mismatch there. As a matter of fact, video vs. data level issues was the reason I suggested the video waveform monitor feature to Carl a long time ago.

What is your source range? Most people work from rec.709 with video levels, monitor in rec.709, and I suggest to deliver with video levels as well.


This one went through OpenDCP, and as OpenDCP forces to use image sequences as input source, there is always a risk to run into sRGB/rec.709 video range misinterpretation.
BlackLevelLift.png
BlackLevelLift.png (220.58 KiB) Viewed 850 times

I have seen the occasional adspot with the same issue. Our projection system shows excellent (low) black levels, so this issue comes out very obvious.
Proper black levels could extend to near zero, but at least well below 512.



- Carsten

resolver
Posts: 2
Joined: Sun Jul 14, 2019 10:23 am

Re: Davinci DNXhr444 export settings for DCPOM?

Post by resolver » Mon Jul 15, 2019 10:59 am

Thanks Carsten. The Video levels tool is brilliant!
The tool showed that the PC Resolve 15 DNXHR 444 10bit mov exported with Full levels has clipped highlights and shadows on ingest into DCPomatic and increased contrast.
The DNXHR 444 mov exported with video levels does not clip but appears to have a slightly elevated gamma in DCPOM.
A colourist guru I know suggested exporting Kaduku JPEG2000 files from Resolve and these give the closest match levels to
the original resolve rec 709 project once imported in DCPOM.

If I import the exported DCPs back into Resolve I observe the same shifts as noted above (Kaduku one is very close to original).

Both the Full and Video level DNX quicktimes import perfectly back into resolve so there may be something that needs adjusting in DCPOMs ingest levels mapping for Resolve exported DNX movs?

So now I'm hoping the 137,000 j2cs I've now exported dont cause DCPOM to croak - wish me luck!

Cheers

Carsten
Posts: 1397
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Davinci DNXhr444 export settings for DCPOM?

Post by Carsten » Mon Jul 15, 2019 11:43 am

There is an open feature suggestion for better/explicit video/data level support in DCP-o-matic (in the form of a custom color conversion parameter). The trouble is, you may have either video or data levels in video content (not just DNx) without this being flagged anywhere. So far, we can only assume that FFMPEG deals with this correctly (and that typically, video files contain video levels).

Resolve 15 should create DCI compliant J2C - that wasn't the case in previous Resolve versions. I don't know though, wether Resolve applies the same DCI constraints to image sequence J2C as it does for full DCP export.

- Carsten

carl
Site Admin
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Joined: Thu Nov 14, 2013 2:53 pm

Re: Davinci DNXhr444 export settings for DCPOM?

Post by carl » Wed Jul 17, 2019 3:37 pm

2.15.x has an option to specify the video range for content; it may not entirely work yet, but you might want to try it out.

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