ACES and DCP gamma

Get answers to your questions about color grading, editing and finishing with DaVinci Resolve.
  • Author
  • Message
Offline

David Cherniack

  • Posts: 496
  • Joined: Wed Mar 08, 2017 10:01 pm

ACES and DCP gamma

PostSun Aug 26, 2018 10:27 pm

I have an ACES project outputting via 709 transform. I set up a test Deliver to a Kakatu DCP and looked at it in the DCP-o-matic player. The gamma is darker (probably 2.6 vs 2.4) than the 709 output. I would have thought that Resolve might do the gamma shift automatically but apparently not. Does this mean that I should set the OT to p3-DCI before rendering?

Also I downloaded DCP-o-matic because when I import the DCP mxf into Resolve there seems to be no input ACES transform from XYZ. Is there a LUT somewhere?
David
Resolve Studio 16 latest build
Windows 10 Pro
Decklink Mini Monitor 4k Desktop Video
Intel i9 7960x @ 4.3GHz
Thermaltake Floe Riing 360 Water Cooler
Asus x299 Prime Deluxe
64GB 3333 Corsair Dominator ram
2 EVGA 1080ti Cards
Areca Thunderbolt 3 Raid
Offline
User avatar

rick.lang

  • Posts: 13751
  • Joined: Wed Aug 22, 2012 5:41 pm
  • Location: Victoria BC Canada

Re: ACES and DCP gamma

PostMon Aug 27, 2018 4:14 am

David, what camera recorded the footage? You need to set the ACES IDT appropriate to the camera that created the image.


Sent from my iPhone using Tapatalk
Rick Lang
Offline

David Cherniack

  • Posts: 496
  • Joined: Wed Mar 08, 2017 10:01 pm

Re: ACES and DCP gamma

PostMon Aug 27, 2018 11:07 am

Thanks, Rick, I know. All the IDTs for the various input formats have been set correctly. That's not the issue at all. It's whether the ODT needs to be changed to P3-DCI (gamma 2.6) before making the DCP. I doubt it because that would likely also affect the gamut but the Kakatu DCP option is new so maybe there's some quirks and necessary workarounds, especially with ACES projects.
David
Resolve Studio 16 latest build
Windows 10 Pro
Decklink Mini Monitor 4k Desktop Video
Intel i9 7960x @ 4.3GHz
Thermaltake Floe Riing 360 Water Cooler
Asus x299 Prime Deluxe
64GB 3333 Corsair Dominator ram
2 EVGA 1080ti Cards
Areca Thunderbolt 3 Raid
Offline

David Cherniack

  • Posts: 496
  • Joined: Wed Mar 08, 2017 10:01 pm

Re: ACES and DCP gamma

PostMon Aug 27, 2018 12:49 pm

I ran some tests and changing the OT to P3 DCI is definitely NOT the solution. It doesn't correct the problem and alters the colour gamut.

To summarize what's happening:

Creating a Kakadu DCP output from and ACES project with a 709 OT with Deliver data levels set on Auto. Looking at the result in the DCP-o-matic player the blacks get severely crushed.

Changing the Deliver data levels to video the blacks are crushed a little and there is a slight yellow shift.

Either way the results do not look good in the DCP-o-matic player
David
Resolve Studio 16 latest build
Windows 10 Pro
Decklink Mini Monitor 4k Desktop Video
Intel i9 7960x @ 4.3GHz
Thermaltake Floe Riing 360 Water Cooler
Asus x299 Prime Deluxe
64GB 3333 Corsair Dominator ram
2 EVGA 1080ti Cards
Areca Thunderbolt 3 Raid
Offline
User avatar

waltervolpatto

  • Posts: 7961
  • Joined: Thu Feb 07, 2013 5:07 pm
  • Location: 1146 North Las Palmas Ave. Hollywood, California 90038 USA

Re: ACES and DCP gamma

PostMon Aug 27, 2018 2:03 pm

As a workaround, export a dpx sequence at rec709, make a new project with timeline at 709 and do the dcp from there
.
SuperServer 5039AD-I
C9X299-PGF - DDR4-2400 16x4 GB
i9-7920xCPU 12c 2.90GHz Water cooled
2x 1080ti DeckLink Studio 4K (11.5.1)
W10-1903 - BMR St. 16.2.2.012
nvidia: 441.66 studio
Offline
User avatar

JPOwens

  • Posts: 1509
  • Joined: Fri Apr 12, 2013 8:04 pm
  • Location: Victoria, British Columbia, Canada

Re: ACES and DCP gamma

PostMon Aug 27, 2018 3:30 pm

David Cherniack wrote: Looking at the result in the DCP-o-matic player the blacks get severely crushed.

Changing the Deliver data levels to video the blacks are crushed a little and there is a slight yellow shift.


Do you have any way of roundtripping an analytical project (bars, greyscale ramps, etc.) that can be scoped rather than eye-balled?

When I read "blacks are crushed", 9 out of 10 times it is because of a value range error. You should be able to open a DCP for at least 15 seconds of playtime natively in Resolve. I don't know if R15 will play the whole movie... I own a license of easyDCP for that express purpose.

jPo, CSI
Offline

Andrew Kolakowski

  • Posts: 6637
  • Joined: Tue Sep 11, 2012 10:20 am
  • Location: Poland

Re: ACES and DCP gamma

PostMon Aug 27, 2018 3:38 pm

Many versions later and DCP in Resolve is still a mess in short summary. There is basically no control over it and no real knowledge what is going on behind the hood.
Offline

David Cherniack

  • Posts: 496
  • Joined: Wed Mar 08, 2017 10:01 pm

Re: ACES and DCP gamma

PostMon Aug 27, 2018 6:21 pm

More tests and something useful to report.

My observation that blacks are crushed comes from the SMPTE bars at the begining of the timeline. The pluge chips disappeared except when I exported by video levels in which case they were too bright.

However,

Taking Walter's implied suggestion that the issue might be ACES, I had a DNxHR 12 bit RGB Quicktime export lying around. I pulled it in to a 709 project and exported an minute of DCP with the Kakadu non-interop setting. Interestingly that imported and converted in the viewer to 709 (where interop showed as XYZ unconverted in my ACES project) so I could look at the bars. The pluge and Resolve scope were dead on exact from the QT file.

So the blacks being crushed seems to have been caused by the DCP-o-matic player that crushed super blacks. I'd guess that the only way to know for sure is take it to a screening room with a DCP projector.
David
Resolve Studio 16 latest build
Windows 10 Pro
Decklink Mini Monitor 4k Desktop Video
Intel i9 7960x @ 4.3GHz
Thermaltake Floe Riing 360 Water Cooler
Asus x299 Prime Deluxe
64GB 3333 Corsair Dominator ram
2 EVGA 1080ti Cards
Areca Thunderbolt 3 Raid
Offline

David Cherniack

  • Posts: 496
  • Joined: Wed Mar 08, 2017 10:01 pm

Re: ACES and DCP gamma

PostTue Aug 28, 2018 6:36 pm

FYI the Demo of EasyDCP Player read the blacks correctly after I told it the file was full range. I couldn't find any option like that in DCP-o-matic.
David
Resolve Studio 16 latest build
Windows 10 Pro
Decklink Mini Monitor 4k Desktop Video
Intel i9 7960x @ 4.3GHz
Thermaltake Floe Riing 360 Water Cooler
Asus x299 Prime Deluxe
64GB 3333 Corsair Dominator ram
2 EVGA 1080ti Cards
Areca Thunderbolt 3 Raid

Return to DaVinci Resolve

Who is online

Users browsing this forum: gyorfitam, RedRider14, totalvamp and 76 guests