EasyDCP color space settings? Result is too bright -resolved

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zachnfine

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EasyDCP color space settings? Result is too bright -resolved

PostSun Jul 15, 2018 3:18 am

I have a timeline that's primarily full of 2k DPX files, scanned from film.
My Video Monitoring settings for the timeline are with Video data levels. Timeline Color Space is Rec.709 Gamma 2.4. I calibrated my projector to Rec.709 Gamma 2.4.

After grading, I made a 2k DCI flat DCP (interop, not SMPTE) from this timeline using the easyDCP plugin. I left the Data Levels for the export set to "Auto", expecting that Resolve and EasyDCP would handle any scaling and colorspace conversions necessary.

I copied the resulting DCP to an ext2-formatted drive and today ingested it into a GDC server connected to a Christie projector, and the result played just fine -- but the black level appeared to be elevated and the image washed out. The projectionist switched the Christie projector from what he said was the cinema standard "Unity RGB", to “RGB 10-bit 64-940”, and suddenly everything looked perfect - the black levels were back to normal, the picture was once again saturated and not overly-bright. This suggests to me that the DCP I’ve made has video levels rather than full range data levels, as 64-940 is the 10-bit version of 16-235.

But when I import that DCP into Resolve in the Media tab and have a look at it, it looks fine. If I set its clip attributes to video levels, it looks very crushed, with all the shadows clipping completely to black. This can be seen in both Resolve's software scopes and on my external scope. This suggests to me that the DCP is full range, not video levels.

If the DCP is full range, then why did it not look right on the Christie until that projector was set to the equivalent of video levels? If it's video levels, why does it not show up as such when brought into Resolve (or any of the freely-available DCP players -- it looks fine in DCP-o-Matic Player and seems to be ok in easyDCP Player Trial).

I'm left scratching my head on this one, and my ability to figure out the solution is limited by my access to a DCP server and projector.

I could send out the DCP for projection, with a note attached saying that Christie projectors should be set to the "RGB 10-bit 64-940" color space setting. But I don't know the equivalent setting name for all other projectors on which this film might be shown (it's a fairly small independent film that's about to go do a series of press screenings). The projectionist at today's test said they typically have that projector set to "Unity RGB", but sometimes have to switch it to "RGB 10-bit 64-940", even for released films from studios. He says they generally watch a couple of scenes and figure out the right setting. Is that really how this process works, or is there a standard way for me to indicate how this file should be projected? And of course, if I'm to indicate something like "video levels" or "64-940", is that really what this file is? I can't seem to verify that with any of the software I've found.

I've done a test export DCP of a minute of the film with the Export > Video > Advanced Settings > Data Levels explicitly set to "Full rather than "Auto". But as far as I can tell by bringing the file into Resolve and into DCP player software, this has the same levels as that initial DCP I'd made with the "Auto" setting. But maybe setting this explicitly would tell EasyDCP to flip some bit in the MXF file such that it will be interpreted as Full range by the DCP server?

Confusion reigns.

On the plus side, the image and sound were great, except for that whole "what are this file's video levels and how do I get projectors to always display it properly" issue.

Thanks for any help or information.


Resolve 15.0.08.065 (beta), macOS 10.13.5
edited to mention "interop"
Last edited by zachnfine on Tue Jul 17, 2018 1:13 am, edited 1 time in total.
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Peter Chamberlain

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Re: EasyDCP color space settings? Result is too bright

PostSun Jul 15, 2018 6:22 am

Why did you set your monitor output to data levels?
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Michael Tiemann

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Re: EasyDCP color space settings? Result is too bright

PostSun Jul 15, 2018 10:35 am

My reading of the OP is that he set his monitor to "Video data levels" aka "Video levels" not "Data levels".
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zachnfine

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Re: EasyDCP color space settings? Result is too bright

PostSun Jul 15, 2018 9:18 pm

Yeah, monitor's HD and at video levels.
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zachnfine

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Re: EasyDCP color space settings? Result is too bright

PostMon Jul 16, 2018 2:25 am

This wasn't at a multiplex, but at a studio's screening room, so it's possible (however unlikely) that something's mis-configured on the projector. I tested my DCP on a different projector (a Sony) at a teaching facility earlier in the week and it also looked too bright in the same manner, though that projectionist didn't think to change the color space setting and I didn't know at the time that this was an option.

So I'm worried because my DCP looked like video levels being interpreted as full range when played on these DCP servers and projectors, but it appears to be full range when imported into Resolve. And I don't know what settings I could possibly have in my configuration that'd be different than those for which easyDCP was designed.

easyDCP player trial's info panel for the DCP shows no 'color space' information is set in the MXF header, for what it's worth no colorspace was set in that metadata field for the little test DCP I made with DCP-O-Matic either, so maybe no software actually ever sets that. It just seemed like something to check. Likely red herring.

I'm making a new DCP from DPX with the advanced setting under output set to explicitly output full range rather than leaving it set to Auto. When I did a test with these settings of a small section, it looked the same to me when imported back into Resolve as the same section exported with that 'Auto' setting, and both appeared to be full range as far as I can tell by manually setting the clip attributes after import to see what happens to the image. But I'll hopefully get a chance to look at it on one of those DCP servers/projectors tomorrow.
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zachnfine

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Re: EasyDCP color space settings? Result is too bright -reso

PostTue Jul 17, 2018 1:21 am

Problem resolved!

I got a chance to go back to that Christie projector and do another test with some additional DCPs I exported for the purpose. It turns out that the "RGB 10-bit 64-960" (video levels) setting only brought my material back into the ballpark because of how far out of whack the projector had been set to begin with. It was at gamma 2.2 (explaining the low saturation, low contrast, and part of the over brightness), and was spitting out 19 foot lamberts.

We got it set back to the standard cinema settings of "Unity RGB", 2.6 gamma, and lowered the light output to 14 foot lamberts, and my DCP looked exactly as it should.

So the problem was never Resolve or easyDCP or the levels in the DCP. The fact that I tried playing my DCP on two projectors and both displayed it too bright in similar manners tells me that I'll need to attach a note to the DCP saying "Please display at 2.6 gamma and 14Fl". Those may be standard settings, but maybe it's worth reminding projectionists to check.

I'm grateful to the projectionists who let me run these tests (I won't name 'em as I don't know if this requires institutional permission), and sorry to take up your bandwidth with my non-problem. With any luck some of this information will be of use to anyone encountering a similar problem in the future (i.e. check the projector's settings and output level).
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zachnfine

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Re: EasyDCP color space settings? Result is too bright -reso

PostTue Jul 17, 2018 1:22 am

One more thing -- in case you're wondering what data is actually present in your DCP and want to corroborate what you're seeing in Resolve's scopes when you import it for a check -- DCP-O-Matic can import DCP, and it includes a nice waveform display in its "Tools" menu.

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