Color grading when uploading to aggregator

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Zack_W

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Color grading when uploading to aggregator

PostFri Dec 01, 2023 7:19 pm

I have a complete a feature-length documentary that I will be uploading to a streaming aggregator (Filmhub, in this case). Material is all ProRes 422HQ, and the project is not color managed. I've done color correction on a hardware calibrated (Rec.709 gamma 2.4) monitor fed via an UltraStudio Monitor 3G box. I'll be exporting a ProRes 422HQ file, and within the "advanced settings" on the Deliver page I'll set the Color Space Tag to "Rec.709" and the Gamma Tag to "Rec. 709." So far so good, and in keeping with the information that so many people have generously shared in this forum (such as the 15-page "Final Explanation of Gamma and Color Shift Problems" thread!)

I'm still dealing with the dreaded gamma shift issue, whereby video players on Apple and PC platforms use different default gamma settings resulting in a video looking different depending on the operating system it is playing on. My understanding is that there is simply no way to control this, but I need to my videos to look as good as possible regardless of whether they are viewed in an Apple or PC ecosystem. When I upload a video to Vimeo or Youtube, I therefore add an adjustment layer to the entire film that adds some contrast and approximately splits the difference between how the video will look on a platform subject to Apple's color management and one that isn't. As a result, the video will still look a bit too flat when subject to Apple's color management, and a bit too crushed when viewed on any platform that is not subject to Apple's color management. But it's a decent compromise that will look acceptable on all platforms.

Here's my question: Should I include this color correction adjustment layer when I export the film for upload to an aggregator? I assume I should, since the aggregator will be selling the film to multiple different streaming channels that will be viewed on a random mixture of platforms, some using Apple's color management and some not using it. But possibly aggregators (or streaming channels) have their own techniques for dealing with the gamma shift issue, and I should therefore just upload the best-looking grade that I have and let the aggreagor/streaming channels deal with the problem?

Thanks for any advice! I'm sure someone will tell me to ask the aggregator, but Filmhub's technical support is not terribly responsive and I doubt that I'll get a useful answer! I'm using Resolve Studio 18.1.4 and working on an M1 Mac Mini running Mac OS 12.7.1
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Marc Wielage

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Re: Color grading when uploading to aggregator

PostSat Dec 02, 2023 4:01 am

Now I have to take another drink! Read these:

"Grading for Mixed Delivery: Cinema, Home, and Every Screen in Between" by Cullen Kelly
https://blog.frame.io/2019/10/14/gradin ... -delivery/

and

"How to Deal with Levels: Full vs. Video"
by Dan Swierenga
https://www.thepostprocess.com/2019/09/ ... l-vs-video

and I think both cover the issues and the solutions very well.

Understanding color management is also helpful:

"Color Management for Video Editors"
https://jonnyelwyn.co.uk/film-and-video ... o-editors/

The above articles will explain why things change on different displays, different playback engines, and the importance of calibration and color-managed outputs.

I generally try to export a second or two of SMPTE Bars at the head of the project, and I import the file back into Resolve to check it on scopes to verify all the levels are correct. Using calibrated displays is a must -- without that, you have no idea what you're looking at. We also accept that the basic picture is going to change a little bit on different devices, because that's life.

But the answer to your question: my advice is to grade it for Rec709/BT1886 (gamma 2.4),using a calibrated display and a color-managed output, and deliver files in that color/gamma space, and hope for the best. You can't control the world, and bad monitors are out there.
marc wielage, csi • VP/color & workflow • chroma | hollywood
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Jim Simon

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Re: Color grading when uploading to aggregator

PostSat Dec 02, 2023 3:36 pm

I favor Marc's answer as well. I watch everything on a properly calibrated display in my home theater. Watching video anywhere else is...barbaric! :o

So, do it correctly. Export it correctly. And those of us who watch it correctly will thank you. ;)
My Biases:

You NEED training.
You NEED a desktop.
You NEED a calibrated (non-computer) display.
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Zack_W

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Re: Color grading when uploading to aggregator

PostTue Dec 05, 2023 10:53 pm

Marc, thanks for your reply (and for all the extremely helpful and informative messages you post throughout this forum)!

I'm very aware that it's essential to work on a properly calibrated monitor. As I mentioned, I'm using a hardware calibrated monitor set to Rec.709 2.4 gamma, fed by the output of a UltraStudio Monitor 3G box. I also have the brightness set to 100 cd/m2, work in a darkened room, etc. So far so good, I think.

The reason I'm not using color management (just plain unmanaged DaVinci YRGB) is that all of the source footage is from a single camera, a Sony RX100 stills camera (long story, don't ask) that recorded 8-bit AVCHD. The camera was set to sRGB, though it's not clear if video also recorded to this space. In any case, there were certainly no LUTS for color management to work with. I de-interlaced the footage and converted it to ProRes 422HQ with Hybrid prior to editing. From my reading of the chapter on color management in the Resolve manual, my understanding is that color management is not helpful in this kind of situation. But please let me know if I'm wrong.

I also understand that people will watch online videos on wildly out-of-whack screens in all sorts of different lighting environments, and the best I can do is grade on a properly calibrated monitor and assume this will minimize the degree to which the wide variety of viewing systems out there will distort the video's appearance.

But there is still one other problem which it seems we have some ability to address. A large chunk of online viewers will be watching on an application or browser that is subject to Apple color management; the rest of the viewers will not. A video viewed on an Apple color managed application will generally appear to have a different gamma then when it is viewed on a non-Apple platform. I've been following the discussion about NCLC tags in the ongoing "Final Explanation of Gamma and Color Shift Problems," and I'm also intrigued by the video from FilmLight's Daniele Siragusano (embedded in the "Color Management for Video Editors" article you linked to) that suggests editing the tag to 1-13-1.

Regardless, I'm still trying to figure out my original question. Whatever solution I end up using for addressing the gamma shift issue, whether it's editing the NCLC tags or adjusting the grade or something else, would that also apply to a video file I submit to a streaming aggregator or do aggregators have their own ways of dealing with the gamma shift issue?
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rNeil H

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Re: Color grading when uploading to aggregator

PostWed Dec 06, 2023 6:48 am

You do walk around the issue pretty decently there. Realistically, the problem is how the file is displayed by different screens. The NCLC tag, as a bit of metadata in the file header, can give your intention, *if* ... the app or screen pays attention to or follows that instruction.

But as so oft noted, including in the other thread you mentioned, apps, browsers, players, and online services will do their own thing no matter what you do.

It's interesting and sorta useful to see what *they* do. But in the end, we don't seem to have much control out "there" ... and as the old saying goes, "You can't fix gramma's green TV."

Maddening, all kinds of frustrating, and still true.





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