How to (mostly) Fix RGB Gamut Excursions in Software

Series	Rethinking Saturation in DaVinci Resolve

Part 2: Rethinking Saturation in DaVinci Resolve

How would you like to spend a week color correcting a show that’s been in production and post-production for 8 months—only to have it rejected by a broadcast, cable or internet network?

Just when your client thinks they’ve made it to the finish line, the line judge throws a Red Card and puts their show on the bench… and it’s your fault! If you’ve been running DaVinci Resolve with ‘Broadcast Safe’ enabled, and you’ve been managing your overall saturation levels—then the likely culprit for your rejection? RGB Gamut excursions.

Dealing with RGB Gamut errors can be a nightmare.

RGB Gamut errors are difficult to identify and very hard for post-production software to manage. Here on Mixing Light, we’ve talked about this problem many times:

RGB Gamut Errors: Robbie talks about the overall problem and a few strategies for dealing with these errors
Legalizing Video Parts 1-6: Robbie and I tackle how to legalize in Speedgrade, PremierePro, DaVinci Resolve and using Hardware Legalizers. The link I’ve provided takes you to the part of the series where I talk about DIY Legalization. Once there, just above the headline of that Insight are the links to the rest of that Series—including, how to legalize with the Harris DL-860 that I talk about in this Insight
From the Mailbag—Legalizing without a Legalizer: Robbie, Dan and I chat about our legalization strategies in this roundtable discussion.

In this Insight, I rethink some of the tools we can use for legalization in Resolve.

I’ll also echo some key points in our earlier legalization videos, including how you can guess if you’ll have an RGB Gamut error by using the Parade Scopes in DaVinci Resolve.

For me, the key is to use two scopes provided by Divergent Media’s Scopebox. If you want to learn how I’ve set up my scopes, here’s my Scopebox overview video. I’ve since made a few modifications, but my basic setup is still the same.

Enjoy!

-pi

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Comments

Creator

Discussion
August 13, 2016 at 12:02 pm #33443

Patrick Inhofer
Keymaster

This is the discussion thread for the Insight: How to Fix RGB Gamut Excursions with Software (mostly)
Creator

Discussion

Nurali Kushkov
Member

August 14, 2016 at 4:02 pm

Thanks Patrick, great insight!
I thought it was interesting when you used soft clip you went per channel, I would probably go with linked channels and maybe in that case won’t have to desaturate shadows?
Don’t know, would have to look at the image to tell 🙂
Thanks again!
Patrick Inhofer
Guest

August 15, 2016 at 8:38 am

Actually, normally I would lock all three channels. But sometimes I don’t, especially the blue channel. Often you can pull that up and end up with a more natural looking image.
Colin Travers
Member

August 16, 2016 at 7:11 pm

Great insight, thanks Patrick!
Patrick Inhofer
Guest

August 16, 2016 at 7:33 pm

Thanks Colin!
Greg Greenhaw
Member

August 17, 2016 at 7:33 pm

So this the “display broadcast safe exceptions” option in resolve inaccurate?
Orash Rahnema
Member

August 31, 2016 at 1:50 pm

Hi patrick,
what about using the actual low&hi level clip in the softclip curves?
By moving it ever so slightly would’t you clip the problematic pixels leaving the black level where you initially wanted it?
Patrick Inhofer
Guest

September 1, 2016 at 10:53 am

It’s not that the option isn’t accurate… it’s not comprehensive enough. It fixes what it says it’ll fix but if you’re delivering to a distributor, it’s doesn’t go far enough.
Patrick Inhofer
Guest

September 1, 2016 at 10:56 am

The softclip will lift blacks, especially if you’ve got large excursions. If I can, I’d rather desaturate those blacks first to see if it’ll fix the problem. If not, then I’ll go to the Hi / Lo softclips and use those.

One thing I didn’t mention in this Insight (but has been covered in other Insights dealing with the Hard and Soft Clips) is using the Hard Clip and setting it one or two IRE above zero black, which can also help (but is not a guarantee).
p_glaningeryahoo-de
Member

April 3, 2017 at 1:43 pm

So with this final fixes presented in this video done, this Clip should be exported as “Data Levels” not “Video Levels” and still be broadcast save? Am I right?
Patrick Inhofer
Guest

April 3, 2017 at 2:13 pm

Correct. Technically, this has nothing to do with ‘Broadcast Safe’. It’s about how the grayscale bit values get represented within the ‘bit container’ of the file that gets written to disk – so that other apps read those bit values correctly.
justinjustinstephenson-com
Member

July 28, 2017 at 12:55 am

The video in the insight is unavailable. “Video URL cannot be accessed….blah blah”
Robbie Carman
Guest

July 28, 2017 at 10:55 am

hey justin – sorry about that, a causality of our switch over to ML 2.0 Should be working now.
justinjustinstephenson-com
Member

July 28, 2017 at 3:57 pm

Thanks! Brilliant. I often use lum vs sat and sat vs sat creatively – nice to see that these same tools can be used to fix gamut excursions. Super useful insight.
Author

Replies

Author

Patrick Inhofer

Insight # ML 0506

Type Video

Duration 13:13

Skill Level Advanced

Skills DaVinci Resolve Theory

Categories Legalization Scopes Theory Workflow

Series Rethinking Saturation in DaVinci Resolve

How to Fix RGB Gamut Excursions with Software (mostly)