Re: [Avid-L2] IMF DolbyVision Metadata version mismatch in Resolve?

Please see my comments below:

On Feb 22, 2021, at 3:38 PM, John Moore <bigfish@pacbell.net> wrote:

From the CPL in the imf the version that created the IMF:
<Creator>Blackmagic Design DaVinci Resolve Studio 16.2.5.015</Creator>

I would not be surprised if that bug was fixed since that version. 

I am using Resolve Studio 16.2.7.  I'm milking the life out of my Nvidia 980Ti and two TitanX GPUs but the end is near with compatibility issues.

I understand. I believe your limitation is the compatibility between your Mac OS and the nVidia cards (Metal vs CUDA)

Per your info the timeline color setting tell Resolve's controls what to expect for tonal ranges.  In HDR class the instructor's company ColourLab has an HDR plugin that you put on as a timeline node and it will take a Rec 709 timeline and content map it to various HDR outputs.  This keeps the lift, gamma, gain behaving in a more natural way for the operator. 

I am familiar with ColourLab plugin (Dado Valentic's child) but you don't have to use it in order to take advantage of the many color management workflows in Resolve.

I need to find a flow chart of exactly how Resolve handles the various levels and conversions so I can play along better.  I know it attempts to map everything to full range and then limits the output based on codec or a manual setting of Data vs. Video a.k.a Full Range vs. Legal.  I have found that in Auto Clip attribute Resolve sometimes makes some wrong choices.

In HDR it is always Full data levels, ideally 12-bits. If you are talking about the settings of Data levels: Auto in the DELIVERY page, what you may have encountered are issues with different file formats / codecs. Tagging is not always done correctly, ProRes being a notorious example.

What would be the proper way to choose a timeline setting? 

To me it all depends on the project workflow (from production to post) and obviously the type of shows / programs you are working with. The cameras also might impact your choice. Your delivery requirements will also be important to know before hand. Depending on your editing path to finishing, if you are doing a roundtrip from AVID or if you are finishing in Resolve will also impact your choice.

I would assume you would pick the most common media in the timeline but then there must be a battle between a show shot in V-log and you get Rec 709 Graphics.

Working with LOG format, I would strongly consider an ACES workflow, especially if you have all the cameras IDT available (most professional cameras do). From editing (dailies/offline) to color grading, it might bring you closer to the finishing quicker if well implemented.

It's all these little steps that I'm trying to understand better so I can better trouble shoot issues that come up.

If you just need to troubleshoot a master in DaVinci Resolve, I would setup a simple display referred workflow using DaVinci YRGB Color science. Make sure the input color space for the master file (in the MEDIA page) is correct. Same for your output color space/gamma (your timeline), and match the settings to your reference monitor.Then you should be set to check your master. In that scenario I would not use a Color managed workflow (scene referred).

I'm just tinkering with this project and I got an HDR class    from FxPHD that I'm going to get into.  Hopefully it will dislodge some of the tar built up in my ears.  It's tough  being an Dinosaur who feels more comfortable with SCH and a V1 pulse than the endless format chasing in today's world.  Oh well gotta grow or go.

I agree with you… learning is the way to go!

David Baud

Colorist & Finishing Editor

david at kosmos-productions.com

Hi John,

 

Let me try to answer some of your questions.

First do you know which version of DaVinci Resolve they used for outputting the IMF you are having some issues with?

 

My responses below in the text:

 

On Feb 20, 2021, at 11:25 PM, John Moore <bigfish@pacbell.net> wrote:

 I am running with separate color space and gamma checked because during my HDR IMF onboarding for Netflix without that checked and set to P3 and ST 2084 1000 Nits I would end up with approx half video level when exporting an IMF. 

 

Again which version of Resolve are we talking about?

 

Netflix Tech support gave me a tutorial video that showed I need to use separate color space and gamma to overcome what appears to be a bug in Resolve.  Here is a link Netflix Tech gave me to guide in setting up the project.  Here is a video

 

In the video I see version 15! By the end of February, version 17 should become official, but so far I found the beta version stable. Just to let you know, BMD has made great progress in the implementation of Dolby Vison HDR since v15.

I'm not sure when separating the color space and gamma what difference setting the gamma to 2084 or 2084 1000 Nits does.

 

For Dolby Vision HDR, regarding the gamma, your are concerned with PQ settings (defined by ST2084). You should match the intended output (your maximum luminance display). Usually 1,000 nits or higher. (i.e ST2084 1000 nits) When grading for Dolby Vision HDR you have to define your maximum luminance output. It will be encoded in the metadata, along with any other trims that are required for your delivery.  Usually the studios will have specific specs that they want you to follow.

I see no change in output to my HDR LG OLED and my Target Display PVM-2541 Sony.

 

When working on a Dolby Vision HDR program, you need to make sure to match your Resolve settings with your display settings. If your display is set to receive a BT 2020 ST 2084 @ 1000 nits video signal, make sure your Resolve Color Management project settings is set to the same. If your display is set for P3 D65 and Resolve settings is set to Rec. 2020, you will have a mismatch.

I'm not really clear on what setting the timeline color space and gamma does to the actual video essence.

Is it correct that setting the timeline color space and gamma tell the rest of the Resolve color path how to transform the signal to other target color spaces and gamma.  If I see no change when togging from gamma 2084 to 2084-1000 Nits is that because there are no color transforms in the rest of the food chain?  At it's core I'm wondering what setting the timeline color space and gamma does to image processing.

 

In Resolve, if you choose to work in DaVinci YRGB Color Managed workflow (scene referred) the timeline color space can be set differently than your output color space. You may choose to do so for different reasons. Following I believe are the main reasons:

 

. Down the road, you may want to make different masters with different color spaces. If your timeline is set with a wider color space than your output you will be able to take advantage of a wider palette without having to redo your color grading for future delivery. You just switch to your desired color output and create your new master.

 

. From a colorist point of view, and depending on the control surface you are using, some color spaces will feel more natural to manipulate when using some of the Resolve tools. A good example is when working in ACES color encoding. You will notice that your lift-gamma-gain tools are responding quite differently than when working in a Rec. 709 workspace. With version 17, Resolve introduced a new option "use color space aware grading tools" to help compensate for that different experience grading in a wide ranges of color spaces.

 

When working in a scene referred color management workflow (a.k.a Color Science = DaVinci YRGB Color Managed) changing the timeline color space will not affect the color space output. It will just change your experience in grading footage.

 

When working in a display referred color management workflow (DaVinci YRGB color science) , essentially your display and timeline color space are the same, so whatever you select there will be the same and affect your timeline and output.

 

Attached is a screen grab of the color management settings of a Dolby Vision HDR project I was involved. This is with version Resolve version 17 beta 8.

 

I hope this help,

 

David Baud

Colorist & Finishing Editor

david at kosmos-productions.com