Help scaling mixed aspect ratios (16:9 & 2.4:1) from Resolve to DCP-o-matic?

[Odinmadmax]

Hi everyone,

I’m preparing a project for a cinema screening and I'm running into a frustrating scaling issue when moving from DaVinci Resolve into DCP-o-matic.

My Project Setup:

Roughly 80-90% of my original clips are in a 16:9 aspect ratio.

The remaining 10-20% are in a 2.4:1 aspect ratio.

The Problem:
I am having a really hard time getting the file to properly fill the container in DCP-o-matic. Whether I export from Resolve as 16:9 (with black bars for the 2.4:1 footage) or export as a 2.4:1 timeline, the imported file always shows up too small (windowboxed) within the DCP container.

My Questions:

What should my Timeline and Output Blanking/Resolution settings be in Resolve for a mixed-ratio project like this?

Once exported, which Container (Flat or Scope) and Scale settings should I be selecting in DCP-o-matic so the image fills the screen properly without the "postage stamp" effect?

I want the 16:9 footage to be as large as possible, with the 2.4:1 footage naturally letterboxing, but I'm clearly getting my container math wrong. Any advice on the proper workflow would be hugely appreciated! Thanks!

[IoannisSyrogiannis]

A similar matter was discussed here:
https://dcpomatic.com/forum/viewtopic.p ... 589#p13589

If I was you, I would fit the narrower (16:9) aspect ratio inside the wide (2,4:1, or 2,39:1, if Scope). That would give a sense of widening when changing to Scope.

Yet, that would need a Scope screen on the cinema. If the screen is Flat (1,85:1), the image would go from window-boxed to letterboxed and the whole trick wouldn't have the same effect.

If your goal is to give the sense that for that 10-20% the viewer's world (the picture) gets bigger, you need to set your project according to that, and pillar-box the 16:9 inside it.

If that is not your goal, or the cinema screen is Flat, you may consider your options.

In any case, you need to choose what the "big screen" will be and fit the other aspect ratio inside that.

Now, about "the Problem".
On the DCP menu, you may choose a Flat or a Scope container. If your timeline (and therefore your export) from DaVinci Resolve is 2,4:1, it goes without saying that you need to choose Scope. If it is 16:9, you need to choose Flat. Otherwise (if you put 2,4:1 inside Flat/1,85:1), you will face the problem you describe.

[dcpforever]

I would export a 1998*1080 (Flat) file from Resolve, so that DoM would not have to intervene. It is easier to control scaling and cropping in Resolve.
And without pillarboxing the 16:9 material, I would simply stretch it to the edge of the Flat, so that it would be cropped a little at the top and bottom. Some of the image is lost, of course, but in general it is difficult to notice. I hope that makes sense.
Then I would scale the 2.39 material to the edges of the Flat, which would be letterboxed, of course.
That way, you can control how the image will look and you won't have any problems with DoM.

[Carsten]

There is no single formally correct solution for such mixed aspect ratio material. It depends on your creative intention.

Do you want to widen the image when switching to scope - then pillarbox 16:9 in a scope container. Do you want to 'collapse' from the 16:9 to a 'narrower' scope aspect image, then use a flat container with the scope ar content appearing letterboxed in it.