XYZ Color Conversion & Scaler

[BravoZulu]

Hello,

Thank you again to Carl for this wonderful software and documentation

But, I have a doubt on the relationship between:
a) Tab "Content": "Scale to"
b) Tab "DCP": "Scaler"

In the Manual (P.21), I can read:
"Finally, the Scaler is the method that will be used to scale up your content to the required size for the DCP, if required.
"Bicubic" is a fine choice in most situations."

Because if I use "No scale" (Tab "Content") the "Scaler" (Tab "DCP") is always active. (The effect of the process, eg. "Bicubic" is visible in the preview).

There is therefore no possibility of obtaining only the conversion eg. "Rec. 709" to "XYZ" ?

And, where can I find more information about the options "Scaler" ?

Thank you in advance for your answers

Guy-Laurent

PS: Carl, I think the "Scale to" should be default: "No scale", not "Flat" !

[Tested version: DCP-o-matic 1.72.0 x64 - Win7U_SP1 x64]

[carl]

Because if I use "No scale" (Tab "Content") the "Scaler" (Tab "DCP") is always active. (The effect of the process, eg. "Bicubic" is visible in the preview). There is therefore no possibility of obtaining only the conversion eg. "Rec. 709" to "XYZ" ?

At the moment, with "No scale", the source will be converted to RGB and then XYZ. I'm not entirely sure what the scaler does when there is no resizing going on; I would have to test that.

The scalers available are from FFmpeg, and are described here.

PS: Carl, I think the "Scale to" should be default: "No scale", not "Flat" !

I suspect that's a matter of opinion You can set your preference in the "Default" tab of Preferences.

[BravoZulu]

Hello Carl,
Thank you for your comments and your great work.

I suspect that's a matter of opinion You can set your preference in the "Default" tab of Preferences.

By far the idea of imposing my opinion.

Further to our previous posts, is now added the concept of "Container".
In the "Preferences" > "Defaults" option "No Scale" does not exist!

This is the "Container" DCP size. Right? (Based on the size of the chip DLP).
(Normally - Projector Aspect Ratio: F = Flat (1.85:1), S = Scope (2.39:1), C = Full Container (1.90:1).


For me the confusion is that in the Menu Video "Scale to" uses the same configuration (default) "Container", with "No scale"... added.

Because if I use the 16:9, I do not want to use the full width of the Container, which distorts the image.
So I have to change it to "No scale". That's why I was talking about "default" (No scale).

I hope you understand, it's hard to explain, especially in English.
So, what is the reason for the mix of Container and Scale? (Maybe this type of conversion comes from DVD-o-matic I've never tried and seen).

Best regards
Guy-Laurent

[Carsten]

I also expressed my concerns about this to Carl recently. It doesn't harm having both options, but it is quite confusing. Admittedly, the scaling, masking/padding and aspect ratio handling is probably the most complex decision issue for, hmm, 'ordinary users'.

Usually, the comments below the config tab explain nicely what the program is actually doing. However it is now and why, I expect these options to change again at some point.

There is sort of a Catch22 with this program - it enables non-professional users to create media content for professional projection systems with their very specific presentation aspects, like variable masking, audio channel mapping, etc.

Yet, to make educated decisions about the various parameters, these users SHOULD be properly educated to be able to make the right decisions.

I do think that DVD-o-matic and DCP-o-matic so far did a fantastic job in the GUI to give as many explanations and hints towards chosen processing options and proper usage. As a matter of fact, this is the reason why I started using the program in favor of other existing tools. A one-stop-solution without any hidden or obscure 'automatic' best-guess processing.

But there is a certain limit to this. At some point, making the right decisions simply needs specific knowledge to be acquired beforehand (or by experience).

- Carsten