Gamma shift upward

A

Antoine_Fabi

Well-known member
Hi,

We had to apply graphic work over a QuickTime Uncompressed 8 bit footage from Final Cut Pro.

The graphic work was done in After Effects.

The After Effect output was done using QuickTime Uncompressed 8 bit, the very same codec.

...but all the footage has a gamma shift ( upward ) of about 1.18 and a slightly increased color saturation...

What's wrong ?

thanks !
 
As an experiment, have you tried rendering to a non Quicktime format? Even just to a short TIF or JPG sequence to see if the issue still appears?
Might be worth a try, just to check if the issue is actually in the render or may just in QuickTime's display of the render.

I've heard of reports where QT improperly displays the gamma and color of H.264 encoded files. Never heard of the issue with Uncompressed though.
 
Hi Nick,

I'll try it.

Yeah...bizarre considering it is a Uncompressed file...

Even more bizarre is the fact that If i export Uncompressed 8-bit 4:2:2 from FCP and reimport it, there is NO gamma shift.

The gamma shift occurs only when i reimport a file that has been processed in After Effects...even if i use Uncompressed 8-bit as export setting.
 
Uncompressed shouldn't do that. I know Sorenson will mess with your levels, and make them a little darker. I've never had any problems going uncompressed.

hmm.


EDIT: Have you tried an .avi? It may be a quicktime issue, but for the life of me I can't find what. It would be intersting to see if you exported as .avi or .png sequence if you got the same kinds of results.

That's just damned odd. Normally when you export as quicktime you have the options of setting the "Filters" along with frame rate, frame size, and audio settings. Is it possible you are using a template in which there are some levels/brihtness adjustments in the Quicktime output options?

Are you creating the quicktime from Compositon>Make Movie, or are you creating it by going File>Export>Quicktime Movie? I have had problems with quicktime files seeming to lose resolution when going from making them from Composition>Make Movie which did not happen when I used File>Export.

Weird.
 
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