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Problem Freeze Frames with Alphas

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redexit
Problem Freeze Frames with Alphas
on Jan 15, 2007 at 1:37:45 pm


Using a Kona LHe on quad, 10.4.8 and FCP 5.1.2

When performing a freeze frame on a graphic (created in AE 7.0) that has alpha attached, the opacity of the alpha
changes when frozen. There is a 3-5% shift in luminance between the original graphic and the freeze frame of the graphic.
I assumed this to be a AE related setting but I get no such problem whilst doing the same edit, with the same file
on a similar system with a Decklink extreme. Is there a set up I'm missing for the Kona??

Any help appreciated


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JeremyG
Re: Problem Freeze Frames with Alphas
on Jan 15, 2007 at 3:27:51 pm

Are you making the freeze frame within FCP?

How are you making it?

Have you tried exporting a still?

Can you make the freeze frame in AE?

Is the alpha interpreted correctly within FCP (straight or black)?


Jeremy


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redexit
Re: Problem Freeze Frames with Alphas
on Jan 15, 2007 at 8:16:48 pm


Jeremy

Freeze is created in FCP with 'Make Freeze frame'

The alpha is set to straight.

I can make the freeze in AE
but I do a fair amount of these graphic items and they need a 10sec hold and
rendering out takes a fair while longer in AE.

Thanks
Neil


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JeremyG
Re: Problem Freeze Frames with Alphas
on Jan 15, 2007 at 8:27:35 pm

Export a still from AE with an alpha. Much better quality.


Jeremy


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redexit
Re: Problem Freeze Frames with Alphas
on Jan 15, 2007 at 9:15:38 pm


Thanks.

Doesn't explain why I have no problems with freezes using the Decklink card though.
Any theories??


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JeremyG
Re: Problem Freeze Frames with Alphas
on Jan 15, 2007 at 10:43:50 pm

I think decklinks and aja cards handle gamma differently. AJA is WYSIWYG and Decklinks try and compensate.

That's my theory.

Jeremy


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redexit
Re: Problem Freeze Frames with Alphas
on Jan 17, 2007 at 8:03:28 pm

I have found the solution. Working in 8 bit, my video processing
was selected to be 'Render in 8 bit YUV' which seems sensible.

The problem with the freeze frames disappears when I select
'Render all YUV material in high precision YUV'


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