| Color to FCP, HD/SD question
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 | Color to FCP, HD/SD question
by Dane Cannon on May 11, 2011 at 1:05:59 pm |
I'm working on an SD sequence, brought it into Color, graded it, sent it back to FCP as ProResHQ 422 720x480. There is a massive image shift when I bring it back into Color. I've read about the gamma shift that existed prior to Leopard. I'm on 10.6 so I don't think that's the issue. I know that HD and SD are different color spaces. I'm using a 20" JVC monitor that was calibrated for HD. Before starting, I ran NTSC SD bars through it, and calibrated to them. When I went to set my output in color, the Matrox card I was using only would output in SD at 720x486. It tweaked the aspect ratio of the image a little (and I found it annoying), so I switched my output to 1080i. I thought, "My monitor will just be taking the SD image and blowing it up to fill the monitor screen, so what's the difference if I have Color upres the image as opposed to my monitor? So I lose the 1:1 function, at least it won't look stretched." I figured that I was already calibrated for SD, and my export in Color was set to SD, so it should be fine.
It's not.
Parades match. Vectorscopes do not. There is an increase in saturation that I suspect is a gamma issue. It seems that I can apply the saturation filter at -.33 and that matches it up pretty well, but obviously this is not the ideal workflow, nor do I think this is an accurate gamma fix. What did I do wrong here? I'm pretty sure now that it was setting my monitoring output to HD... but I thought I'd throw it out there. Equally important, what's the best way to fix it?
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• | | | |  | Re: Color to FCP, HD/SD question
by Joseph Owens on May 11, 2011 at 1:21:28 pm |
Is this an SDI feed to the JVC, or is it some VGA/DVI/RGB/Y'CbCr/HDMI GPU converter thingamajig? There is a difference between 608 and 709, and there are differences between digital and analog streams, and there are differences between GPU devices operating under ColorSync and I/O devices (Kona, Decklink), that do not.
So, at this point it would just be guesswork.
I don't know what a Matrox is supposed to do.
JPo
You mean "Old Ben"? Ben Kenobi?
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• | | | | | Re: Color to FCP, HD/SD question
by Dane Cannon on May 11, 2011 at 1:49:18 pm |
It's the Matrox MXO2 Mini connecting via YPbPr component.
This thread sounds a lot like the trouble I'm having, and it raises a good question. Is there some sort of filter that will automatically do the rec 709 to rec 601 conversion? This is perhaps wandering into the FCP realm, so I'll post over there...
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• | | | | | Re: Color to FCP, HD/SD question
by Joseph Owens on May 11, 2011 at 2:32:35 pm |
[Dane Cannon] "some sort of filter"
Its not a "filter" kind of proposition. Usually analog outputs have a "pedestal" black of 7.5 IRE where CCIR601 SD video is zero... that's for starters, and there are chromaticity and gamma differences, as well.
Its a "transform" that involves a matrixed-rescale, and is not a strictly linear process.
If you really want to know... http://www.poynton.com/PDFs/ColorFAQ.pdf
Or ask at the Apple Store, I'm sure they'll be able to help... probably only take a few minutes to explain.
jPo
You mean "Old Ben"? Ben Kenobi?
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• | | | | | Re: Color to FCP, HD/SD question
by Dane Cannon on May 11, 2011 at 3:07:01 pm |
I called the Apple Store, and strangely enough, their answer worked!
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• | | | | | Re: Color to FCP, HD/SD question
by Dane Cannon on May 11, 2011 at 3:25:42 pm |
Psyche (sp? sike?)! They just said "Make it a B&W film, call it an artistic choice." I understand that the 2 different spaces have different luma coefficients (though I admittedly couldn't really say what a luma coefficient was). Really though, let's say your footage is shot in HD. You grade in HD because you'll want to archive an HD master, but you also need to provide an SD copy for broadcast (I realize this isn't my situation). So...
http://www.poynton.com/papers/SMPTE_98_YYZ_Luma/index.html
Not a new issue. Is there some sort of industry standard "transformation" that is normally applied in these scenarios?
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• | | | | | Re: Color to FCP, HD/SD question
by Joseph Owens on May 11, 2011 at 8:48:30 pm |
[Dane Cannon] "Is there some sort of industry standard "transformation" that is normally applied in these scenarios?"
Yes. You play it out through a Kona card downconversion. that would be the Easy Button.
jPo
You mean "Old Ben"? Ben Kenobi?
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