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keep existing -10ire qt through afx?
I managed to get a deck to make -10ire “superblack” and capture that into FCP via blackmagic. When I bring it into AFX CS3, it always renders out at 0ire in qt. Does anybody know how to do this? I need to put some graphics over superblack and FCP renders the alpha soft, so I get a soft edge which won’t do for a 1 bit luma key…
Joe Gill
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4 Replies
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After Effects processes internally as RGB for which black is 0 (of the 0 to 255 8 bit values). Final Cut (and all instances of YCrCb video) put black at 16 (again, of the 0 to 255 8 bit values). That is, an 8 bit value of 16 equals 0 IRE.
Is your goal output to tape graphics over super black? If so, have you confirmed that superblack is preserved on output?
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I would like to build the gfx over the superblack in afx, as fcp introduces errors in the application of the aplha. If I can do the whole magilla in afx and render from FCP, I’m golden. I can get superblack into, through and out of FCP, but AFX is styming my efforts…
Joe Gill
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I can make this work in an Avid. In AE pre-comp your graphics build and place it over black in another comp. Then apply a levels effect to the pre-comp, set output black to 16 and output white to 235. Render out to Animation codec. Import this into an Avid while setting the source as 601/709 (rather than RGB, which it is). The conversion on import will restore the white and black points. Since the background black wasn’t altered by the levels adjust, it gets pushed down to the bottom (-10 IRE).
Following the same logic but bringing the clip into Final Cut (regardless of the codec it was rendered to) doesn’t work as it is not possible to push black below 0 IRE. It simply clips at that point. Perhaps a third party color corrector might allow this?
As AE processes in RGB, there simply isn’t any black less than black. Blacker than black and whiter than white (which FCP does allow) are built into video standards (analog and digital) as a safety margin.
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