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Prores4444 goes illegal on render!
Anyone getting this?
Make some white text with a drop shadow on black in Motion and render out as Prores 4444 with Alpha.
Drop onto a seq on trk 2 in a timesline thats codec is Prores. All good.
Force render
Everything is exactly the same apart from the text which is now illegal looking at external scopes!
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7 Replies
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ProRes 4444 is an RGB codec…not a Y’CbCr codec.
(Most “4:4:4” codecs are RGB, there are very few Y’CbCr schemes that run a full sample on all color channels.)
As with most RGB video…the color gamut is really meant for compositing or non-television video workflows (as in film or feature post production).
Most RGB codecs operate with values that are illegal in Y’CbCr color space (the space you are measuring in with your external WFM and Vectorscope), just as Y’CbCr generates values that are illegal in most RGB color gamuts.
TimK,
Director, Consultant
Kolb Productions, -
What color is your text? If it’s 100% white, then it’s supposed to be illegal. Anything above 92% white is illegal.
Arnie
Post production is not an afterthought!
https://www.arniepix.com/ -
What alpha type did you render and what is FCP showing?
Did you modify the gamma correction in the QT prefs dialog in Motion?
What bit depth is your Motion project?
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Thanks for the replies everyone. When I get into the office I’ll get the specs on the motion proj.
ProRes4444 is not RGB according to Apples whitepaper ( from what I could make of it :-/)
Txt is pure white. It’s over 100 from what I’m seeing. It’s ONLY over 100 once rendered.
If 4444 is RGB why would Apple do so for an application thats limited to 8bit in RGB processing?
s
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From whitepaper-
Apple ProRes 4444 fully supports 4:4:4 image sources, from either RGB or Y’CBCR color spaces. The fourth “4” means that Apple ProRes 4444 can also carry a unique alpha-channel sample for every pixel location. Apple ProRes 4444 is intended to support 4:4:4:4 RGB+Alpha sources exported from computer graphics applications such as Motion, as well as 4:4:4 video sources from high-end devices such as dual-link HDCAM-SR.
Never says it RGB or Y’CBCR :-/ can be both ?
Any codec can support both.. you just convert to it. What it actually is would be nice. Can it be either? :-/
s
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Yes…I’m familiar with the meaning behind the numbers.
ProRes 4:4:4:4 can support both per Apple, but since Y’CbCr carries so much of the image material in the Y channel, it’s very unusual to see anyone use full sample for it. You CAN of course…but what you’d actually gain over 4:2:2:4, is pretty slight. Typically a full 4:4:4 sample is RGB.
In your case, I suspect that movie inspector could look at your clip and tell you what you have…then you’d know.
TimK,
Director, Consultant
Kolb Productions, -
[Simon Blackledge] “Txt is pure white.”
Then that’s why your text it illegal. This is not a bug in FCP, it’s common to any graphics or video app. If you use pure 100% white, that’s illegal for broadcast. Legal white is around 92%.
Arnie
Post production is not an afterthought!
https://www.arniepix.com/
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