[Avid-L2] Re: OT: FCP and color levels

> Job ter Burg wrote:
> Most footage I get from video cameras have levels between 16 and 255 (using
> some of the headroom for the top whites). What happens, does FCP just cut
> these off?

FCP will pass the superwhite without clipping. It's the stuff at the bottom (0-16) that tends to get clipped if any rendering is involved. For example, the FCP color bars have a "blacker-than-black" pluge. If you add anything over the bars that causes a render (like a logo or text or a bug), then the pluge will be clipped when the sequence is rendered. If you have superwhites, some rendering causes clipping and some doesn't. Not all effects process the same way, since some (like a dissolve) are legacy code. I believe this also varies with the render process settings. Stu Maschwitz has written about this on ProLost in reference to the Colorista plug-in:

http://prolost.com/blog/2008/1/26/colorista-clips-no-more.html

> The most common workflow for them is to play the sequence back from
> MC-Nitris-DX (so the Nitris DX does the upscaling to HD), then capture the
> Nitris DX HDSDI output into the BMD-FC system....
> .....The student in question followed the suggested path (Nitris DX -> HDSDI ->
> FCP-BMD) and subsequently tried to compare the result of that process to the
> unscaled QT he had received from the color correction house, and then a lot
> of confusion occurred.

First of all, how did the grading house generate their QT? Did you import the QT into MC? What color mapping did you use? Do you mean that you are importing the QT into MC and then comparing the MC->FCP result to the original QT natively inside FCP? If so, it's unlikely that this will match up unless you are comparing both on a broadcast monitor/scope via HD-SDI. Also if the file is ProRes, you might also get different results compared with uncompressed, since ProRes has an automatic gamma correction function as part of its encoding parameters.

Here's a little experiment I ran:

http://digitalfilms.wordpress.com/2010/02/21/canon-5d-avid-fcp-roundtrip/

- Oliver

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