FCP Color/Luminance Shift on Export

Posted by LyleHolmes 
FCP Color/Luminance Shift on Export
March 11, 2011 03:09PM
I know this has been covered, but I'm struggling to find a solution and it's kicking our butts for over a week.

When exporting a clip with either QT Movie or Conversion, the resulting background white is 246, 246, 246 and not 255, 255, 255. This is a web project and the background of the video needs to match the webpage; designer used 255 for the webpage.

We've done dozens of these types of videos but for some reason it's just now become a problem. (It may have been a problem and we just didn't realize it until we had to match the white.)

V1 has a matte > solid color (tried using a jpeg and tiff ... same result) RGB/254 or HSB/0,0,100
V2 has a video with an Alpha channel

The export works and plays fine, but the white shifts so you get this grey box around the performer.

Tried RGB and YUV; animation codec, ProRes, etc.

Timeline looks fine; the problem is only on the export.

Thanks for your help.
Re: FCP Color/Luminance Shift on Export
March 11, 2011 03:29PM
Work in a Prores timeline and render before exporting. What codec is your source.

Re: FCP Color/Luminance Shift on Export
March 11, 2011 04:56PM
Brilliant. You're spot on.

The footage is DVCPRO HD 1080p30.
We have one sequence with the original footage. Pull a key, color correct, etc. this sequence.
That first sequence is nested inside another sequence. This second sequence is set to the size of the final output (in this case 200x416). This sequence also has the white matte/solid color.

So, we created two new sequences with ProRes 422 as you suggested. Rendered both. And exported to QT Conversion using H.264. Bingo.

Man, it feels good to have that issue resolved. Wish I could buy you a virtual beer.

Re: FCP Color/Luminance Shift on Export
March 11, 2011 05:49PM
Glad you had the issue resolved. Not sure why you had a gamma shift with DvcproHD. I'm guessing the oddball frame size was set to DvcproHD, and DvcproHD was not designed for that oddball frame size. One thing that prevented gamma shifts on export was the rendering, as Quicktime Conversion usually works off rendered files, so if the color was off, you'll see it in the renders.

How would I do it different? I would export> quicktime movie, set to current setting and encode in Compressor. I may even decide to do the cropping in Compressor, and edit with a matte layer to know where the borders are and what gets cropped off. The quality of Quicktime Conversion isn't as good as FCP's batch export or encoding in Compressor. Also, because export>quicktime movie copies frames from the rendered footage or from the source files if your footage does not require rendering, so you would not encounter issues with luminance shifts on export.

Re: FCP Color/Luminance Shift on Export
March 11, 2011 06:38PM
I'm not at my desk...cellphone.
Thanks for the great help. I'll digest it when Im back in front of my computer.
I sent you an email via your blog/website.
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