Difference in video brightness/contrast across viewer applications

Question

I am using FCP->Color>FCP roundtrip to grade Red footage. After I grade the clips in Color and send them back to FCP, I see a difference in brightness/contrast of the graded clips when playing in FCP. And when I export the final output to quicktime and play it in quicktime player, I see further difference in brightness and contrast. Essentially the clips appear darker when played in QT player. Now I am confused as to which application is showing the correct brightness/gamma level? Is there a way to make all the applications play the video at same/true brightness/gamma? Any insights would be highly appreciate. Thanks!
-Pranab

Answer 1

There is a distinction between PCIe-based GPUs and I/O cards that you have to be aware of. COLOR's user interface, render/scopes and output are split between the two. A graphics processor handles the user interface (PCIe is better, application won't run on on-board integrated or AGP), and actual grade values for judgement are based on a PCIe HD-SDI I/O card like AJA Kona3, or Blackmagic (Intensity?) which are NOT graphics cards, they are video interfaces.
For GPUs, if the application is running, that's a good indicator. However, preferred cards have been evolving over the past 5 years. My first system was configured with a Quadro 4500FX which was a total waste of money. I deliberately chose an ATI X1900XT for the next tower, which was a significant improvement. My third MacPro is running fine with the default ATI 2600HD, which is as plain vanilla as you can get. Some users report speed advantages with the newer 4870 series, but I fail to see significant differences -- COLOR in its current delivery will never deliver "real-time" preview playback on any card, and it still takes a very long time to render, in comparison with some other grade offerings. Fourth machine, I'm still deciding, but it would be great if Apple got the FX4000 thing happening, and I'll get to that.
Nvidia does suffer from some bit-depth processing issues in that it does not directly support 10-bit codecs, but can be switched into the more intensive "float" mode. It also has some other transient issues.
Looking outside Apple COLOR, consider that Blackmagic Resolve ("DaVinci") is predicated entirely on nVidia's CUDA-processing technology and is restricted to implementation on 2 or 3 very specific cards, as opposed to the FCP-centred, but ATI/AJA-leaning Apple solution, which, although somewhat restricted, is 90% more likely to run on almost anything PCIe that you can stick into a MacPro. However, the color science and cross-platform (AVID support, for example) that DaVinci offers makes it very tempting, and that's why I'm paying a lot more attention to nVidia these days.
If you are looking for HDSDI PCIe cards, then AJA, with IO, Kona3, and so on definitely has the edge and can extend capabilities up to and beyond 2K processing, but many users select other solutions that suit their individual needs -- not everyone delivers theatrical Digital Cinema or needs to.
jPo