Chase Gordon
03-16-2008, 06:50 PM
While I grant this is perhaps an unusual situation and probably not a workflow to recommend to others, this is where I am today. I've cut my cut in Final Cut Pro using the QT proxies, but to get into the last phase of my post I need to be in Avid. The expensive (and better way) will be to bring in DPX files out of Scratch. The cheap way (which I'm attempting) is to bring in DNxHD files.
So I replaced the FCP QT plugin with the "Grade Quality" QT codec and rendered out the movie from FCP in ProRes HQ (noticeably better image quality, noticeably slower render, no way to play unrendered in FCP). Then I asked Compressor to transcode from ProRes to DNxHD 175 10 bit.
This transcode introduced a major gamma shift, at least as viewed on the Mac. The DNxHD movie is substantially lighter than the ProRes movie. Bringing up Apple's Digital Color Meter in Y'CbCr BT.709 space shows a shift in Y' from 55 to 76 (on a 256 scale) with no shift in Cb or Cr.
I bet it's no coincidence that this is the same gamma shift I see if I uncheck the "Enable Final Cut Studio color compatibility" option in the QT player. The thing is, unchecking that option not only makes the ProRes movie lighter (55 to 76), it makes the DNxHD movie lighter still (76 to 84, a double gamma shift).
Has anyone else hit this problem going from ProRes to DNxHD? Better yet, has anyone else solved it? Or is this only a problem because I'm viewing the DNxHD on the Mac and when I view them on the Avid all will be good?
So I replaced the FCP QT plugin with the "Grade Quality" QT codec and rendered out the movie from FCP in ProRes HQ (noticeably better image quality, noticeably slower render, no way to play unrendered in FCP). Then I asked Compressor to transcode from ProRes to DNxHD 175 10 bit.
This transcode introduced a major gamma shift, at least as viewed on the Mac. The DNxHD movie is substantially lighter than the ProRes movie. Bringing up Apple's Digital Color Meter in Y'CbCr BT.709 space shows a shift in Y' from 55 to 76 (on a 256 scale) with no shift in Cb or Cr.
I bet it's no coincidence that this is the same gamma shift I see if I uncheck the "Enable Final Cut Studio color compatibility" option in the QT player. The thing is, unchecking that option not only makes the ProRes movie lighter (55 to 76), it makes the DNxHD movie lighter still (76 to 84, a double gamma shift).
Has anyone else hit this problem going from ProRes to DNxHD? Better yet, has anyone else solved it? Or is this only a problem because I'm viewing the DNxHD on the Mac and when I view them on the Avid all will be good?