Final Cut Rendering Glitch

I noticed an interesting (read: incredibly annoying) glitch in Final Cut’s rendering today. I’m color correcting some commercials for Quiksilver. There’s a part where one portion of a shot cross dissolves into another. They are the same shot, but the first clip was rendered out of After Effects, and it’s cross dissolving into a clip that’s just the basic ProRes HQ shot. The shot originated on a Phantom HD, which shoots Cineon files that we convert to ProRes HQ before editing (or sending to After Effects). During the cross dissolve itself, the clip gets slightly brighter and the colors shift just a tiny bit. Then when the cross dissolve is over, the brightness and color shift back. It’s only during the cross dissolve itself. The first clip and the second clip are identical in color and brightness. The shift is only really noticeable on the canvas window. I can’t see it at all on the broadcast monitor (FSI 2450). I tried to change the render settings (high precision YUV, all RGB, everything), but it was always there after being rendered. When I export the timeline to a ProRes HQ Quicktime, it’s there also. If I take that ProRes HQ export and make an H.264 file for web use, the shift is there, but even more prominent than before. The only solution has been to check the “Recompress All Frames” box when I export the timeline to Quicktime. I’ve only done that a few times before because it takes a lot more time to export since it ignores all the render files in that sequence. But I’m going to do that all the time from now on. I didn’t even notice the shifts because they didn’t appear on the broadcast monitor. My client noticed them on the H.264 I sent, which isn’t good.

Moral of the story: Always check “Recompress All Frames” when exporting Quicktimes from Final Cut