There were some questions about this same issue, but I did not find an answer. I have two simple layers. A simple video (.mov) with a white background. Then I have another layer on top of that, a white box graphic. If I export that, everything is fine. QuickTime Player and VLC plays both whites quite gray, other players play them white. But fine so far. However, when I use Fast Color Corrector for the bottom video layer to make it just a bit more white (overexposuring it evenly), horrible thing happens.
Now after export QuickTime Player shows two totally different whites, the very white background and the box is very gray in comparison.
What do I do to fix this? Very strange. Could not find any gamut / color interpretation functions to fix this. There must be a solution?