Compressor source file preview different from QT?

When I open a file in Compressor 4.4.1 on my iMac Pro running High Sierra 10.13.4 the source video in the preview window looks nothing at all like the video does when I open it in Quicktime. It looks like there is a major gamma shift in the displayed clip before I apply any sort of output setting. It doesn't matter what format or color space it is, it's always significantly darker with contrast/color/saturation/etc differences. That makes the before/after split screen a guessing game as to what the output will look like depending on what changes I make in the Video Effect section. Is there some extra setting somewhere for Compressor that I'm missing?