It has come to my attention that Perian defaults to using PC-scale coefficients when doing its YUV-->RGB conversion. I have first noticed this with HuffYUV when comparing it to an uncompressed 4:2:2 source and now with playback of h.264 video. With both, video appears to be overly bright and washed out. See this thread: http://forum.doom9.org/showthread.php?t=143189
Upon disabling Perian, QuickTime uses its own h.264 decoder and displays the color correctly, matching the uncompressed 4:2:2 source perfectly.