I am also having a problem with h264 mp4 - a few minute clip that is supposed to be importing has been counting up time under the 'time remaining'. It isn't just changing the time estimated, it is actually counting up seconds. Quite strange, or is this intended behavior?
Also, somewhat unrelated, various "mpeg" files in a variety of codecs simply list as 'unknown'.
I am not sure if I am missing some component - I have the Matrox codecs and Quicktime.
I've been testing for about 3 hours. I tested PNG sequence, TGA import, DV AVI 29.97 fps Widescreen progressive and video captured with my Canon T2i Rebel 1920x1080 24fps which is H.264 MOV and I was able to import all without problems.
Running on a Sony Vaio Laptop, i7, 4GB RAM, external eSata 1TB drive, NVidia 512MB, QuickTime Pro