For all you Nikon HDSLR shooters, this little fun fact may change your life. If you simply change the file extension of your clips before throwing them into premiere, they’ll actually play and not just stutter like you’re using an Apple G4 to edit hd video.
From the Adobe support site:
When you play or scrub through a sequence that contains a clip based on a movie from a Nikon D7000 camera, playback is not smooth.
Change the filename extension of the movie file from .mov to .mpg and reimport it.
Adobe Premiere Pro can natively decode some movies wrapped in QuickTime containers, without using QuickTime Player. Native decoding is much faster than going through the QuickTime component.
When Adobe Premiere Pro imports .mov files from a Nikon D7000 camera, it mistakenly thinks that it must use the QuickTime component for reading the file. By changing the filename extension to .mpg, you are telling Adobe Premiere Pro to use its native MPEG decoding component, which is much faster.