I backed up my AVCHD to my external hardrive. I am concerned that I will not be able to access the format of the files once they are on the hardrive and no longer on my camera. When I want to import clips to iMovie, I have previously accessed them from the camera directly. I attempted to import them into iMovie from the external and iMovie did not recognize the files. How can I backup my movie files from my Canon HG20 to an external drive and still be able to access the files for viewing/editing on my computer.