Relatively new to iMovies, I created two MP4 files by editing digital camera home videos using iMovie. I had read that each hour of video translates into about 1GB of storage space as an MP4 file (and possibly up to 2GB per hour if HD). The MP4 files created (50 minutes & 93 minutes in length) both took up hard drive storage space equivalent to an average ratio of 9.1GB/video hour. I have many home videos (most VHS tapes) needing conversion and editing and I am concerned why the large amount of file space for these first two MP4's that I have created? Is there a relationship to the number of edited clips in the MP4 video file (ie. both have a large number with each 3-10 seconds in length)? Looking for a good resource for this question and possible more yet to be encountered.