MPEG2 and StreamClip
Some low end video cameras successfully record videos in .MOV or .AVI file formats, but using the MPEG2 codec. There's nothing wrong with that, except that many video editing Applications cannot directly edit, or even import, MPEG2 video.
The solution is to download and install MPEG Streamclip for Macintosh, and use it to convert your videos into an appropriate format.
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