Whenever I import a video into imovie the movie appears to be screen tearing, even though when the actual file is played, no screen tearing is seen. I record gaming videos for my youtube channel, and those import fine, but when I export movies from an AVCHD file, and try to import those into imovie, it screen tears. The movies imported playback fine with no screen tearing, and is only present after importing them into imovie.