Where do people get Final Fantasy VII: Advent Children footage to make YouTube videos?

In order to make YouTube videos on Windows Movie Maker, you need to get your videos from SOMEWHERE. Some people use capture devices to get their footage, others via camera/other. It IS possible to download the Advent Children movie on the internet, although in SOME cases it takes DAYS to download it - if not hours. So, posing the question again, how can there be SO MANY Advent Children videos made by people around the world on YouTube? How could they have gotten their footage?