iMovie '09 & iDVD: The Missing Manual

Aspect Ratios: The Missing Manual

Aspect ratio is an annoying geek term for shape of the movie frame. Having to learn about aspect ratios is an unfortunate requirement if you're going to master video editing.

A standard 1980 TV set's screen isn't the same shape as a movie screen. The TV is almost square but the movie is wide and short. They have different aspect ratios (see Figure 2-7).

Standard TV sets have a 4:3 aspect ratio. Those are the horizontal:vertical proportions. So if your screen is 4 feet wide, it's 3 feet high.

Figure 2-7. iMovie offers you a choice of three aspect ratios: Standard (like a traditional TV), iPhone (which has a nonstandard screen shape), or Widescreen (like a high-def TV). You can always change your mind later.

High-def TV screens, on the other hand, are 16:9. If the width is 16 feet wide, then the height is 9 feet (and you have a heck of a big TV).

Note

Weirdly, 16:9 is not the standard aspect ratio for Hollywood movies! Those are usually 1.85:1 or 2.35:1. (Don't ask why movie aspect ratios always have 1 in the denominator. Nobody ever accused the video industry of being consistent.)

Believe it or not, those aren't even the only common aspect ratios. Consider the iPhone, which, of course, Apple hopes that everybody owns. Its screen is 3:2!

Every time you create a new project, iMovie asks you, "What aspect ratio would you like, O Master?"

If the result will play ...