iMovie '09 & iDVD: The Missing Manual

Disk Images

Thanks to a handy iDVD feature, you can save your project as a computer file called a disk image.

You may have run into the disk-image (.dmg or .img) format before; it's a popular storage format for software you download. It's so popular because you get a single, self-contained file that contains many other files, arrayed inside exactly as though they're on a disk. When you open a disk-image file, in fact, it turns into a little hard-disk icon on your desktop, with all of its contents tucked inside.

Note

Don't confuse a disk image with a project archive; they're two very different beasts. A disk image is a virtual disk, a bit-for-bit copy of the data that would appear on an actual, physical DVD—it just happens to be stored on a hard drive rather than a DVD.

Project archives, in contrast, contain all the source project material used by iDVD. The only thing that can read or "play back" a project archive is iDVD itself.

To turn an iDVD project into a disk image, save it. Then, choose File → "Save as Disc Image" (Shift-⌘-R). Choose a file name (for example, Summer Fun.img) and a location, and then click Save. Now wait as iDVD compresses your movie data and saves it to disk. All of this takes just as long as an actual DVD burning, so now's your chance to catch up on some magazine reading.

When it's all over, you'll find a new .img icon—a disk image—on your desktop. Disk images are amazingly high-octane, cool stuff for two reasons:

• You don't have to burn a disc to watch your movies ...