Importing Music from CDs

The first step in stocking your digital jukebox will probably involve bringing in music from your audio CDs. Apple calls this process importing, but most digital music fans refer to it as ripping (from the Latin, meaning "to rip off").

Whatever you call this process, iTunes is good at it. Insert a compact disc into your Mac's CD drive, and iTunes launches, connects to the Internet, and retrieves the name of the CD and its tracks. Click the Import CD button, and iTunes converts the CD's contents into digital music files that are stored on your Mac's hard drive.

That's the big picture. You can create a vast digital music library with iTunes without having to know any more than that. But iTunes has several features that give you more control over the ripping process. You can, for example, specify that iTunes import only certain songsno need to waste disk space by storing songs you don't like.

And as I describe on the following pages, you can choose to store your digital music library in a variety of formats, each with its own advantages and drawbacks. But don't feel obligated to delve into those details if you don't want to. Feel free to skip on to page 30 after you've mastered the ripping two-step: insert CD, click Import CD.

Tip

To uncheck all tracks, press while clicking on a track's check box

Joining Tracks to Eliminate Gaps

In some cases, you might not want a gap of silence between songs. For example, the songs on a CD might be composed so that one flows seamlessly into the next.

You can prevent gaps between two or more songs by importing the songs as joined tracks. Select the tracks, then choose Join CD Tracks from the Advanced menu. iTunes will import the tracks as one file. If you decide to not join the tracks after all, choose Unjoin CD Tracks from the Advanced menu.

Note that you can't join tracks that you've already imported.

How iTunes Retrieves Track Names

Back in the late 1970s, when the compact disc standard was being developed, no one foresaw the iLife era. As a result, the developers of the CD standard didn't create a way for CDs to store artist, album, and track names.

So how can iTunes retrieve this information? The answer lies in the fact that no two audio CDs are the exact same length. A CD is comprised of a specific number of blocks, each of which is one seventy-fifth of a second long. You might say that every CD has its own unique digital fingerprint.

In 1996, some clever programmers in Berkeley, California, realized they could create a database that would link these fingerprints to specific information. The compact disc database, or CDDB, was born. Soon, CDDB spawned a company, Gracenote, which provides disc-lookup features to Apple and other companies that have digital music products.

When you insert a CD, iTunes calculates its digital fingerprint and then sends it over the Internet to Gracenote's server. If Gracenote finds a match, it transmits the corresponding information back to iTunes, which displays it.

Just how big is Gracenote's database? As of 2006, it contained more than 4 million CDs, representing over 55 million songs. That's even bigger than my iTunes library.

Incidentally, the audio CD specification now contains provisions for storing track information on a CD. It's called "CD-Text," but its support in the music industry is spotty. Sony has been including CD-Text information on its releases for several years, but many record labels don't support it.

Power Ripping: Changing CD Insert Preferences