Going Legit

MP3 had its day in the sun, symbolizing the freedom of digital music and the irresponsibility that inevitably comes with such freedom. However, it was not to last. If digital music were to become a mainstream medium to rival or even replace CDs, it could not be on the MP3 formatbecause as soon as a record label sold an MP3, the purchaser could immediately turn around and broadcast it onto the peer-to-peer file-sharing networks (which have never gone awayrather, they've merely become more and more sneaky and undetectable by the authorities). Some online digital music stores, such as MP3.com and eMusic.com, have attempted to make a business case on selling MP3s created by artists who don't care about piracy and are only interested in exposure to their fansbut those artists are relatively few and don't include any of the big-name stars whose music most listeners want to buy.

The answer finally came when Apple introduced Advanced Audio Coding (AAC), a digital music format similar to MP3 but protected with digital signatures that ensure that only a limited number of "authorized" computers can open or play a given file. This format was introduced at the same time as the iTunes Music Store, which opened the doors of legal music downloads for both Mac and Windows users. AAC files' Digital Rights Management (DRM) technology gave the record industry the assurance it needed that the products it sold would not be devalued through immediate and uncontrollable duplication.

Key Term

Digital Rights Management (DRM) Software algorithms that provide "copy protection" for digital music, usually enforced with digital "keys."

Because of the DRM-protected flavor of the AAC format, record labels at last gave the nod to Apple, and it's because of the selection of popular music made available by that deal that the iTunes Music Store has become so popular when other similar ventures without industry-placating safeguards have failed. Built directly into iTunes, the Music Store is an online library of more than two million downloadable tracks in thousands of albums by the most popular commercial artists and obscure cult idols alike. Leading the market by a wide margin against competitor stores that use the Microsoft WMA format, the iTunes Music Store lets you buy music through an online account and download it directly into your iTunes music Library. A single customer's purchased music, in AAC format, can be copied and played back on as many as five different computers, whether Windows PCs or Macs. This requires an Internet-based authorization process for each computer, however; without that authorization, you cannot open the files. To read more about the details of the DRM technology used in iTunes and the AAC format, turn to About Digital Rights Management Technology.

Fortunately, AAC files bring more to the table than just DRM restrictions; they also boast better audio quality and compression efficiency than MP3 files, making them smaller and clearer than MP3 files under most circumstances, with true separate stereo tracks and a more efficient codec (encoding and decoding) algorithm. This gives users their own good reasons to opt for AAC (which can be optionally encoded without DRM restrictions, such as if you're importing your own CDs) instead of MP3.

Note

WMA provides similar features and benefits to MP3, although the DRM infrastructure used in WMA files (depending on the specific implementation used by a retailer) can be more restrictive than what is found in AAC.

The downside of AAC files is that they're not as widely used as MP3 or even WMA files. Nearly all digital audio players can play MP3 files, and all the music players on the market displaying the Microsoft "PlaysForSure" badge are also designed to use WMA files, making them compatible with music stores other than iTunes. However, only the iPod can play AAC files. Considering that the iPod is the world's most popular portable digital music player by a huge margin, though, it's hard to see that as a drawback.

Note

iTunes supports several digital music formats other than MP3 and AAC, as described in fuller detail in About Music and Video Formats. AIFF and WAV, both uncompressed formats, preserve flawless CD-quality audio at the expense of disk space. Apple Lossless is a format that halves the size of uncompressed CD audio with no loss of quality. iTunes for Windows can even import unprotected WMA files by converting them to AAC format; see Run iTunes for the First Time and Add a Music or Video File to Your iTunes Library for more information.

With today's computer-component technology, a desktop PC or Mac can encode a full-length CD to MP3 or AAC format in as little as 1/30 of the time it takes to play it all the way through at normal speed. The resulting files usually take up between 30 and 70MB of space on your disk; this means that on a 240GB hard disk (a typical midrange size for a desktop computer in 2006), you can potentially store about 5,000 CDs worth of music, or 60,000 individual songs. Besides which, with iTunes and the iPod, you can immediately dial up exactly the song, artist, or album you want to hear, without having to get up from your seat. That's a lot better than keeping your music discs in a disorganized, overflowing rack against your wall, isn't it?