MP3 for Dummies

Illustration By Nathan Jensen

If you are sick and tired of hearing about MP3s because you don't know what they are, or you download them like crazy and still have no idea what they are apart from songs, then this little primer's for you.

Currently, MP3 is the most widely used format for storing digital music on computer hard drives and trading it over the Internet. Why? One reason is compression, one of those rare computer terms that accurately describes itself. Compression takes a file -- a text document, picture, song, and -- you guessed it -- makes it smaller.

If you pop a normal, commercially produced music CD into your computer and look at one of the four-minute songs, you'll find it's about 40 megabytes (MBs) in size. What does that mean? Not much, except that it's relatively large.

How large? Considering one floppy disc holds 1.4 MBs of information, to store that single four-minute song would take about 29 floppies. At that size, it's a bit inconvenient to try and share, or even store on your computer's hard drive, but what if you could make that file much, much smaller? That's what MP3 does.

MP3 is actually short for MPEG-1 audio layer 3. Without getting too technical, MPEG refers both to the organization, the Moving Pictures Experts Group, which sets certain standards for the compression of digital video and audio, and to the compression itself.

Huh? Just know that MP3 is a particular type of compression, and that it's a pretty good one. Audio layer 3, the "3" of "MP3," allows for audio compression at a 12:1 ratio. That means that once compressed using the MP3 algorithm, our four-minute, 40-MB song is now only about 3.5 MBs.

But that's only part of the reason it's so popular. There are scads of compression algorithms floating around that crunch down an audio file to a smaller size, but many of them (or many early ones anyway) result in a file of such poor quality that it's not worth listening to.

One of the beauties of MP3, is that it not only results in a much smaller file, but one without a perceptible drop-off in audio quality. There's some loss, but only audiophile types would likely deem it unacceptable. For most people, there's not enough of a quality drop to preclude listening.

So now you've got a file that's small and of pretty good audio quality. Nice, if you want to back up your CD collection to a computer hard drive. Rather, it's the ability to share these things via the Internet that's fueled the proliferation of the MP3 file format. And there are two, possibly three, primary factors that have made MP3s so Net-friendly (or made the Net so MP3-friendly).

One is the increasing availability of faster Internet connections. With cable modems and DSL, people are now able to download MP3 files (that is, songs) in a matter of seconds. Even with a modem and a relatively slow dial-up Internet connection, patient surfers can still retrieve MP3s in a not-too-taxing eight minutes, give or take.

Second, MP3 isn't owned by anyone -- sort of. Various companies and researchers have MPEG patents, but you don't have to pay a license fee to Microsoft or Apple or RealNetworks to use MP3. Plus, there are dozens, maybe hundreds, of free or really cheap players floating around that understand MP3s and play them back on your computer.

Also, there are dozens of free or really cheap rippers and encoders floating around, applications that pull songs off of CDs, crunch them down, and write them to your computer's hard drive. MP3 has become a de facto standard because no company has an exclusive, proprietary claim on it and it involves minimal hassle.

In other words, everyone uses it because everyone else uses it, and it's easy to use.