About Digital Music Technology

"But wait," you might be saying. "I thought compact discs were all about digital audio, which is what made them better than cassette tapes 25 years ago. How is the digital audio from a CD different from what is considered digital music in the iTunes world?" That's a fair question. In fact, it's got a good illustration built right into it. Think of digital music in the iTunes age as being to CDs what CDs were to tapes. Tapes are linear; you have to play straight through the tape from beginning to end, and you can only skip around blindly using the fast-forward and rewind buttons. On the other hand, CDs are a digital medium, with true random access to the songs on the disc, which means that the player can access any given song on the disc on command. With a CD, you can do such things as program the tracks to play in a certain order, randomly select songs from various discs in a changer, and so on. These features just weren't possible on an analog medium like the cassette tape, where the audio content consists of nothing more than a long, unbroken stream of magnetic material that is interpreted during playback as different kinds of sound waveforms. The same huge leap in flexibility that we enjoyed in moving from tapes or vinyl records to CDs is now present as we move from CDs to pure digital music on our computers: Instead of the music data being stored on a physical disc that has to be moved around and manually loaded into a player, it's stored in the form of easily portable data files that can be played back in any order, modified, organized into playlists, navigated by artist or album or genre, or copied from device to device by simply giving a command in software.

It wasn't until the mid-1990s, when a couple of technical breakthroughs occurred, that this quantum leap in portability and control became possible. First, a compression algorithm (MP3) was developed that shrunk the digital audio data from the uncompressed format in which it's stored on CDs (about 10MB per minute, which is far too large to be practical) to one in which large music collections could be conveniently stored on typical computer hard drives or transferred easily over the Internet. Additionally, computers' processor speeds rose to the point where desktop PCs could quickly and easily convert CD music data to the compressed format and decompress the data for immediate, convenient playback so that computer users could enjoy their music without getting up from their desks.

The MP3 Revolution

Developed in the early 1990s, MPEG-1 level 3 (MP3) became the first widely accepted encoding format that enabled the meteoric rise in popularity of digital music, even though it was underground and largely illicit at first. College students and young computer geeks with fast Internet connections used free or inexpensive encoding software (licensed from bodies such as the Fraunhofer Institute, which holds the rights to the MP3 encoding algorithm) to convert their purchased CDs into MP3 format. After they converted these files to the compressed digital format, the files immediately took on a life of their own, taking advantage of their relatively small size (usually 3 to 5 megabytes (MB) per song) and the explosive growth of the Internet to leap from computer to computer by way of the new breed of "peer-to-peer" software (such as Napster) that allowed MP3 collectors to seek out music on others' computers and quickly download it for free. Artists and record labels initially dismissed the threat that MP3 file sharing presented to their business model. However, soon it became apparent that the problem was not going to go away on its ownCD sales were slipping noticeably, and it would only get worse with time. A few high-profile lawsuits against MP3 collectors and broadcasters, and the legal shutdown of the original Napster service, officially placed free music file sharing into the public eyeto some, an honorable form of rebellion against corporate tyranny; to others, the very act of killing the goose that lays the golden eggs.

Key Term

MPEG-1 level 3 (MP3) The most widely used format for digital music, MP3 files sound pretty good but have no copy protection built in.

Notes

It's always been perfectly legal to copy a CD to MP3 format for your own use; it's just the unrestricted transmission of these unprotected music files to other, unrelated computer users that's illegal and a violation of copyright law.

Some countries have laws prohibiting copy-protection and DRM on media files; in some countries, the legal status of the digital music medium is still being contested. This book's discussion of legal issues is primarily based on the situation in the United States. If you live elsewhere, be aware of the laws of your own country with regard to these technologies.

There was no denying the advantages of digital music, after all. As long as you're using MP3s responsibly, if you've used them once, it's hard to go back. The convenience of playing a favorite song with a simple double-clickinstead of digging out a CD and skipping to the appropriate numbered track as directed by the liner notesis a difference of night and day. Similarly, CDs simply cannot compare to the organizational benefits of setting the info tags (or ID3 tags) on files so that you can immediately navigate to them by publication year, genre, track number, beats per minute, or even embedded album art images. Quickly and easily creating a mix CD from a list of MP3 files is a giant leap above the laborious, hours-long process of manually dubbing songs to a mix cassette tape as in the old days. Today, it involves little more than arranging the appropriate songs in the right order, inserting a writable CD, and clicking a "burn" button.

Key Term

Info tags Data fields built into a digital audio file that contain the song's title, artist, album, track number, album art, and other information. Often called ID3 tags in MP3 files; also referred to generically as metadata.

The small size and platform independence of MP3 files led to the inevitable creation of portable music players such as the iPod. Because MP3 files inside your computer didn't actually take up physical space (unlike bulky racks of CDs), the only limitation on how small a portable device could be made was in how large the screen and controls had to be to allow for easy navigation of your music. As an illustration, the iPod can't be made much smaller than the iPod nano varietyeven if hard drive technology allowed the same storage capacity in a smaller packagebecause the user still has to work the wheel and buttons with her thumb, and the screen must be large enough to be readable while still retaining the six or seven lines of textual information that make the iPod's scrolling navigation so usable. These limitations are a far cry from the ones that dictate the shape of a portable CD player such as a Sony Discman: no matter how small the technology of such a device gets, the overall unit can never get smaller than the five-inch bulk of a CD. The user also has to hold the disc player horizontally and keep it from being jolted, which is all but an irrelevancy to digital music playersespecially solid-state ones like the iPod shuffle and iPod nano.