Mp3 Music

Mp3 is a type of music file, easily recognizable from the file suffix ".mp3". It stands for MPEG-1 Audio Layer-3. Audio Level 1 and 2 also exist but, despite their efforts, are not nearly as famous. What they all have in common is that they are definitions for ways of compressing audio signals that can be sent across the Internet. Audio Layer 3 is the most advanced. Not all digital music files are actually Mp3s. In fact, another format, Windows Media Audio (WMA), is widely used. However, Mp3 has become, like Kleenex, a defining term meaning all digital music files. So, how does it work?

Let's start with some old fashioned technology, the Compact Disk (CD). CDs hold data ("bits") that are read by a laser and converted into sound to be broadcast by your CD player. When a CD player reads the CD, it transfers from the CD about 1411.2 kilobits for every second of stereo sound. The so-called "bit rate" of Mp3 files is usually around 128 kilobits for every second of stereo sound, far lower than that of the CD. This is the result of a sophisticated audio compression algorithm developed with the sponsorship of the Motion Picture Experts Group (hence MPEG) and based on a psychoacoustic model (a model of how and what the human ear hears).

So how's the quality? No different to most listeners because everything about the CD sound signal that can only be heard by Superman is reduced or, to think about it another way, stripped from the signal. This leaves only the sound we average humans are interested in: from Mozart to the Red Hot Chili Peppers. That's why Mp3 is called a "lossy" format, because it literally involves the loss of parts of the audio signal. Now, some listeners can hear a loss in fidelity when, for example, they take music off a CD and transfer it into Mp3 files on their computer--a process called "ripping." But there are variables here--what exactly is the Mp3 rate (it could be more or less than 128 kilobits per second) and how good is the encoder that's making the transfer? A bad one can have detrimental effects, even on bagpipe music.

Mp3 is just one of a multitude of audio compression standards. For example, Windows Media Player has its own format called WMA (Windows Media Audio). There's also AC-3, used in Dolby Digital and DVDs. As for the future, we already have MPEG-4 AAC, which is the format used by Apple's iTunes. Even if this format were to supersede Mp3, however, it would take a while as Mp3 is so widely used.