MP3 is an audio file format commonly used for audio file storage, distribution, streaming, and playback on personal digital audio players known as MP3 players.
The MP3 file format is a shortened version of the full name: MPEG-1 or 2 Audio Layer III. MP3 is a lossy file format that is a popular choice for audio files that will be streamed online, copied to a media player (MP3 player), or shared over the Internet.
The MP3 format was originally released publicly in 1993, with updates in 1995 and 1998. During the second half of the 1990s, MP3's became a popular format for storage of audio files on a computer hard drive and distribution of audio files over the Internet. In particular, the MP3 rapidly gained popularity, or notoriety depending on who you ask, as a format that was ideally suited to sharing over the Internet, either at download sites or over peer-to-peer file sharing networks.
Portable digital audio players called MP3 players came on the market in 1998 despite opposition by the Recording Industry Association of America (RIAA) over concerns that availability of these devices would encourage music piracy and negatively affect record sales – an all-too-accurate prediction. Peer-to-peer sharing networks such as Napster began to pop up beginning in 1999 and enabled widespread sharing of copyrighted audio content which could be easily played from any computer or copied to a portable MP3 Player.
Mainstream peer-to-peer networks that enabled illegal music sharing have been largely forced out of operation through legal action and have been replaced by authorized services which sell downloadable audio files or offer streaming audio content.
What does it mean that MP3 is a lossy format?
The MP3 format is designed to require significantly less space than a CD file. An MP3 file compressed at a sampling rate of 128 kilobits per second (kbps) will require less than 10% the disc space of the same uncompressed file on a CD. This is because the sampling rate of a CD recording is approximately 1.4 Mbps (1,400 kbps).
MP3s accomplish this massive reduction in disc space by reducing the reproduction of sounds that are outside the hearing range of most people. While 128 kbps is the most common sampling rate for an MP3, other rates can also be used. Higher rates will produce a higher-quality recording, but also require more disc space, while lower quality rates will require less disk space but sacrifice sound quality in the process.
What was the original intended purpose of the MP3 format?
When the MP3 format was developed in the early 1990s the average computer hard drive was only 500 MB to 1 GB. This means that copying CD-quality audio files to a computer hard drive was a virtual non-starter due to a lack of available storage space. The answer was to find a way to compress the audio files while preserving the quality of the audio to a level that most people would find undiscernable when compared to the original recording. The MP3 format accomplished this. It allowed compression of audio files to less than 10% their original size while preserving the quality of the recording.
The MP3's adoption as a file format ideally suited to music piracy was an unintended consequence of the technology.