About mp3

MP3, short for MPEG-1/MPEG-2 Layer 3, is a format for storing digital audio. It uses an advanced type of audio compression, which reduces the file size with little reduction in audio quality. mp3 is used in software applications, digital audio players, home stereo devices and music distribution over the Internet, but is also used for other purposes such as real-time digital audio transmissions over ISDN.

An mp3 file (or simply an mp3) is a file that contains mp3-compressed audio data. It is played using an mp3 player. You can recognize mp3 files by their file-extension (the end of the filename), which is .mp3.

Over one billion music tracks are currently downloaded every month on the Internet using mp3, practically every PC contains licensed mp3 software, virtually every song has been mp3-encoded and some 150 million mp3 players are expected to reach the global market by year's end, making it the Web's most popular audio compression format by far.

The history of mp3

In the 1980s, the International Organization for Standardization (ISO) and the International Electrotechnical Commision (IEC) set up the Moving Pictures Expert Group (MPEG) to develop standards for the coded representation of moving pictures. In December 1988, at a meeting held at Deutsche Thomson Brandt's Hanover offices, the MPEG decided to introduce audio coding within its terms of reference.

The research on compression of music files had been carried out by a team of scientists under Prof. Karlheinz Brandenburg, working at the Fraunhofer Institute for Integrated Circuits (Fraunhofer IIS) in Bavaria. Brandenburg first built a refrigerator-size machine that could reduce a sound file to 8 percent of its original size, then concentrated on replicating its effects through an algorithm.

The result was the "MPEG-1 Layer 3" algorithm described in the ISO/IEC IS 11172-3 and ISO/IEC IS 13818-3 standard documents. Its name was first shortened to "MPEG Layer 3" and later further shortened for convenience to the file suffix "mp3".

Format inventor Brandenburg worked for nearly 20 years to develop and bring to market what the world has come to know as mp3. He did not merely create a software program - he developed the very basis for perceptual audio coding technology.

To create mp3, Brandenburg analyzed how the human ear and brain perceive sound. The coding technique effectively fools the ear by eliminating the less essential parts of a music file. For example, if two notes are very similar, or if a high and low tone occur at exactly the same time, the brain perceives only one of them; so the mp3 algorithm selects the more important signal and discards the other.

The resulting mp3 file is reduced to less than a tenth of the original size of the audio file. For example, a three-minute track will normally take up about 30MB of hard-disk space. The equivalent mp3 file will use only about 3MB of space with little audible loss in quality.

Through the early 90s, mp3 was mainly used in professional applications. In these pre-Web days, Thomson was the only major industrial player to share Brandenburg's vision, and its engineers worked alongside the Fraunhofer team to develop and improve mp3 encoding and decoding applications. Their combined research and development resulted in twenty patents covering the mp3 standard, with Thomson issuing the licenses under these patents from 1993 onward.






 

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