Have you ever wondered how it is possible to store thousands of songs—a quantity of music that would require several hundred compact disks—on a small flash player and still have a sound quality rivaling that of CDs? The secret behind such impressive audio data compression lies in a highly successful cooperative effort between two scientific disciplines that are usually found in different departments on campus, if they are found at all: psychology of hearing, or psychoacoustics, and digital signal processing. During the past 20 years, scientists and engineers from those disciplines have worked together to create perceptual-coding algorithms, or “perceptual audio coders.” Their efforts have enabled the use of the internet for music distribution and sharing and have inspired a new segment in the consumer electronics industry. If you listen to music on a modern audio player during your daily commute, the compression algorithms are based on the principles in...
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1 June 2007
June 01 2007
The perceptual basis for audio compression
Because the human ear ignores small amounts of noise that accompany a strong signal, much of the information in audio files can be thrown away with little loss of fidelity.
Physics Today 60 (6), 80–81 (2007);