Audio coding technologies like mp3 and AAC are based on psychoacoustics, hence enabling them to reduce a music item’s data rate without audible loss in quality. This is possible because the human ear is not a perfect receiver: Every song contains audio elements imperceptible to it – no matter the listener’s listening experience. This imperfection is a benefit for audio coding: During the process of data reduction audio codecs analyze the signals, focusing on the audible segments which they sophistically save for later playback or transmission. While the data volume is being reduced, the perceived audio quality remains the same. As a consequence, the necessary storage equals about 10 percent of the original file.

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