Technology

Audio coding technologies like mp3 and AAC are based on psychoacoustics, meaning they can 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 consumer’s listening experience. This imperfection is a benefit for audio coding: During the process of data reduction, audio codecs analyze the signals and focus 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.

mp3 and AAC reduce the bit rate of music without noticeable loss of quality compared to the original file. Both codecs can even achieve a higher audio quality than CDs and LPs due to their substantial range of dynamics. Therefore, the right usage of mp3 and AAC never means an impairment of sound.

The main difference between mp3 and AAC is efficiency: While a minimum bit rate of 192 kbit/s should be chosen for CD quality in mp3, the same quality can be achieved in AAC with a bit rate of only 128 kbit/s.