Audio compression exploits masking to discard inaudible signal parts

Evidence

In order to make the reduction of information flow inaudible, it is best to use the characteristics of the human ear as an information receiver, and reduce the information flow for those events that are already inaudible. The effect of masking is a typical example. It can be introduced into the processing system in such a way that those parts masked by loud sounds are not transmitted to the receiver. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2020

Masking is exploited practically in digital systems that store and transmit digital audio in order to reduce the amount of information that has to be handled, and therefore reduces the transmission resource, or bandwidth, and memory, hard disk or other storage medium required. Such systems are generally referred to as “perceptual coders” because they exploit knowledge of human perception. For example, perceptual coding is the operating basis of MP3 systems. It is also used to transmit music over the Internet, in MP3 players that store many hours of such music in a pocket-sized device, in multi-channel sound in digital audio broadcasting and in satellite television systems, MiniDisk recorders (Maes, 1996), and the now obsolete digital compact cassette (DCC). — David Howard, Jamie Angus, coustics and Psychoacoustics, 1656

Categorization

• ADDENDUM: This is the engineering rationale behind perceptual audio codecs like MP3/AAC, complementing a general piece on how the ear’s limitations enable efficient signal transmission.
• DEFINE: Defines perceptual coders as systems that exploit knowledge of human perception to discard masked audio.
• corroborated: 3 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2020; David Howard, Jamie Angus, coustics and Psychoacoustics, 1656
• XREF: connects to: Audio compression maximizes information by encoding only unpredictable signal parts; Perceptual coders exploit masking to cut audio storage and bandwidth — David Howard, Jamie Angus, coustics and Psychoacoustics, 1656; Masked audio components below the masking threshold need no bits transmitted (+11 more)

Broader Connections

• Perceptual coders exploit masking to cut audio storage and bandwidth #corroborates (1.00) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1656
• Masked audio components below the masking threshold need no bits transmitted #expands (1.00)
• Lossy coding exploits psychoacoustic models to make removed information inaudible #corroborates (0.95) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2581
• Audio compression maximizes information by encoding only unpredictable signal parts #expands (0.90)