Splitting audio into narrow frequency bands removes redundancy and enables efficient perceptual quantization

Evidence

It also allows the coder to flag bands that contain no energy at all and therefore no information needs to be transmitted. These scale factors and unused band information need to be transmitted to the decoder and therefore represent additional side information to be encoded and transmitted to the decoder. The signal within the bands is also less correlated because, as the band gets narrower in frequency range, the spectrum within the band is more likely to be uniform, and thus approaches the desired white noise spectrum with zero correlation between samples. A further advantage of frequency domain processing is that it converts the audio signal into a form that makes it easy for psychoacoustic quantization to be efficiently applied. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2605

Categorization

• DEFINE: Concretely defines the mechanism of sub-band coding: scale factors, flagged silent bands, and whitening toward zero inter-sample correlation.