Audio signal processing apparatus, audio coding apparatus, and audio decoding apparatus

摘要

An audio signal processing apparatus which can perform, with low operation amount, audio signal processing that is either time stretch and/or compression processing or frequency modulation processing. The audio signal processing apparatus is intended to transform an input audio signal sequence using a predetermined adjustment factor. The audio signal processing apparatus includes a filter bank which transforms the input audio signal sequence into Quadrature Mirror Filter QMF coefficients and an adjusting unit which adjusts the QMF coefficients based on a predetermined adjustment factor, wherein said adjusting unit further includes a bandwidth restricting unit configured to extract, from the QMF coefficients, new QMF coefficients corresponding to a predetermined bandwidth, either before or after the adjusment of the QMF coefficients.