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

摘要

To provide 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 (2601) which transforms the input audio signal sequence into Quadrature Mirror Filter (QMF) coefficients using a filter for Quadrature Mirror Filter analysis (a QMF analysis filter) and an adjusting unit (2602) which adjusts the QMF coefficients based on a predetermined adjustment factor.

主权项

1. An audio signal processing apparatus which transforms an input audio signal sequence according to at least one of (i) a predetermined time stretch or compression rate and (ii) a predetermined frequency modulation rate, said audio signal processing apparatus comprising:
a filter bank which transforms the input audio signal sequence into Quadrature Mirror Filter coefficients using a Quadrature Mirror Filter analysis filter for Quadrature Mirror Filter analysis; and an adjusting unit configured to (i) calculate phase information and amplitude information of the Quadrature Mirror Filter coefficients for each of a plurality of time slots of the Quadrature Mirror Filter coefficients and for each of a plurality of sub-bands of the Quadrature Mirror Filter coefficients, and (ii) adjust the phase information and the amplitude information using, for each of the time slots and for each of the sub-bands, an adjustment factor indicating the at least one of the time stretch or compression rate and the frequency modulation rate such that the input audio signal sequence being (a) time stretched at the time stretch or compressed at the compression rate or (b) frequency modulated at the frequency modulation rate can be obtained from the Quadrature Mirror Filter coefficients.