Patent ID: 8898067

Claim:
A system configured to generate a time stretched and/or frequency transposed signal from an input audio signal, the system comprising: an analysis filterbank to provide an analysis subband signal from the input audio signal; wherein the analysis subband signal comprises a plurality of complex valued analysis samples at different times, each having a phase and a magnitude; a subband processing unit configured to determine a synthesis subband signal from the analysis subband signal using a subband transposition factor Q and a subband stretch factor S; at least one of Q or S being greater than one; wherein the subband processing unit comprises a block extractor configured to repeatedly derive a frame of L input samples from the plurality of complex valued analysis samples; the frame length L being greater than one; and apply a block hop size of p samples to the plurality of complex valued analysis samples, prior to deriving a next frame of L input samples; thereby generating a suite of frames of L input samples; a nonlinear frame processing unit configured to determine a frame of processed samples from a frame of input samples, by determining for each processed sample of the frame: the phase of the processed sample by offsetting the phase of the corresponding input sample; and the magnitude of the processed sample based on the magnitude of the corresponding input sample and the magnitude of a predetermined input sample; and an overlap and add unit configured to determine the synthesis subband signal by overlapping and adding the samples of a suite of frames of processed samples; and a synthesis filterbank configured to generate the time stretched and/or frequency transposed signal from the synthesis subband signal.