Fast implementation for non-linear time-scaling of stereo signals

Emmanuel Ravelli; Mark Sandler; Juan P. Bello
DAFx-2005 - Madrid
In this paper we present an improved implementation of Duxbury’s adaptive phase-vocoder approach for audio time-stretching using non-linear time-scaling and temporal masked phase locking at transients [1]. We show that the previous algorithm has some limitations, notably its slow implementation and its incapacity to deal with stereo signals. We propose solutions to this problems including: an improved transient detection, a much faster implementation using the IFFT for re-synthesis and a method for stretching stereo signals without artifacts. Finally, we provide some graphical results and quantitative measures to illustrate our improvements.