Suppression of Phasiness for Time-Scale Modifications of Speech Signals Based on a Shape Invariance Property

Colloque avec actes et comité de lecture. internationale.International audienceTime-scale modifications of speech signals, based on frequency-domain techniques, are hampered by two important artifacts which are ''phasiness'' and ''transient smearing''. They correspond to the destruction of the shape of the original signal, i.e. the de-synchronization between the phases of frequency components. This paper describes an algorithm that preserves the shape invariance of speech signals in the context of a phase vocoder. Phases are corrected at the onset of each voiced region. Modified signals, even for large expansion factors, are of high quality and free from transient smearing or phasiness. A demonstration is proposed in the web page: http://www.loria.fr/~jdm/PhaseVocoder/index.html where some audio files can be down-loaded