Time-scale Modification using the Phase Vocoder

摘要: The phase vocoder has been used as a time-scale-modification tool for several decades. Applying large positive modification factors to different kinds of sounds (time-stretching), the result will always sound “phasy” or “reverberant”. quality can be improved by “locking” phases. Phase-locking preserves relations around local maximum in magnitude spectrum. For factors, locking entire spectrum “rigid”. In this work, deterministic and stochastic components are separated frequency domain, only phases sinusoids locked, while remaining set random numbers. part is detected within “reduced variance” using heuristic conditions. reduced variance calculated weighting actual spectrum, frame about 11 ms advance before way, approximation peak-detection yielding better results noise-like signals. resynthesis, magnitudes combined with smoothed magnitudes, locked