High quality and low complexity pitch modification of acoustic signals

A high-quality and low-complexity algorithm for pitch modification of acoustic signals is proposed. It is high quality, because time-domain waveform shape and phase synchrony of a synthesized signal closely resemble that of its original signal. Low complexity is attained by performing the algorithm entirely in time domain with fast algorithm, and without resorting to complicated frequency domain analysis and synthesis. The time domain synthesis mostly consists of fast algorithms of finding minimum absolute error (MAE) and a cross fading operation for high correlation gain and phase synchrony. The MAE-based algorithm is shown to yield smaller complexity, and better performance, than other well-known correlation cost functions. Pitch modification is performed by selecting and synthesizing apposite frames from original input signals in a way such that the original waveform shape and phase synchrony are preserved. Subjective tests showed a comparable performance to that of the best known algorithms, but at much reduced complexity