Abstract
The purpose of this study was to show that an enhanced prosody transplantation system for Mandarin Chinese not only achieve pitch conversion, duration conversion, and energy conversion, but also upgrade naturalness and eliminate distortions.UPDUDP (unbroken pitch determination using dynamic programming) is first applied to each utterance for pitch tracking which extracts an unbroken pitch contour from a given utterance based on time-domain acoustic feature of AMDF (average magnitude difference function) and DP (dynamic programming). Utterances are then segmented into phonemes using Viterbi decoding for forced alignment.A DP-based pitch marking method is utilized for detecting pitch marks in a reliable manner. First we select either peaks (local maxima) or valleys (local minima) for pitch mark candidates according to its similarity to an estimated pitch curve. Based on the candidates, we define state and transition probabilities and then employ DP to find the most likely pitch marks.The voiced characteristics of each utterance are then extracted to perform prosody transplantation. The PSOLA (pitch synchronous overlap and add) technique in time domain is used to adjust the fundamental frequency to achieve pitch conversion. WSOLA (waveform similarity overlap and add) is employed to adjust duration. Frame size is set to be the interval between one pitch mark and the next pitch mark of source wave and target wave. The volume for each frame is thus computed and linear mapping is executed. Energy conversion is then achieved by adjusting the source energy to the target energy.