New refinement schemes for voice conversion

New refinement schemes for voice conversion are proposed in this paper. We take mel-frequency cepstral coefficients (MFCC) as the basic feature and adopt cepstral mean subtraction to compensate the channel effects. We propose S/U/V (silence/unvoiced/voiced) decision rule such that two sets of codebooks are used to capture the difference between unvoiced and voiced segments of the source speaker. Moreover, we apply three schemes to refine the synthesized voice, including pitch refinement with PSOLA, energy equalization, and frame concatenation based on synchronized pitch marks. The satisfactory performance of the voice conversion system can be demonstrated through ABX listening test and MOS grade.