A codebook compensative voice morphing algorithm based on maximum likelihood estimation

This paper presents an improved voice morphing algorithm based on Gaussian Mixture Model (GMM) which overcomes the traditional one in the terms of overly smoothed problems of the converted spectral and discontinuities between frames.Firstly,a maximum likelihood estimation for the model is introduced for the alleviation of the inversion of high dimension matrixes caused by traditional conversion function.Then,in order to resolve the two problems associated with the baseline,a codebook compensation technique and a time domain medial filter are applied.The results of listening evaluations show that the quality of the speech converted by the proposed method is significantly better than that by the traditional GMM method,and the Mean Opinion Score (MOS) of the converted speech is improved from 2.5 to 3.1 and ABX score from 38% to 75%.