This software is a patch to HMM based statistical parametric speech synthesis toolkit (HTS 2.2).
Vocal tract length normalization (VTLN) is a rapid adaptation technique and transforms spectral characteristics of the speech to match the gender of the target speaker. This code can perform estimation of Bilinear transform based warping factors for Mel-generalized cepstral (MGCEP) features. This code includes the possibility to perform VTLN adaptation as a global warping of the spectrum using base classes and also as multiple warping parameters for different phoneme classes using regression trees (similar to CMLLR adaptation). Please check the README file for more details of using the code. Please download the patch