Directly modeling speech waveforms by neural networks for statistical parametric speech synthesis

This paper proposes a novel approach for directly-modeling speech at the waveform level using a neural network. This approach uses the neural network-based statistical parametric speech synthesis framework with a specially designed output layer. As acoustic feature extraction is integrated to acoustic model training, it can overcome the limitations of conventional approaches, such as two-step (feature extraction and acoustic modeling) optimization, use of spectra rather than waveforms as targets, use of overlapping and shifting frames as unit, and fixed decision tree structure. Experimental results show that the proposed approach can directly maximize the likelihood defined at the waveform domain.