颠覆性设计的端到端语音合成系统Tacotron 2,目前仅能处理英文.致力于对Tacotron 2进行多方位改进,设计了一种中文语音合成方案,主要包括:针对汉字不表音、变调和多音字等问题,添加预处理模块,将中文转化为注音字符;针对现有中文训练语料不足的情况,使用预训练解码器,在较少语料上获得了较好音质;针对中文语音合成急促停顿问题,采用对交叉熵损失进行加权,并用多层感知机代替变线性变换对停止符进行预测的策略,获得了有效改善;另外通过添加多头注意力机制进一步提高了中文语音合成音质.梅尔频谱、梅尔倒谱距离等的实验对比结果表明了方案的有效性:可以令Tacotron 2较好地适应中文语音合成的要求.
The disruptively design for an end-to-end speech synthesis system Tacotron 2, is currently only available in English. This paper is devoted to implementing several improvements to Tacotron 2 and presents a Chinese speech synthesis scheme, including:a pre-processing module to convert Chinese characters into phonetic characters to address the challenge of Chinese character not corresponding to pronunciation, having multiple tones, and having polyphonic words; a pre-training decoder to achieve better sound quality with less corpus given the lack of existing Chinese training corpus; a strategy of weighting the cross-entropy loss and using the multi-layer perceptron, instead of the linear transformation, to predict stop tokens and to solve the Chinese speech synthesis sudden pause problem; and a multi-head attention mechanism to further improve Chinese speech quality. The experimental comparison of the Mel spectrum and the Mel cepstrum distance (MCD) shows that our work is effective and can make Tacotron 2 adapted to the requirements of Chinese speech synthesis.
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