Recently, denoising diffusion probabilistic models and generative score matching have shown high potential in modelling complex data distributions while stochastic calculus has provided a unified point of view on these techniques allowing for flexible inference schemes. In this paper we introduce Grad-TTS, a novel text-to-speech model with score-based decoder producing mel-spectrograms by gradually transforming noise predicted by encoder and aligned with text input by means of Monotonic Alignment Search. The framework of stochastic differential equations helps us to generalize conventional diffusion probabilistic models to the case of reconstructing data from noise with different parameters and allows to make this reconstruction flexible by explicitly controlling trade-off between sound quality and inference speed. Subjective human evaluation shows that Grad-TTS is competitive with state-of-the-art text-to-speech approaches in terms of Mean Opinion Score. We will make the code publicly available shortly.

Grad-TTS是一款使用基于得分的解码器的文本转语音模型，使用随机微积分的方法将通过噪声预测的语音信号和文本输入进行逐步变换，从而实现噪声到语音的重建，并能够在保持音质、推理速度之间进行灵活平衡。主观人评表明Grad-TTS在Mean Opinion Score方面具有与最先进的文本转语音方法相竞争的能力。

Grad-TTS: 一种文本转语音的扩散概率模型