PP-TTS is a streaming speech synthesis system developed by PaddleSpeech. Based on the implementation of [SOTA Algorithms](https://github.com/PaddlePaddle/PaddleSpeech/blob/develop/docs/source/released_model.md#text-to-speech-models), a faster inference engine is used to realize streaming speech synthesis technology to meet the needs of commercial speech interaction scenarios.
PP-TTS provides a Chinese streaming speech synthesis system based on FastSpeech2 and HiFiGAN by default:
- Text Frontend： The rule-based Chinese text frontend system is adopted to optimize Chinese text such as text normalization, polyphony, and tone sandhi.
- Acoustic Model: The decoder of FastSpeech2 is improved so that it can be stream synthesized
- Vocoder: Streaming synthesis of GAN vocoder is supported
- Inference Engine： Using ONNXRuntime to optimize the inference of TTS models, so that the TTS system can also achieve RTF < 1 on low-voltage, meeting the requirements of streaming synthesis
<aname="2"></a>
## 2. Characteristic
- Open source leading Chinese TTS system
- Using ONNXRuntime to optimize the inference of TTS models
- The only open-source streaming TTS system
- Easy disassembly: Developers can easily replace different acoustic models and vocoders in different languages, use different inference engines (Paddle dynamic graph, PaddleInference, ONNXRuntime, etc.), and use different network services (HTTP, WebSocket)
