Crystal Text-to-Speech (TTS) Engine
The Crystal Text-to-Speech (TTS) Engine is a highly advanced system implemented in C++ that enables the conversion of text into speech across various languages. This sophisticated engine is built on a unified framework designed to support multilingual text-to-speech synthesis, ensuring standardization and compatibility across different languages and dialects. Below, we delve into the key aspects of this remarkable project.
Architecture
At the core of the Crystal TTS Engine is its architecture, which is built to seamlessly integrate different TTS modules for a range of languages. The architecture adheres to the Speech Synthesis Markup Language (SSML) specification, which acts as a standardized interface between the modules. This approach not only enhances interoperability between systems but also allows for scalability and flexibility in TTS solutions.
Reference
For those interested in the theoretical foundation and detailed design of the Crystal framework, the critical paper titled "A Unified Framework for Multilingual Text-to-Speech Synthesis with SSML Specification as Interface" by Zhiyong Wu, Guangqi Cao, Helen Meng, and Lianhong Cai is recommended. This document was published in Tsinghua Science and Technology and can provide valuable insight into the motivations and methodologies behind Crystal's development.
Native Support of SSML
One of the Crystal TTS Engine's standout features is its native support for SSML, which serves as the lingua franca between its modules. By using SSML, the engine simplifies the process of implementing new algorithms. Developers can focus on creating these algorithms by leveraging internal data structures rather than concerning themselves with the intricate parsing of SSML documents. This is made possible through the framework's cst::xml::CSSMLTraversal component, which efficiently converts SSML documents into a usable format.
Support of Dynamic Module Loading & Cross-platform
Crystal's framework is designed to accommodate the dynamic loading of modules, allowing it to operate across various platforms. Developers can create specialized algorithms for each TTS module, compile them into dynamic libraries, and then load these as needed using an XML configuration file. This approach provides incredible adaptability, enabling users to switch between different TTS engines and algorithms seamlessly.
For example, the configuration "cmn.xml" could activate a Concatenative Putonghua TTS engine, while "zh.xml" might initialize a HMM-based Chinese TTS engine, showcasing the framework's versatility in handling diverse linguistic needs.
Support of Multilingual TTS Engine
The Crystal TTS framework supports the development and implementation of TTS engines across multiple languages by allowing the customization of its base modules. By doing so, it offers a flexible platform where various languages can be supported via tailored adaptations of its core components. This multilingual capability is a testament to the Crystal TTS Engine's adaptability and expansive reach.
About the Project
This innovative TTS Engine is a product of the joint efforts of the Tsinghua-CUHK Joint Research Center for Media Sciences, Technologies and Systems. The collaborative environment has contributed to the engine's comprehensive capabilities and sophisticated design. The project's custodians hold the rights to create, modify, compile, and distribute its source code, ensuring continuous development and innovation.
For more information, one can visit the center's website at http://mjrc.sz.tsinghua.edu.cn.