![]() ![]() The list of properties include the engine name, mode name, locale and running synthesizer. When requesting a specific Synthesizer or a list of available Synthesizers this object can be passed in with specific properties to restrict the results to Synthesizers matching the defined properties only. This simple bean holds all the required properties of the Synthesizer. It has a bad name (much too generic) but as part of the upgrade to version 2.0 they will be renaming it to EngineManager which is a much better name based on what it does.įor our example, we will only use the availableSynthesizers and createSynthesizer methods. Both of these methods need a mode description which is the next class we will use.Ĭlass: This singleton class is the main interface for access to the speech engine facilities. ![]() We will be using the open source implementation from FreeTTS for our demo app but there are other implementations such as the one from Cloudscape which provides support for the SAPI5 voices that Microsoft Windows uses. In order to remain brief the remainder of the article will focus on the speech synthesis package but if you would like to know more about speech recognition visit the CMU Sphinx project.Īll the JSAPI implementations available today are compliant with 1.0 or a subset of 1.0 but work is progressing on version 2.0 (JSR113) of the API. The Java Speech API 1.0 was first released by Sun in 1998 and defines packages for both speech recognition and speech synthesis. In most cases, end users will use a single speech engine for multiple applications so they will expect any new speech enabled applications to integrate easily. The choice of speech engine and voice is subjective and may be expensive. Some users will be comfortable with a deep male voice while others may be more comfortable with a British female voice. As you can hear from the voice demo page there is a wide variety of voices with different characteristics. The JSAPI enables developers to write applications that do not depend on the proprietary features of one platform or one speech engine.ĭecoupling the engine from the application is important. The goal of JSAPI is to enable cross-platform development of voice applications. Many vendors also provide different fee schedules for distributing applications that use a voice verses audio files and/or streams produced from the voices. Depending on how many voices you use and what you are using them for the annual costs for distribution rights can run from hundreds to thousands each year. Unfortunately the best voices (as of the time of this writing) are commercial so works produced using them can not be re-distributed without fees. I put together a collection of both commercial and non-commercial voices so you can listen to them without having to setup or install anything. Most of them are very good and a few are quite exceptional in how natural they sound. There are many voices available to developers today. This chart helps in understanding what goes on inside a speech synthesis engine but as a developer you will only need to concern yourself with the first step. There are a few different ways to implement a speech synthesis engine but in general they all complete the following steps: People learn to speak at a very young age and continue to use their speaking and listening skills over the course of their lives, so it is very easy for people to recognize even the most minor flaws in speech synthesis.Īs humans it is easy to take for granted our ability to speak but it is really a very complex process. Natural sounding speech synthesis has been the goal of many development teams for a long time, yet it remains a significant challenge. If it is added on as an afterthought or a novelty it is rarely appreciated people have high expectations when it comes to speech. In the most successful applications of speech synthesis it is often central to the product requirements. It is often used to assist the visually impaired as well as provide safety and efficiency in situations where the user needs to keep his eyes focused elsewhere. Speech synthesis has proven to be a great benefit in many ways. ![]() Speech synthesis can be used to enhance the user experience in many situations but care must be taken to ensure the user is comfortable with its use. Speech synthesis, also known as text-to-speech (TTS) conversion, is the process of converting text into human recognizable speech based on language and other vocal requirements. By Nathan Tippy, OCI Senior Software Engineer ![]()
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