Spring AI, Whisper, and Text-to-Speech

This is a sample application showing how to capture audio from a webpage, submit it to a Spring MVC controller, and submit it to OpenAI's Whisper API to get a transcription. That transcription is then sent to OpenAI's gpt-3.5-turbo model to get a response. Finally, the response is then sent to the text-to-speech API to get an audio response that is returned to the client.

Note that at the moment, the prompt sent to the gpt-3.5-turbo model includes text asking for the response to be kept brief. At this time, no conversational memory or RAG is applied to the prompt for context (but that could change in the future).

Building and running the application

Before running the application, you'll need to obtain an OpenAI API key and set it to the OPENAI_API_KEY environment variable. E.g.,

% export OPENAI_API_KEY=sk-...

This is a Spring Boot application built with Maven. Therefore, you can run the application just like any other Spring Boot application using the Spring Boot Maven plugin:

% ./mvnw spring-boot:run

Or you can build it to an executable JAR file and then run it:

% ./mvnw package
% java -jar target/speechai-0.0.1-SNAPSHOT.jar

Using the application

Once the application is running, open http://localhost:8080/ask in your web browser. Press and hold the "Listen" buttons while talking.

After releasing the "Listen (Whisper API)" button, the audio captured by the browser will be sent to the server and from there to OpenAI's Whisper API for transcription. From there the transcritpion will be sent to OpenAI's gpt-3.5-turbo model to get a response. Finally, the response will be sent to the text-to-speech API to get an audio response that is returned to the client.

A few notes...

• At this time, Spring AI does not (yet) support integration with OpenAI's Whisper or TTS APIs. Therefore, this application is invoking those APIs directly using Spring's RestClient in the SpeechClient class.
• I've tested this on Chrome, Firefox, and Safari web browsers. It works on all three, but Safari doesn't seem to capture everything said when the "Listen" button is held (for some reason). Most of my testing has been with Chrome and it works incredibly well. I welcome any insight into why it doesn't work as well with Safari.