Agent Voice Response - Google Cloud Text-to-Speech Integration

This project demonstrates the integration of Agent Voice Response with Google Cloud Text-to-Speech (TTS). The application sets up an Express.js server that accepts a text string from a client via HTTP POST requests, converts the text into speech using Google Cloud TTS, and streams the audio back to the client in real-time.

Prerequisites

To run this project, you will need:

1. Node.js and npm installed.
2. A Google Cloud account with the Text-to-Speech API enabled.
3. A Service Account Key from Google Cloud with the necessary permissions for Text-to-Speech API.

Setup

1. Clone the Repository

git clone https://github.com/agentvoiceresponse/avr-tts-google-cloud-tts
cd avr-tts-google-cloud-tts

2. Install Dependencies

npm install

3. Configure Google Cloud Credentials

Create a keyfile.json by downloading your service account key from Google Cloud. Set the environment variable to use this key in your Node.js application:

export GOOGLE_APPLICATION_CREDENTIALS="/path/to/keyfile.json"

Alternatively, use a .env file to load environment variables:

GOOGLE_APPLICATION_CREDENTIALS=/path/to/keyfile.json
TEXT_TO_SPEECH_LANGUAGE=en-AU
TEXT_TO_SPEECH_GENDER=FEMALE
TEXT_TO_SPEECH_NAME=en-AU-Neural2-C
TEXT_TO_SPEECH_SPEAKING_RATE=1
PORT=6003

4. Configure Environment Variables

Make sure you have the following environment variables set in a .env file for flexible configuration:

TEXT_TO_SPEECH_LANGUAGE=en-AU
TEXT_TO_SPEECH_GENDER=FEMALE
TEXT_TO_SPEECH_NAME=en-AU-Neural2-C
TEXT_TO_SPEECH_SPEAKING_RATE=1
PORT=6003

You can modify the language code, gender, and voice model based on your requirements.

How It Works

The application accepts a text input from the client via an HTTP POST request to the /text-to-speech-stream route, converts the text into speech using Google Cloud Text-to-Speech, and streams the resulting audio back in LINEAR16 encoding, suitable for integration with Asterisk Audio Socket.

Key Components

• Express.js Server: Handles incoming HTTP POST requests with the text body and streams the audio back to the client.
• Google Cloud Text-to-Speech Client: Converts text into speech using the TTS API.
• Audio Streaming: The audio data is streamed back to the client in chunks for real-time playback.

Example Code Overview

• Google Cloud TTS Request Configuration: Set up voice settings like language, gender, and audio encoding.
• Audio Streaming: The application splits the audio content into chunks and streams it back to the client using the res.write() method.

Running the Application

To start the application:

node index.js

The server will start and listen on the port defined in the environment variable or default to 6003.

Sending a Text Request

You can use curl to send a POST request to the server with a JSON body containing a text field:

curl -X POST http://localhost:6003/text-to-speech-stream \
     -H "Content-Type: application/json" \
     -d '{"text": "Hello, welcome to Agent Voice Response!"}' --output response.wav

The audio response will be saved in response.wav in the specified format.

Support & Community

• GitHub: https://github.com/agentvoiceresponse - Report issues, contribute code.
• Discord: https://discord.gg/DFTU69Hg74 - Join the community discussion.
• Docker Hub: https://hub.docker.com/u/agentvoiceresponse - Find Docker images.
• Wiki: https://wiki.agentvoiceresponse.com/en/home - Project documentation and guides.

Support AVR

AVR is free and open-source. If you find it valuable, consider supporting its development:

License

MIT License - see the LICENSE file for details.