Speech-to-Text (STT)

Speech-to-Text (STT) in Mastra provides a standardized interface for converting audio input into text across multiple service providers. STT helps create voice-enabled applications that can respond to human speech, enabling hands-free interaction, accessibility for users with disabilities, and more natural human-computer interfaces.

Configuration

To use STT in Mastra, you need to provide a listeningModel when initializing the voice provider. This includes parameters such as:

• name: The specific STT model to use.
• apiKey: Your API key for authentication.
• Provider-specific options: Additional options that may be required or supported by the specific voice provider.

Note: All of these parameters are optional. You can use the default settings provided by the voice provider, which will depend on the specific provider you are using.

const voice = new OpenAIVoice({
  listeningModel: {
    name: "whisper-1",
    apiKey: process.env.OPENAI_API_KEY,
  },
});
 
// If using default settings the configuration can be simplified to:
const voice = new OpenAIVoice();

Available Providers

Mastra supports several Speech-to-Text providers, each with their own capabilities and strengths:

• OpenAI - High-accuracy transcription with Whisper models
• Azure - Microsoft’s speech recognition with enterprise-grade reliability
• ElevenLabs - Advanced speech recognition with support for multiple languages
• Google - Google’s speech recognition with extensive language support
• Cloudflare - Edge-optimized speech recognition for low-latency applications
• Deepgram - AI-powered speech recognition with high accuracy for various accents
• Sarvam - Specialized in Indic languages and accents

Each provider is implemented as a separate package that you can install as needed:

pnpm add @mastra/voice-openai  # Example for OpenAI

Using the Listen Method

The primary method for STT is the listen() method, which converts spoken audio into text. Here’s how to use it:

import { Agent } from "@mastra/core/agent";
import { openai } from "@ai-sdk/openai";
import { OpenAIVoice } from "@mastra/voice-openai";
import { getMicrophoneStream } from "@mastra/node-audio";
 
const voice = new OpenAIVoice();
 
const agent = new Agent({
  name: "Voice Agent",
  instructions:
    "You are a voice assistant that provides recommendations based on user input.",
  model: openai("gpt-4o"),
  voice,
});
 
const audioStream = getMicrophoneStream(); // Assume this function gets audio input
 
const transcript = await agent.voice.listen(audioStream, {
  filetype: "m4a", // Optional: specify the audio file type
});
 
console.log(`User said: ${transcript}`);
 
const { text } = await agent.generate(
  `Based on what the user said, provide them a recommendation: ${transcript}`,
);
 
console.log(`Recommendation: ${text}`);

Check out the Adding Voice to Agents documentation to learn how to use STT in an agent.