voice.listen()

The listen() method is a core function available in all Mastra voice providers that converts speech to text. It takes an audio stream as input and returns the transcribed text.

Parameters

audioStream:

NodeJS.ReadableStream | unknown

Audio to transcribe. This is usually a file stream or a microphone stream; some realtime providers accept other audio input types.

options?:

object

Provider-specific options for speech recognition

Return value

Returns one of the following:

• Promise<string>: A promise that resolves to the transcribed text
• Promise<NodeJS.ReadableStream>: A promise that resolves to a stream of transcribed text (for streaming transcription)
• Promise<void>: For real-time providers that emit 'writing' events instead of returning text directly

Provider-specific options

Each voice provider may support additional options specific to their implementation. Here are some examples:

OpenAI

options?:

Options

Configuration options.

Options

filetype?:

string

Audio file format (e.g., 'mp3', 'wav', 'm4a')

prompt?:

string

Text to guide the model's transcription

language?:

string

Language code (e.g., 'en', 'fr', 'de')

Google

options?:

Options

Configuration options.

Options

stream?:

boolean

Whether to use streaming recognition

config?:

object

Recognition configuration from Google Cloud Speech-to-Text API

Deepgram

options?:

Options

Configuration options.

Options

model?:

string

Deepgram model to use for transcription

language?:

string

Language code for transcription

Usage example

import { OpenAIVoice } from '@mastra/voice-openai'
import { getMicrophoneStream } from '@mastra/node-audio'
import { createReadStream } from 'fs'
import path from 'path'

// Initialize a voice provider
const voice = new OpenAIVoice({
  listeningModel: {
    name: 'whisper-1',
    apiKey: process.env.OPENAI_API_KEY,
  },
})

// Basic usage with a file stream
const audioFilePath = path.join(process.cwd(), 'audio.mp3')
const audioStream = createReadStream(audioFilePath)
const transcript = await voice.listen(audioStream, {
  filetype: 'mp3',
})
console.log('Transcribed text:', transcript)

// Using a microphone stream
const microphoneStream = getMicrophoneStream() // Assume this function gets audio input
const transcription = await voice.listen(microphoneStream)

// With provider-specific options
const transcriptWithOptions = await voice.listen(audioStream, {
  language: 'en',
  prompt: 'This is a conversation about artificial intelligence.',
})

Using with CompositeVoice

When using CompositeVoice, the listen() method delegates to the configured listening provider:

import { CompositeVoice } from '@mastra/core/voice'
import { OpenAIVoice } from '@mastra/voice-openai'
import { PlayAIVoice } from '@mastra/voice-playai'

const voice = new CompositeVoice({
  input: new OpenAIVoice(),
  output: new PlayAIVoice(),
})

// This will use the OpenAIVoice provider
const transcript = await voice.listen(audioStream)

Using AI SDK Model Providers

You can also use AI SDK transcription models directly with CompositeVoice:

import { CompositeVoice } from '@mastra/core/voice'
import { openai } from '@ai-sdk/openai'
import { groq } from '@ai-sdk/groq'

// Use AI SDK transcription models
const voice = new CompositeVoice({
  input: openai.transcription('whisper-1'), // AI SDK model
  output: new PlayAIVoice(), // Mastra provider
})

// Works the same way
const transcript = await voice.listen(audioStream)

// Provider-specific options can be passed through
const transcriptWithOptions = await voice.listen(audioStream, {
  providerOptions: {
    openai: {
      language: 'en',
      prompt: 'This is about AI',
    },
  },
})

See the CompositeVoice reference for more details on AI SDK integration.

Realtime voice providers

When using realtime voice providers like OpenAIRealtimeVoice, the listen() method behaves differently:

• Instead of returning transcribed text, it emits 'writing' events with the transcribed text
• You need to register an event listener to receive the transcription

import { OpenAIRealtimeVoice } from '@mastra/voice-openai-realtime'
import { getMicrophoneStream } from '@mastra/node-audio'

const voice = new OpenAIRealtimeVoice()
await voice.connect()

// Register event listener for transcription
voice.on('writing', ({ text, role }) => {
  console.log(`${role}: ${text}`)
})

// This will emit 'writing' events instead of returning text
const microphoneStream = getMicrophoneStream()
await voice.listen(microphoneStream)

Notes

• Not all voice providers support speech-to-text functionality (e.g., PlayAI, Speechify)
• The behavior of listen() may vary slightly between providers, but all implementations follow the same basic interface
• When using a realtime voice provider, the method might not return text directly but instead emit a 'writing' event
• The audio format supported depends on the provider. Common formats include MP3, WAV, and M4A
• Some providers support streaming transcription, where text is returned as it's transcribed
• For best performance, consider closing or ending the audio stream when you're done with it

Related methods

• voice.speak(): Converts text to speech
• voice.send(): Sends audio data to the voice provider in real-time
• voice.on(): Registers an event listener for voice events