`stream()`

The stream() method is used to interact with the TTS model to produce an audio response stream. This method accepts text and voice as parameters.

Parameters

text:

string

The messages to be processed by TTS.

voice:

string

Voice ID to be used with generation.

Returns

audioResult?:

Readable

The generated audio stream

Examples

Basic Audio Stream (ElevenLabs)

import { ElevenLabsTTS } from '@mastra/tts'
 
 const tts = new ElevenLabsTTS({
    model: {
      name: 'eleven_multilingual_v2',
      apiKey: process.env.ELEVENLABS_API_KEY!,
    },
  });
 
const voices = await tts.voices();
const voiceId = voices?.[0]?.voice_id!;
 
const { audioResult } = await tts.stream({ text: "What is AI?", voice: voiceId });
 
// Create a write stream to simulate real-time playback
const outputPath = path.join(process.cwd(), '/test-outputs/streaming-output.mp3');
const writeStream = createWriteStream(outputPath);
 
let firstChunkTime: number | null = null;
let lastChunkTime: number | null = null;
let totalChunks = 0;
 
// Process chunks as they arrive
for await (const chunk of audioResult) {
    if (!firstChunkTime) {
    firstChunkTime = Date.now();
    }
    lastChunkTime = Date.now();
    totalChunks++;
 
    // Write chunk immediately as it arrives
    writeStream.write(chunk);
 
    // Log timing of chunk arrival
    console.log(`Received chunk ${totalChunks} at ${lastChunkTime - firstChunkTime!}ms`);
}
 
writeStream.end()

Basic Audio Stream (OpenAI)

import { OpenAITTS } from '@mastra/tts'
 
 const tts = new OpenAITTS({
    model: {
      name: 'tts-1',
      apiKey: process.env.OPENAI_API_KEY!,
    },
  });
 
const voices = await tts.voices();
const voiceId = voices?.[0]?.voice_id!;
 
const { audioResult } = await tts.stream({ text: "What is AI?", voice: voiceId });
 
// Create a write stream to simulate real-time playback
const outputPath = path.join(process.cwd(), '/test-outputs/streaming-output.mp3');
const writeStream = createWriteStream(outputPath);
 
let firstChunkTime: number | null = null;
let lastChunkTime: number | null = null;
let totalChunks = 0;
 
// Process chunks as they arrive
for await (const chunk of audioResult) {
    if (!firstChunkTime) {
    firstChunkTime = Date.now();
    }
    lastChunkTime = Date.now();
    totalChunks++;
 
    // Write chunk immediately as it arrives
    writeStream.write(chunk);
 
    // Log timing of chunk arrival
    console.log(`Received chunk ${totalChunks} at ${lastChunkTime - firstChunkTime!}ms`);
}
 
writeStream.end()

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