WebSocket Speed Control

async def tts_websocket_speed_async(client: AsyncCartesia) -> None:
    """Demonstrates changing speed mid-stream using generation_config."""
    output_format = {"container": "raw", "encoding": "pcm_f32le", "sample_rate": 44100}

    async with client.tts.websocket_connect() as connection:
        ctx = connection.context(
            model_id="sonic-3",
            voice={"mode": "id", "id": "6ccbfb76-1fc6-48f7-b71d-91ac6298247b"},
            output_format=output_format
        )

        print("Sending normal speed text...")
        await ctx.push("I am speaking at a normal pace. ")

        print("Sending fast speed text...")
        await ctx.push("But now I am speaking much faster!", generation_config={"speed": 1.5})

        await ctx.no_more_inputs()

        import datetime
        filename = f"tts_speed_async_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.pcm"

        with open(filename, "wb") as f:
            async for response in ctx.receive():
                if response.type == "chunk" and response.audio:
                    f.write(response.audio)

        print(f"Saved audio to {filename}")
        print(f"Play with: ffplay -f f32le -ar 44100 {filename}")

async function ttsWebsocketSpeed(client: Cartesia): Promise<void> {
  /** Demonstrates changing speed mid-stream using generation_config. */
  const ws = await client.tts.websocket();
  ws.on('error', (err) => console.error('WS error:', err.message));

  const ctx = ws.context({
    model_id: 'sonic-3',
    voice: { mode: 'id', id: '6ccbfb76-1fc6-48f7-b71d-91ac6298247b' },
    output_format: { container: 'raw', encoding: 'pcm_f32le', sample_rate: 44100 },
  });

  console.log('Sending normal speed text...');
  await ctx.push({ transcript: 'I am speaking at a normal pace. ' });

  console.log('Sending fast speed text...');
  await ctx.send({
    model_id: 'sonic-3',
    voice: { mode: 'id', id: '6ccbfb76-1fc6-48f7-b71d-91ac6298247b' },
    output_format: { container: 'raw', encoding: 'pcm_f32le', sample_rate: 44100 },
    transcript: 'But now I am speaking much faster!',
    continue: true,
    generation_config: { speed: 1.5 },
  });

  await ctx.no_more_inputs();

  const filename = `tts_speed_${timestamp()}.pcm`;
  const file = fs.createWriteStream(filename);

  for await (const event of ctx.receive()) {
    if (event.type === 'chunk') {
      if (event.audio) file.write(event.audio);
    }
  }

  file.end();
  ws.close();
  console.log(`Saved audio to ${filename}`);
  console.log(`Play with: ffplay -f f32le -ar 44100 ${filename}`);
}

cd cartesia-python
CARTESIA_API_KEY=YOUR_KEY python3 examples/async_examples.py tts_websocket_speed_async

cd cartesia-js
CARTESIA_API_KEY=YOUR_KEY npx ts-node examples/node_examples.ts ttsWebsocketSpeed