Streaming Migration Guide: Universal Streaming to Universal-3 Pro Streaming

import pyaudio
import websocket
import json
import threading
import time
from urllib.parse import urlencode

YOUR_API_KEY = "<YOUR_API_KEY>"

CONNECTION_PARAMS = {
    "sample_rate": 16000,
    "speech_model": "u3-rt-pro",
}
API_ENDPOINT_BASE_URL = "wss://streaming.assemblyai.com/v3/ws"
API_ENDPOINT = f"{API_ENDPOINT_BASE_URL}?{urlencode(CONNECTION_PARAMS)}"

FRAMES_PER_BUFFER = 800
SAMPLE_RATE = CONNECTION_PARAMS["sample_rate"]
CHANNELS = 1
FORMAT = pyaudio.paInt16

audio = None
stream = None
ws_app = None
audio_thread = None
stop_event = threading.Event()

def on_open(ws):
    print("WebSocket connection opened.")
    def stream_audio():
        global stream
        while not stop_event.is_set():
            try:
                audio_data = stream.read(FRAMES_PER_BUFFER, exception_on_overflow=False)
                ws.send(audio_data, websocket.ABNF.OPCODE_BINARY)
            except Exception as e:
                print(f"Error streaming audio: {e}")
                break

    global audio_thread
    audio_thread = threading.Thread(target=stream_audio)
    audio_thread.daemon = True
    audio_thread.start()

def on_message(ws, message):
    try:
        data = json.loads(message)
        msg_type = data.get("type")

        if msg_type == "Begin":
            print(f"Session began: ID={data.get('id')}")
        elif msg_type == "Turn":
            transcript = data.get("transcript", "")
            end_of_turn = data.get("end_of_turn", False)
            if end_of_turn:
                print(f"\r{' ' * 80}\r{transcript}")
            else:
                print(f"\r{transcript}", end="")
        elif msg_type == "Termination":
            print(f"\nSession terminated: {data.get('audio_duration_seconds', 0)}s of audio")
    except Exception as e:
        print(f"Error handling message: {e}")

def on_error(ws, error):
    print(f"\nWebSocket Error: {error}")
    stop_event.set()

def on_close(ws, close_status_code, close_msg):
    print(f"\nWebSocket Disconnected: Status={close_status_code}")
    global stream, audio
    stop_event.set()
    if stream:
        if stream.is_active():
            stream.stop_stream()
        stream.close()
    if audio:
        audio.terminate()

def run():
    global audio, stream, ws_app

    audio = pyaudio.PyAudio()
    stream = audio.open(
        input=True,
        frames_per_buffer=FRAMES_PER_BUFFER,
        channels=CHANNELS,
        format=FORMAT,
        rate=SAMPLE_RATE,
    )
    print("Speak into your microphone. Press Ctrl+C to stop.")

    ws_app = websocket.WebSocketApp(
        API_ENDPOINT,
        header={"Authorization": YOUR_API_KEY},
        on_open=on_open,
        on_message=on_message,
        on_error=on_error,
        on_close=on_close,
    )

    ws_thread = threading.Thread(target=ws_app.run_forever)
    ws_thread.daemon = True
    ws_thread.start()

    try:
        while ws_thread.is_alive():
            time.sleep(0.1)
    except KeyboardInterrupt:
        print("\nStopping...")
        stop_event.set()
        if ws_app and ws_app.sock and ws_app.sock.connected:
            ws_app.send(json.dumps({"type": "Terminate"}))
            time.sleep(2)
        if ws_app:
            ws_app.close()
        ws_thread.join(timeout=2.0)

if __name__ == "__main__":
    run()