Transcribe System Audio in Real-Time (macOS)

1
import pyaudio
2
import websocket
3
import json
4
import threading
5
import time
6
from urllib.parse import urlencode
7
from datetime import datetime
8
9
# --- Configuration ---
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YOUR_API_KEY = "YOUR_API_KEY"  # Replace with your actual API key
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12
CONNECTION_PARAMS = {
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    "sample_rate": 16000,
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    "format_turns": True,  # Request formatted final transcripts
15
}
16
API_ENDPOINT_BASE_URL = "wss://streaming.assemblyai.com/v3/ws"
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API_ENDPOINT = f"{API_ENDPOINT_BASE_URL}?{urlencode(CONNECTION_PARAMS)}"
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# Audio Configuration
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FRAMES_PER_BUFFER = 800  # 50ms of audio (0.05s * 16000Hz)
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SAMPLE_RATE = CONNECTION_PARAMS["sample_rate"]
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CHANNELS = 1
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FORMAT = pyaudio.paInt16
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# Global variables for audio stream and websocket
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audio = None
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stream = None
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ws_app = None
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audio_thread = None
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stop_event = threading.Event()  # To signal the audio thread to stop
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# WAV recording variables
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recorded_frames = []  # Store audio frames for WAV file
34
recording_lock = threading.Lock()  # Thread-safe access to recorded_frames
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# --- BlackHole Device Detection ---
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def get_blackhole_device_index():
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    """Find BlackHole audio device index."""
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    p = pyaudio.PyAudio()
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    blackhole_index = None
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    print("Available audio devices:")
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    for i in range(p.get_device_count()):
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        dev_info = p.get_device_info_by_index(i)
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        print(f"  {i}: {dev_info['name']} (inputs: {dev_info['maxInputChannels']})")
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        if str(dev_info['name']).startswith('BlackHole') and dev_info['maxInputChannels'] > 0:
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            blackhole_index = i
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            print(f"  -> Found BlackHole device at index {i}")
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    p.terminate()
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    return blackhole_index
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# --- WebSocket Event Handlers ---
57
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def on_open(ws):
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    """Called when the WebSocket connection is established."""
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    print("WebSocket connection opened.")
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    print(f"Connected to: {API_ENDPOINT}")
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    # Start sending audio data in a separate thread
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    def stream_audio():
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        global stream
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        print("Starting audio streaming...")
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        while not stop_event.is_set():
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            try:
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                audio_data = stream.read(FRAMES_PER_BUFFER, exception_on_overflow=False)
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                # Store audio data for WAV recording
72
                with recording_lock:
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                    recorded_frames.append(audio_data)
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                # Send audio data as binary message
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                ws.send(audio_data, websocket.ABNF.OPCODE_BINARY)
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            except Exception as e:
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                print(f"Error streaming audio: {e}")
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                # If stream read fails, likely means it's closed, stop the loop
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                break
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        print("Audio streaming stopped.")
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    global audio_thread
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    audio_thread = threading.Thread(target=stream_audio)
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    audio_thread.daemon = (
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        True  # Allow main thread to exit even if this thread is running
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    )
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    audio_thread.start()
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def on_message(ws, message):
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    try:
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        data = json.loads(message)
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        msg_type = data.get('type')
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        if msg_type == "Begin":
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            session_id = data.get('id')
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            expires_at = data.get('expires_at')
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            print(f"\nSession began: ID={session_id}, ExpiresAt={datetime.fromtimestamp(expires_at)}")
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        elif msg_type == "Turn":
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            transcript = data.get('transcript', '')
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            if data.get('end_of_turn'):
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                print('\r' + ' ' * 80 + '\r', end='')
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                print(transcript)
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            else:
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                print(f"\r{transcript}", end='')
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        elif msg_type == "Termination":
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            audio_duration = data.get('audio_duration_seconds', 0)
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            session_duration = data.get('session_duration_seconds', 0)
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            print(f"\nSession Terminated: Audio Duration={audio_duration}s, Session Duration={session_duration}s")
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    except json.JSONDecodeError as e:
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        print(f"Error decoding message: {e}")
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    except Exception as e:
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        print(f"Error handling message: {e}")
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def on_error(ws, error):
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    """Called when a WebSocket error occurs."""
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    print(f"\nWebSocket Error: {error}")
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    # Attempt to signal stop on error
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    stop_event.set()
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def on_close(ws, close_status_code, close_msg):
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    """Called when the WebSocket connection is closed."""
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    print(f"\nWebSocket Disconnected: Status={close_status_code}, Msg={close_msg}")
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    # Ensure audio resources are released
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    global stream, audio
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    stop_event.set()  # Signal audio thread just in case it's still running
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    if stream:
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        if stream.is_active():
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            stream.stop_stream()
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        stream.close()
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        stream = None
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    if audio:
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        audio.terminate()
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        audio = None
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    # Try to join the audio thread to ensure clean exit
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    if audio_thread and audio_thread.is_alive():
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        audio_thread.join(timeout=1.0)
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# --- Main Execution ---
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def run():
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    global audio, stream, ws_app
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    # Find BlackHole device
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    blackhole_index = get_blackhole_device_index()
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    if blackhole_index is None:
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        print("Error: BlackHole audio device not found!")
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        print("Please install BlackHole from https://existential.audio/blackhole/")
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        return
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    # Initialize PyAudio
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    audio = pyaudio.PyAudio()
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    # Open Blackhole audio stream
159
    try:
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        stream = audio.open(
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            input=True,
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            input_device_index=blackhole_index,  # Use BlackHole device
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            frames_per_buffer=FRAMES_PER_BUFFER,
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            channels=CHANNELS,
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            format=FORMAT,
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            rate=SAMPLE_RATE,
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        )
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        print(f"BlackHole audio stream opened successfully (device index: {blackhole_index}).")
170
        print("Now capturing system audio through BlackHole. Press Ctrl+C to stop.")
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        print("Make sure audio is routed through BlackHole for transcription.")
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    except Exception as e:
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        print(f"Error opening Blackhole audio stream: {e}")
175
        if audio:
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            audio.terminate()
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        return  # Exit if blackhole cannot be opened
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    # Create WebSocketApp
180
    ws_app = websocket.WebSocketApp(
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        API_ENDPOINT,
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        header={"Authorization": YOUR_API_KEY},
183
        on_open=on_open,
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        on_message=on_message,
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        on_error=on_error,
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        on_close=on_close,
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    )
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    # Run WebSocketApp in a separate thread to allow main thread to catch KeyboardInterrupt
190
    ws_thread = threading.Thread(target=ws_app.run_forever)
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    ws_thread.daemon = True
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    ws_thread.start()
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    try:
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        # Keep main thread alive until interrupted
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        while ws_thread.is_alive():
197
            time.sleep(0.1)
198
    except KeyboardInterrupt:
199
        print("\nCtrl+C received. Stopping...")
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        stop_event.set()  # Signal audio thread to stop
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        # Send termination message to the server
203
        if ws_app and ws_app.sock and ws_app.sock.connected:
204
            try:
205
                terminate_message = {"type": "Terminate"}
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                print(f"Sending termination message: {json.dumps(terminate_message)}")
207
                ws_app.send(json.dumps(terminate_message))
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                # Give a moment for messages to process before forceful close
209
                time.sleep(5)
210
            except Exception as e:
211
                print(f"Error sending termination message: {e}")
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        # Close the WebSocket connection (will trigger on_close)
214
        if ws_app:
215
            ws_app.close()
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        # Wait for WebSocket thread to finish
218
        ws_thread.join(timeout=2.0)
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    except Exception as e:
221
        print(f"\nAn unexpected error occurred: {e}")
222
        stop_event.set()
223
        if ws_app:
224
            ws_app.close()
225
        ws_thread.join(timeout=2.0)
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    finally:
228
        # Final cleanup (already handled in on_close, but good as a fallback)
229
        if stream and stream.is_active():
230
            stream.stop_stream()
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        if stream:
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            stream.close()
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        if audio:
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            audio.terminate()
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        print("Cleanup complete. Exiting.")
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if __name__ == "__main__":
238
    run()

1
import pyaudio
2
import websocket
3
import json
4
import threading
5
import time
6
from urllib.parse import urlencode
7
from datetime import datetime
8
9
YOUR_API_KEY = "YOUR-API-KEY"  # Replace with your actual API key

1
CONNECTION_PARAMS = {
2
    "sample_rate": 16000,
3
    "format_turns": True,  # Request formatted final transcripts
4
}
5
API_ENDPOINT_BASE_URL = "wss://streaming.assemblyai.com/v3/ws"
6
API_ENDPOINT = f"{API_ENDPOINT_BASE_URL}?{urlencode(CONNECTION_PARAMS)}"
7
8
# Audio Configuration
9
FRAMES_PER_BUFFER = 800  # 50ms of audio (0.05s * 16000Hz)
10
SAMPLE_RATE = CONNECTION_PARAMS["sample_rate"]
11
CHANNELS = 1
12
FORMAT = pyaudio.paInt16
13
14
# Global variables for audio stream and websocket
15
audio = None
16
stream = None
17
ws_app = None
18
audio_thread = None
19
stop_event = threading.Event()  # To signal the audio thread to stop
20
21
# WAV recording variables
22
recorded_frames = []  # Store audio frames for WAV file
23
recording_lock = threading.Lock()  # Thread-safe access to recorded_frames

1
def get_blackhole_device_index():
2
    """Find BlackHole audio device index."""
3
    p = pyaudio.PyAudio()
4
    blackhole_index = None
5
6
    print("Available audio devices:")
7
8
    for i in range(p.get_device_count()):
9
        dev_info = p.get_device_info_by_index(i)
10
        print(f"  {i}: {dev_info['name']} (inputs: {dev_info['maxInputChannels']})")
11
12
        if str(dev_info['name']).startswith('BlackHole') and dev_info['maxInputChannels'] > 0:
13
            blackhole_index = i
14
            print(f"  -> Found BlackHole device at index {i}")
15
16
    p.terminate()
17
    return blackhole_index

1
def on_open(ws):
2
    """Called when the WebSocket connection is established."""
3
    print("WebSocket connection opened.")
4
    print(f"Connected to: {API_ENDPOINT}")
5
6
    # Start sending audio data in a separate thread
7
    def stream_audio():
8
        global stream
9
        print("Starting audio streaming...")
10
        while not stop_event.is_set():
11
            try:
12
                audio_data = stream.read(FRAMES_PER_BUFFER, exception_on_overflow=False)
13
14
                # Store audio data for WAV recording
15
                with recording_lock:
16
                    recorded_frames.append(audio_data)
17
18
                # Send audio data as binary message
19
                ws.send(audio_data, websocket.ABNF.OPCODE_BINARY)
20
            except Exception as e:
21
                print(f"Error streaming audio: {e}")
22
                # If stream read fails, likely means it's closed, stop the loop
23
                break
24
        print("Audio streaming stopped.")
25
26
    global audio_thread
27
    audio_thread = threading.Thread(target=stream_audio)
28
    audio_thread.daemon = (
29
        True  # Allow main thread to exit even if this thread is running
30
    )
31
    audio_thread.start()

1
def on_message(ws, message):
2
    try:
3
        data = json.loads(message)
4
        msg_type = data.get('type')
5
6
        if msg_type == "Begin":
7
            session_id = data.get('id')
8
            expires_at = data.get('expires_at')
9
            print(f"\nSession began: ID={session_id}, ExpiresAt={datetime.fromtimestamp(expires_at)}")
10
        elif msg_type == "Turn":
11
            transcript = data.get('transcript', '')
12
            if data.get('end_of_turn'):
13
                print('\r' + ' ' * 80 + '\r', end='')
14
                print(transcript)
15
            else:
16
                print(f"\r{transcript}", end='')
17
        elif msg_type == "Termination":
18
            audio_duration = data.get('audio_duration_seconds', 0)
19
            session_duration = data.get('session_duration_seconds', 0)
20
            print(f"\nSession Terminated: Audio Duration={audio_duration}s, Session Duration={session_duration}s")
21
    except json.JSONDecodeError as e:
22
        print(f"Error decoding message: {e}")
23
    except Exception as e:
24
        print(f"Error handling message: {e}")

1
def on_close(ws, close_status_code, close_msg):
2
    """Called when the WebSocket connection is closed."""
3
    print(f"\nWebSocket Disconnected: Status={close_status_code}, Msg={close_msg}")
4
5
    # Ensure audio resources are released
6
    global stream, audio
7
    stop_event.set()  # Signal audio thread just in case it's still running
8
9
    if stream:
10
        if stream.is_active():
11
            stream.stop_stream()
12
        stream.close()
13
        stream = None
14
    if audio:
15
        audio.terminate()
16
        audio = None
17
    # Try to join the audio thread to ensure clean exit
18
    if audio_thread and audio_thread.is_alive():
19
        audio_thread.join(timeout=1.0)

1
def on_error(ws, error):
2
    """Called when a WebSocket error occurs."""
3
    print(f"\nWebSocket Error: {error}")
4
    # Attempt to signal stop on error
5
    stop_event.set()

1
def run():
2
    global audio, stream, ws_app
3
4
    # Find BlackHole device index
5
    blackhole_index = get_blackhole_device_index()
6
7
    if blackhole_index is None:
8
        print("Error: BlackHole audio device not found!")
9
        print("Please install BlackHole from https://existential.audio/blackhole/")
10
        return
11
12
    # Initialize PyAudio
13
    audio = pyaudio.PyAudio()
14
15
    # Open Blackhole audio stream
16
    try:
17
        stream = audio.open(
18
            input=True,
19
            input_device_index=blackhole_index,  # Use BlackHole device
20
            frames_per_buffer=FRAMES_PER_BUFFER,
21
            channels=CHANNELS,
22
            format=FORMAT,
23
            rate=SAMPLE_RATE,
24
        )
25
26
        print(f"BlackHole audio stream opened successfully (device index: {blackhole_index}).")
27
        print("Now capturing system audio through BlackHole. Press Ctrl+C to stop.")
28
        print("Make sure audio is routed through BlackHole for transcription.")
29
30
    except Exception as e:
31
        print(f"Error opening Blackhole audio stream: {e}")
32
        if audio:
33
            audio.terminate()
34
        return  # Exit if blackhole cannot be opened
35
36
    # Create WebSocketApp
37
    ws_app = websocket.WebSocketApp(
38
        API_ENDPOINT,
39
        header={"Authorization": YOUR_API_KEY},
40
        on_open=on_open,
41
        on_message=on_message,
42
        on_error=on_error,
43
        on_close=on_close,
44
    )
45
46
    # Run WebSocketApp in a separate thread to allow main thread to catch KeyboardInterrupt
47
    ws_thread = threading.Thread(target=ws_app.run_forever)
48
    ws_thread.daemon = True
49
    ws_thread.start()
50
51
    try:
52
        # Keep main thread alive until interrupted
53
        while ws_thread.is_alive():
54
            time.sleep(0.1)
55
    except KeyboardInterrupt:
56
        print("\nCtrl+C received. Stopping...")
57
        stop_event.set()  # Signal audio thread to stop
58
59
        # Send termination message to the server
60
        if ws_app and ws_app.sock and ws_app.sock.connected:
61
            try:
62
                terminate_message = {"type": "Terminate"}
63
                print(f"Sending termination message: {json.dumps(terminate_message)}")
64
                ws_app.send(json.dumps(terminate_message))
65
                # Give a moment for messages to process before forceful close
66
                time.sleep(5)
67
            except Exception as e:
68
                print(f"Error sending termination message: {e}")
69
70
        # Close the WebSocket connection (will trigger on_close)
71
        if ws_app:
72
            ws_app.close()
73
74
        # Wait for WebSocket thread to finish
75
        ws_thread.join(timeout=2.0)
76
77
    except Exception as e:
78
        print(f"\nAn unexpected error occurred: {e}")
79
        stop_event.set()
80
        if ws_app:
81
            ws_app.close()
82
        ws_thread.join(timeout=2.0)
83
84
    finally:
85
        # Final cleanup (already handled in on_close, but good as a fallback)
86
        if stream and stream.is_active():
87
            stream.stop_stream()
88
        if stream:
89
            stream.close()
90
        if audio:
91
            audio.terminate()
92
        print("Cleanup complete. Exiting.")
93
94
if __name__ == "__main__":
95
    run()