Python script for recording audio from speakers and streaming over RTSP

pawp_rtsp_stream.py

"""
A simple example of recording audio from speakers and streaming over RTSP protocol.
Requires pyaudiowpatch and RTSP server, e.g. https://github.com/bluenviron/mediamtx
"""

import pyaudiowpatch as pyaudio
import subprocess
import time
import wave

CHUNK_SIZE = 512

def main():
    with pyaudio.PyAudio() as p:
        """
        Create PyAudio instance via context manager.
        """
        try:
            # Get default WASAPI info
            wasapi_info = p.get_host_api_info_by_type(pyaudio.paWASAPI)
        except OSError:
            print("Looks like WASAPI is not available on the system. Exiting...")
            exit()
        
        # Get default WASAPI speakers
        default_speakers = p.get_device_info_by_index(wasapi_info["defaultOutputDevice"])
        
        if not default_speakers["isLoopbackDevice"]:
            for loopback in p.get_loopback_device_info_generator():
                """
                Try to find loopback device with same name(and [Loopback suffix]).
                Unfortunately, this is the most adequate way at the moment.
                """
                if default_speakers["name"] in loopback["name"]:
                    default_speakers = loopback
                    break
            else:
                print("Default loopback output device not found.\n\nRun `python -m pyaudiowpatch` to check available devices.\nExiting...\n")
                exit()
                
        print(f"Recording from: ({default_speakers['index']}){default_speakers['name']}")

        ffmpeg_command = [
            "ffmpeg",
            "-re",
            "-f", "s16le",
            "-ar", str(int(default_speakers["defaultSampleRate"])),
            "-ac", str(default_speakers["maxInputChannels"]),
            "-i", "-",
            "-c:a", "libvorbis",
            "-f", "rtsp",
            "-rtsp_transport", "tcp",
            "rtsp://localhost:8554/mystream"
        ]
        ffmpeg_process = subprocess.Popen(ffmpeg_command, stdin=subprocess.PIPE)
        
        def callback(in_data, frame_count, time_info, status):
            ffmpeg_process.stdin.write(in_data)
            return (in_data, pyaudio.paContinue)
        
        with p.open(format=pyaudio.paInt16,
                channels=default_speakers["maxInputChannels"],
                rate=int(default_speakers["defaultSampleRate"]),
                frames_per_buffer=CHUNK_SIZE,
                input=True,
                input_device_index=default_speakers["index"],
                stream_callback=callback
        ) as stream:
            print(f"Recording audio and streaming at rtsp://localhost:8554/mystream")
            while True:
                try:
                    time.sleep(1)
                except KeyboardInterrupt:
                    break

if __name__ == "__main__":
    main()