Build a Python Audio Recorder with PyAudio: Step-by-Step Guide

Hello, I’m 🌑 (the dark side of the moon). This article shows how to use PyAudio in Python to create an audio recording and playback tool on Windows 10.

Application Platform

Windows 10

Python 3.7

Audio Recording Section

Audio recording works like video recording by capturing data frames. Install PyAudio with: pip install PyAudio If the installation fails, download the matching .whl file (e.g., PyAudio‑xx.whl) and install it with: pip install PyAudio-xx.whl Core recording code using a callback stream:

from pyaudio import PyAudio, paInt16, paContinue, paComplete

# Fixed parameters
chunk = 1024  # frames per buffer
format_sample = paInt16  # sample format
channels = 2  # 1=mono, 2=stereo
fps = 44100  # sampling rate

def callback(in_data, frame_count, time_info, status):
    """Recording callback"""
    wf.writeframes(in_data)
    if xx:  # when a certain condition is met
        return in_data, paContinue
    else:
        return in_data, paComplete

p = PyAudio()
stream = p.open(format=format_sample,
    channels=channels,
    rate=fps,
    frames_per_buffer=chunk,
    input=True,
    input_device_index=None,  # default device
    stream_callback=callback)
stream.start_stream()
while stream.is_active():
    time.sleep(0.1)  # sensitivity
stream.stop_stream()
stream.close()
p.terminate()

Save audio to a WAV file using the built‑in wave module:

import wave
wf = wave.open('test.wav', 'wb')
wf.setnchannels(channels)
wf.setsampwidth(p.get_sample_size(format_sample))
wf.setframerate(fps)

For better reuse, the above logic is wrapped into an AudioRecord class (partial example shown):

from pyaudio import PyAudio

class AudioRecord(PyAudio):
    def __init__(self):
        super().__init__()
        self.chunk = 1024
        self.format_sample = paInt16
        self.channels = 2
        self.fps = 44100
        self.input_dict = None
        self.output_dict = None
        self.stream = None
        self.filename = '~test.wav'
        self.duration = 0
        self.flag = False
        self.kill = False
    # ... additional methods omitted for brevity ...

Audio Playback Section

Playback code mirrors the recording code, using a callback to read frames from the WAV file:

wf = wave.open('test.wav', 'rb')

def callback(in_data, frame_count, time_info, status):
    data = wf.readframes(frame_count)
    return data, paContinue

stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
    channels=wf.getnchannels(),
    rate=wf.getframerate(),
    output=True,
    output_device_index=output_device_index,
    stream_callback=callback)
stream.start_stream()
while stream.is_active():
    time.sleep(0.1)

The tool supports both .wav and .mp3 formats for recording and playback.

GUI Window Attribute Code Section

To provide a user‑friendly interface, the script includes code for displaying audio duration and enumerating input/output devices:

# Audio duration
duration = wf.getnframes() / wf.getframerate()

# Enumerate devices
dev_info = self.get_device_info_by_index(i)
default_rate = int(dev_info['defaultSampleRate'])
if not dev_info['hostApi'] and default_rate == fps and '映射器' not in dev_info['name']:
    if dev_info['maxInputChannels']:
        print('Input device:', dev_info['name'])
    elif dev_info['maxOutputChannels']:
        print('Output device:', dev_info['name'])

pynput Keyboard Listener

The script uses pynput to listen for hotkeys that stop or cancel recording:

def hotkey(self):
    """Hotkey listener"""
    with keyboard.Listener(on_press=self.on_press) as listener:
        listener.join()

def on_press(self, key):
    try:
        if key.char == 't':  # stop recording and save
            self.flag = True
        elif key.char == 'k':  # cancel recording and delete file
            self.flag = True
            self.kill = True
    except Exception as e:
        print(e)

Summary

The article demonstrates how to record and play back audio on Windows using PyAudio, covering installation, stream callbacks, wave file handling, device enumeration, GUI integration, and keyboard hotkey control, providing a solid foundation for building more advanced audio tools.