Recording audio only when someone is speaking is a powerful feature that can be used in various applications, from voice-activated assistants to saving storage space by eliminating silent periods. In this tutorial, you'll learn how to write Python code that starts recording when it detects speech and stops when silence is detected.
Prerequisites
Before diving in, ensure you have the following:
- Python 3.x installed on your system.
- Basic knowledge of Python.
- Familiarity with Python libraries like
pyaudio
,numpy
, andwebrtcvad
.
Step 1: Install Required Libraries ๐ฆ
Weโll be using the following libraries:
-
pyaudio
: For capturing audio from your microphone. -
webrtcvad
: For voice activity detection. -
numpy
: For handling audio data.
You can install them using pip:
pip install pyaudio webrtcvad numpy
Step 2: Setting Up Audio Stream ๐ง
First, letโs set up the audio stream to capture audio input from your microphone.
import pyaudio
# Audio configuration
FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 16000
CHUNK = 1024
# Initialize PyAudio
audio = pyaudio.PyAudio()
# Open stream
stream = audio.open(format=FORMAT,
channels=CHANNELS,
rate=RATE,
input=True,
frames_per_buffer=CHUNK)
Step 3: Implementing Voice Activity Detection (VAD) ๐ค
Weโll use the webrtcvad
library to detect when someone is speaking. The library can classify audio frames as speech or non-speech.
import webrtcvad
# Initialize VAD
vad = webrtcvad.Vad()
vad.set_mode(1) # 0: Aggressive filtering, 3: Less aggressive
def is_speech(frame, sample_rate):
return vad.is_speech(frame, sample_rate)
Step 4: Capturing and Processing Audio Frames ๐ผ
Now, let's continuously capture audio frames and check if they contain speech.
def record_audio():
frames = []
recording = False
print("Listening for speech...")
while True:
frame = stream.read(CHUNK)
if is_speech(frame, RATE):
if not recording:
print("Recording started.")
recording = True
frames.append(frame)
else:
if recording:
print("Silence detected, stopping recording.")
break
# Stop and close the stream
stream.stop_stream()
stream.close()
audio.terminate()
return frames
Step 5: Saving the Recorded Audio ๐พ
Finally, letโs save the recorded audio to a .wav
file.
import wave
def save_audio(frames, filename="output.wav"):
wf = wave.open(filename, 'wb')
wf.setnchannels(CHANNELS)
wf.setsampwidth(audio.get_sample_size(FORMAT))
wf.setframerate(RATE)
wf.writeframes(b''.join(frames))
wf.close()
# Example usage
frames = record_audio()
save_audio(frames)
print("Audio saved as output.wav")
Conclusion ๐
With just a few lines of code, youโve implemented a Python program that detects speech and records only the speaking portions, ignoring silence. This technique is especially useful for creating efficient voice-activated systems.
Feel free to experiment with the VAD aggressiveness and audio settings to suit your specific needs. Happy coding! ๐ฉโ๐ป๐จโ๐ป
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