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CodeLib → Programming aids → Python
#!/usr/bin/env python3
import pyaudio
import numpy as np
CHUNK = 2*4096 # number of data points to read at a time
RATE = 48000 # time resolution of the recording device (Hz)
DEVICE = 0 # default output device
TARGET_FREQ = 440 # in Hz
p = pyaudio.PyAudio()
stream=p.open(format=pyaudio.paInt16,channels=1,rate=RATE,input=True, input_device_index=DEVICE,
frames_per_buffer=CHUNK)
col_target = []
col_other = []
while True:
indata = np.fromstring(stream.read(CHUNK),dtype=np.int16)
fftData=np.fft.fft(indata)
freqs = np.fft.fftfreq(fftData.size)
magnitudes = fftData[1:int(fftData.size/2)]
# Find out volume of target frequency
idx = (np.abs(freqs-TARGET_FREQ/RATE)).argmin()
volume_target = np.sum(np.abs(magnitudes[int(idx-1):int(idx+1)])) / 3
# Find out the general volume
volume_other = np.mean(np.abs(magnitudes))
# Filter peaks
col_other.append(volume_other)
while len(col_other) > 10:
col_other.pop(0)
volume_other = (np.sum(col_other) + 5*volume_other) / 15
col_target.append(volume_target)
while len(col_target) > 10:
col_target.pop(0)
volume_target = (np.sum(col_target) + 5*volume_target) / 15
# Check ratio
print(volume_target/volume_other)
stream.close()
p.terminate()Daniel Marschall
ViaThinkSoft Co-Founder
ViaThinkSoft Co-Founder