84 lines
1.9 KiB
Python
84 lines
1.9 KiB
Python
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import sys
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import wave
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import numpy as np
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if len(sys.argv) != 2:
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print('Usage: {} multi.wav'.format(sys.argv[0]))
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sys.exit(1)
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multi = wave.open(sys.argv[1], 'rb')
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rate = multi.getframerate()
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channels = multi.getnchannels()
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if channels <= 1:
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sys.exit(1)
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N = rate
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window = np.hanning(N)
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interp = 4*8
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max_offset = int(rate * 0.1 / 340 * interp)
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def gcc_phat(sig, refsig, fs=1, max_tau=None, interp=16):
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'''
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This function computes the offset between the signal sig and the reference signal refsig
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using the Generalized Cross Correlation - Phase Transform (GCC-PHAT)method.
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'''
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# make sure the length for the FFT is larger or equal than len(sig) + len(refsig)
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n = sig.shape[0] + refsig.shape[0]
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# Generalized Cross Correlation Phase Transform
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SIG = np.fft.rfft(sig, n=n)
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REFSIG = np.fft.rfft(refsig, n=n)
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R = SIG * np.conj(REFSIG)
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#R /= np.abs(R)
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cc = np.fft.irfft(R, n=(interp * n))
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max_shift = int(interp * n / 2)
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if max_tau:
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max_shift = np.minimum(int(interp * fs * max_tau), max_shift)
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cc = np.concatenate((cc[-max_shift:], cc[:max_shift+1]))
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# find max cross correlation index
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shift = np.argmax(np.abs(cc)) - max_shift
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tau = shift / float(interp * fs)
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return tau, cc
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print(multi.getsampwidth())
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while True:
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data = multi.readframes(N)
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if len(data) != multi.getsampwidth() * N * channels:
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print("done")
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break
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if multi.getsampwidth() == 2:
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data = np.fromstring(data, dtype='int16')
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else:
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data = np.fromstring(data, dtype='int32')
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ref_buf = data[0::channels]
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offsets = []
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for ch in range(1, channels):
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sig_buf = data[ch::channels]
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tau, _ = gcc_phat(sig_buf * window, ref_buf * window, fs=1, max_tau=max_offset, interp=interp)
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# tau, _ = gcc_phat(sig_buf, ref_buf, fs=rate, max_tau=1)
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offsets.append(tau)
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print(offsets)
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print(multi.getframerate())
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multi.close()
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