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#!/usr/bin/python3
# -*- coding: utf-8 -*-
import numpy as np
from python_speech_features import sigproc
def calc_energy(signal, samplerate=16000, winlen=0.025, winstep=0.01):
"""
任意信号都可以看作是在电阻R=1 的电路上的电流 I. 则能量为 I^2
"""
signal = np.array(signal, dtype=np.float32)
power = np.square(signal)
# 分帧
frames = sigproc.framesig(power, winlen*samplerate, winstep*samplerate)
# 各帧能量总和.
energy = np.mean(frames, axis=-1)
return energy
def calc_zero_crossing_rate(signal, samplerate=16000, winlen=0.025, winstep=0.01):
"""过零率. """
signal = np.where(signal >= 0, 1, -1)
cross_zero = np.where(signal[1:] != signal[:-1], 1, 0)
frames = sigproc.framesig(cross_zero, winlen*samplerate, winstep*samplerate)
_, n = frames.shape
cross_zero_rate = np.mean(frames, axis=-1)
return cross_zero_rate
def detect_silence(signal, samplerate=16000, winlen=0.025, winstep=0.01, min_energy=0.01, min_cross_zero_rate=0.05):
"""静音段检测"""
energy = calc_energy(
signal=signal,
samplerate=samplerate,
winlen=winlen,
winstep=winstep,
)
cross_zero_rate = calc_zero_crossing_rate(
signal=signal,
samplerate=samplerate,
winlen=winlen,
winstep=winstep,
)
energy = energy < min_energy
cross_zero_rate = cross_zero_rate < min_cross_zero_rate
silence_signal = np.array(energy + cross_zero_rate, dtype=np.bool)
silence_signal = silence_signal.tolist()
frame_len = int(sigproc.round_half_up(winlen*samplerate))
frame_step = int(sigproc.round_half_up(winstep*samplerate))
silence_list = list()
last_s = False
for idx, s in enumerate(silence_signal):
if s is True:
if last_s is True:
silence = silence_list.pop(-1)
begin = silence[0]
count = silence[1]
silence_list.append([begin, count + 1])
else:
begin = frame_step * idx
silence_list.append([begin, 1])
last_s = s
result = list()
for silence in silence_list:
begin = silence[0]
count = silence[1]
end = begin + frame_step * (count - 1) + frame_len
result.append([begin, end])
return result
if __name__ == '__main__':
pass
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