python語音信號處理-加窗、分幀、STFT

其實這個可以用STFT可以用librosa來進行處理。

from __future__ import division
from scikits.talkbox import segment_axis
import numpy as np
import soundfile as sf

def readwav(fn):
    signal, sampleRate = sf.read(fn)
    signal -= np.mean(signal)
    signal /= np.max(np.abs(signal))# Normalize the amplitude
    nframes = len(signal)
    return signal, sampleRate, nframes

# smoother version of hanning window
def sqrt_hann(M):
    return np.sqrt(np.hanning(M))

# signal: 1D array, returns a 2D complex array
def pro_signal(signal, window = 'hanning', frame_len = 1024, overlap = 512):
    if window == 'hanning':
        # w = np.hanning(frame_len)
        w = sqrt_hann(frame_len)
    else:
        w = window
    y = segment_axis(signal, frame_len , overlap = overlap, end = 'cut')# use cut instead of pad
    y = w * y
    return y

# signal is a 2d matrix, n_frames * frame_len
# returns a 2d matrix, n_frames * frame_len /2 + 1
def stft(signal):
    out = np.array([np.fft.rfft(signal[i]) for i in xrange(signal.shape[0])])
    return out

# Load the signal
fn = 'lullaby.wav'
signal, sampleRate, nframes = readwav(fn)
print sampleRate, nframes
snd = pro_signal(signal, frame_len = 1024, overlap = 512)
out = stft(snd)
print out.shape