In [1]:

    

# E4896_L06_lpc_diary
%pylab inline


    

    




Populating the interactive namespace from numpy and matplotlib

In [4]:

    

import numpy as np
import scipy
import librosa

from IPython.lib.display import Audio

import zplane
import lpc


    

In [12]:

    

d, sr = librosa.load('sm1_cln.wav', sr=8000)
print d.shape
print sr
Audio(d, rate=sr*2)


    

    




(27802,)
8000






    
Out[12]:





                
              

In [13]:

    

_ = specgram(d, 256, sr*2)


    

In [7]:

    

win = 256
dd = d[15000 + np.arange(win)]
wdd = np.hanning(win)*dd
plt.figure(figsize=(10, 4))
plot(np.arange(win), dd, np.arange(win), wdd)


    

    
Out[7]:





[<matplotlib.lines.Line2D at 0x113381e90>,
 <matplotlib.lines.Line2D at 0x113391150>]






    

In [8]:

    

WDD = np.abs(np.fft.fft(wdd))[:129]
plt.figure(figsize=(10, 4))
plot(np.arange(129)*sr/256, 20*np.log10(WDD))


    

    
Out[8]:





[<matplotlib.lines.Line2D at 0x1133b86d0>]






    

In [34]:

    

order = 96
rxx = np.correlate(wdd, wdd, 'full')
# Keep only for lags >= 0.
rxx = rxx[255:]
plt.figure(figsize=(10, 4))
plot(rxx)


    

    
Out[34]:





[<matplotlib.lines.Line2D at 0x114bd4bd0>]






    

In [35]:

    

coeffs = np.dot(np.linalg.inv(scipy.linalg.toeplitz(rxx[:order])), rxx[1 : order + 1])
aa = np.hstack([1, -coeffs])
[W, H] = scipy.signal.freqz(1, aa)
plt.figure(figsize=(10, 4))
plot(W*sr/2/np.pi, 20*np.log10(np.abs(H)), np.arange(129)*sr/256, 20*np.log10(WDD)+15)


    

    
Out[35]:





[<matplotlib.lines.Line2D at 0x11489c9d0>,
 <matplotlib.lines.Line2D at 0x11489cbd0>]






    

In [36]:

    

rdd = scipy.signal.lfilter(aa, 1 ,wdd)
plt.figure(figsize=(10, 4))
plot(np.arange(256), wdd, np.arange(256), rdd*2)


    

    
Out[36]:





[<matplotlib.lines.Line2D at 0x1132ae310>,
 <matplotlib.lines.Line2D at 0x1132aeb50>]






    

In [37]:

    

_ = zplane.zplane(np.roots([]), np.roots(aa))


    

In [57]:

    

[a, g, e] = lpc.lpcfit(d, 8)


    

In [46]:

    

print a.shape


    

    




(217, 97)

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rd = lpc.lpcsynth(a, g, 64)
plt.figure(figsize=(10, 4))
plot(rd)


    

    
Out[49]:





[<matplotlib.lines.Line2D at 0x11756df10>]






    

In [50]:

    

plt.figure(figsize=(10, 4))
_ = specgram(rd, Fs=sr)


    

In [28]:

    

plt.figure(figsize=(10, 4))
_ = specgram(rd, Fs=sr)


    

In [51]:

    

Audio(rd, rate=sr)


    

    
Out[51]:





                
              

In [38]:

    

reload(lpc)


    

    
Out[38]:





<module 'lpc' from 'lpc.py'>

In [58]:

    

bh = lpc.lpcBHenc(e)


    

In [59]:

    

plt.figure(figsize=(10, 4))
print(bh.shape)
plot(bh)


    

    




(217,)






    
Out[59]:





[<matplotlib.lines.Line2D at 0x115accf10>]






    

In [60]:

    

er = lpc.lpcBHdec(bh)


    

In [61]:

    

Audio(er, rate=sr)


    

    
Out[61]:





                
              

In [62]:

    

rde = lpc.lpcsynth(a, g, er)
Audio(rde, rate=sr)


    

    
Out[62]:





                
              

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