LPC avec Scipy

Après avoir acquis le coefficient AR par LPC, j'ai essayé de le piloter avec du bruit blanc. J'ai l'impression que ma voix est devenue comme un robot (?). De plus, si vous modifiez le bruit de conduite, vous devriez obtenir une qualité de voix différente.

lpc.py

#!/usr/bin/env python

import sys
import wave
import urllib2
import getopt
import scipy as sp
import matplotlib.pyplot as plt
from scipy import linalg, signal
from scikits.talkbox.linpred.levinson_lpc import lpc

if __name__ == "__main__":
    optlist, argv = getopt.getopt( sys.argv[1:], 's:l:o:w:')

    frameLength = 512
    stepWidth = 256
    lpcOrder = 32
    chunk = 44100 * 5
    for opt, val in optlist:
        if( opt == '-s' ):
            chunk = int( val )
        elif( opt == '-w' ):
            stepWidth = int( val )
        elif( opt == '-l'):
            frameLength = int( val )
        elif( opt == '-o' ):
            lpcOrder = int( val )

    argc = len( argv )
    if( 0 < argc ):
        if( argc == 2 ):
            inFileName, outFileName = argv
        elif( argc == 1 ):
            inFileName = argv[0]
            outFileName = 'out.wav'
        wo = wave.open( inFileName, 'rb' )
    else:
        outFileName = 'out.wav'
        url = 'http://www.it.ice.uec.ac.jp/SRV-DB/archive/HENSHU00_PF00/HENSHU00_PF00_0951.wav'
        wo = wave.openfp( urllib2.urlopen( url ).fp,  'rb' )

    data = sp.fromstring( wo.readframes( chunk ), sp.int16 )
    blockData = sp.linalg.toeplitz( data[ frameLength:], data[:frameLength] )[::stepWidth, :]

    lpcCoef, lpcError, k = lpc( blockData,  lpcOrder )
    excitationSignal = sp.random.randn( frameLength )

    rows, cols = lpcCoef.shape
    responseSignal = sp.zeros( ( rows,  frameLength ) )
    synthesisSignal = sp.array( [0] * ( rows  * stepWidth + frameLength ) )
    weight = sp.sin( 2 * sp.pi * sp.r_[0:frameLength] / frameLength )
    for i in range( rows ):
        G = sp.sqrt( lpcError[ i ] )
        responseSignal[i, :] = sp.signal.lfilter( [G], lpcCoef[ i, :], excitationSignal )
        synthesisSignal[ i * stepWidth:i * stepWidth + frameLength ] +=  weight * responseSignal[ i, :]

    outputSignal = sp.int16( synthesisSignal ).tostring()
    wo = wave.open( outFileName, 'wb')
    params = ( 1, 2, 44100, len( synthesisSignal),'NONE','none')
    wo.setparams( params )
    wo.writeframes( outputSignal )
    wo.close()