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/*
* Copyright (c) 2008 MUSIC TECHNOLOGY GROUP (MTG)
* UNIVERSITAT POMPEU FABRA
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*! \file residual.c
* \brief main sms_residual() function
*/
#include "sms.h"
/*! \brief get the residual waveform
*
* \param sizeWindow size of buffers
* \param pSynthesis pointer to deterministic component
* \param pOriginal pointer to original waveform
* \param pResidual pointer to output residual waveform
* \param pWindow pointer to windowing array
* \return residual percentage (0 if residual was not large enough)
\todo why is residual energy percentage computed this way? should be optional and in a seperate function
*/
int sms_residual(int sizeWindow, sfloat *pSynthesis, sfloat *pOriginal, sfloat *pResidual, sfloat *pWindow)
{
static sfloat fResidualMag = 0.;
static sfloat fOriginalMag = 0.;
sfloat fScale = 1.;
sfloat fCurrentResidualMag = 0.;
sfloat fCurrentOriginalMag = 0.;
int i;
/* get residual */
for (i=0; i<sizeWindow; i++)
pResidual[i] = pOriginal[i] - pSynthesis[i];
/* get energy of residual */
for (i=0; i<sizeWindow; i++)
fCurrentResidualMag += (pResidual[i] * pResidual[i]);
/* if residual is big enough compute coefficients */
if (fCurrentResidualMag)
{
/* get energy of original */
for (i=0; i<sizeWindow; i++)
fCurrentOriginalMag += (pOriginal[i] * pOriginal[i]);
fOriginalMag = .5 * (fCurrentOriginalMag/sizeWindow + fOriginalMag);
fResidualMag = .5 * (fCurrentResidualMag/sizeWindow + fResidualMag);
/* scale residual if need to be */
if (fResidualMag > fOriginalMag)
{
fScale = fOriginalMag / fResidualMag;
for (i=0; i<sizeWindow; i++)
pResidual[i] *= fScale;
}
return fCurrentResidualMag / fCurrentOriginalMag;
}
return 0;
}
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