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diff --git a/sms/filters.c b/sms/filters.c
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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 filters.c
- * \brief various filters
- */
-
-#include "sms.h"
-
-/*! \brief coefficient for pre_emphasis filter */
-#define SMS_EMPH_COEF .9
-
-/* pre-emphasis filter function, it returns the filtered value
- *
- * sfloat fInput; sound sample
- */
-sfloat sms_preEmphasis(sfloat fInput, SMS_AnalParams *pAnalParams)
-{
- if(pAnalParams->preEmphasis)
- {
- sfloat fOutput = fInput - SMS_EMPH_COEF * pAnalParams->preEmphasisLastValue;
- pAnalParams->preEmphasisLastValue = fOutput;
- return fOutput;
- }
- return fInput;
-}
-
-/* de-emphasis filter function, it returns the filtered value
- *
- * sfloat fInput; sound input
- */
-sfloat sms_deEmphasis(sfloat fInput, SMS_SynthParams *pSynthParams)
-{
- if(pSynthParams->deEmphasis)
- {
- sfloat fOutput = fInput + SMS_EMPH_COEF * pSynthParams->deEmphasisLastValue;
- pSynthParams->deEmphasisLastValue = fInput;
- return fOutput;
- }
- return fInput;
-}
-
-/*! \brief function to implement a zero-pole filter
- *
- * \todo will forgetting to reset pD to zero at the beginning of a new analysis
- * (when there are multiple analyses within the life of one program)
- * cause problems?
- *
- * \param pFa pointer to numerator coefficients
- * \param pFb pointer to denominator coefficients
- * \param nCoeff number of coefficients
- * \param fInput input sample
- * \return value is the filtered sample
- */
-static sfloat ZeroPoleFilter(sfloat *pFa, sfloat *pFb, int nCoeff, sfloat fInput )
-{
- double fOut = 0;
- int iSection;
- static sfloat pD[5] = {0, 0, 0, 0, 0};
-
- pD[0] = fInput;
- for (iSection = nCoeff-1; iSection > 0; iSection--)
- {
- fOut = fOut + pFa[iSection] * pD[iSection];
- pD[0] = pD[0] - pFb[iSection] * pD[iSection];
- pD[iSection] = pD [iSection-1];
- }
- fOut = fOut + pFa[0] * pD[0];
- return (sfloat) fOut;
-}
-
-/*! \brief function to filter a waveform with a high-pass filter
- *
- * cutoff =1500 Hz
- *
- * \todo this filter only works on sample rates up to 48k?
- *
- * \param sizeResidual size of signal
- * \param pResidual pointer to residual signal
- * \param iSamplingRate sampling rate of signal
- */
-void sms_filterHighPass(int sizeResidual, sfloat *pResidual, int iSamplingRate)
-{
- /* cutoff 800Hz */
- static sfloat pFCoeff32k[10] = {0.814255, -3.25702, 4.88553, -3.25702,
- 0.814255, 1, -3.58973, 4.85128, -2.92405, 0.66301};
- static sfloat pFCoeff36k[10] = {0.833098, -3.33239, 4.99859, -3.33239,
- 0.833098, 1, -3.63528, 4.97089, -3.02934,0.694052};
- static sfloat pFCoeff40k[10] = {0.848475, -3.3939, 5.09085, -3.3939,
- 0.848475, 1, -3.67173, 5.068, -3.11597, 0.71991};
- static sfloat pFCoeff441k[10] = {0.861554, -3.44622, 5.16932, -3.44622,
- 0.861554, 1, -3.70223, 5.15023, -3.19013, 0.742275};
- static sfloat pFCoeff48k[10] = {0.872061, -3.48824, 5.23236, -3.48824,
- 0.872061, 1, -3.72641, 5.21605, -3.25002, 0.76049};
- sfloat *pFCoeff, fSample = 0;
- int i;
-
- if(iSamplingRate <= 32000)
- pFCoeff = pFCoeff32k;
- else if(iSamplingRate <= 36000)
- pFCoeff = pFCoeff36k;
- else if(iSamplingRate <= 40000)
- pFCoeff = pFCoeff40k;
- else if(iSamplingRate <= 44100)
- pFCoeff = pFCoeff441k;
- else
- pFCoeff = pFCoeff48k;
-
- for(i = 0; i < sizeResidual; i++)
- {
- /* try to avoid underflow when there is nothing to filter */
- if(i > 0 && fSample == 0 && pResidual[i] == 0)
- return;
-
- fSample = pResidual[i];
- pResidual[i] = ZeroPoleFilter (&pFCoeff[0], &pFCoeff[5], 5, fSample);
- }
-}
-
-/*! \brief a spectral filter
- *
- * filter each point of the current array by the surounding
- * points using a triangular window
- *
- * \param pFArray two dimensional input array
- * \param size1 vertical size of pFArray
- * \param size2 horizontal size of pFArray
- * \param pFOutArray output array of size size1
- */
-void sms_filterArray(sfloat *pFArray, int size1, int size2, sfloat *pFOutArray)
-{
- int i, j, iPoint, iFrame, size2_2 = size2-2, size2_1 = size2-1;
- sfloat *pFCurrentArray = pFArray + (size2_1) * size1;
- sfloat fVal, fWeighting, fTotalWeighting, fTmpVal;
-
- /* find the filtered envelope */
- for(i = 0; i < size1; i++)
- {
- fVal = pFCurrentArray[i];
- fTotalWeighting = 1;
- /* filter by the surrounding points */
- for(j = 1; j < (size2_2); j++)
- {
- fWeighting = (sfloat) size2 / (1+ j);
- /* filter on the vertical dimension */
- /* consider the lower points */
- iPoint = i - (size2_1) + j;
- if(iPoint >= 0)
- {
- fVal += pFCurrentArray[iPoint] * fWeighting;
- fTotalWeighting += fWeighting;
- }
- /* consider the higher points */
- iPoint = i + (size2_1) - j;
- if(iPoint < size1)
- {
- fVal += pFCurrentArray[iPoint] * fWeighting;
- fTotalWeighting += fWeighting;
- }
- /*filter on the horizontal dimension */
- /* consider the previous points */
- iFrame = j;
- fTmpVal = pFArray[iFrame*size1 + i];
- if(fTmpVal)
- {
- fVal += fTmpVal * fWeighting;
- fTotalWeighting += fWeighting;
- }
- }
- /* scale value by weighting */
- pFOutArray[i] = fVal / fTotalWeighting;
- }
-}
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