195 lines
4.4 KiB
C++
195 lines
4.4 KiB
C++
/******************************************************************************
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* sigproc.cpp *
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*-------------*
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*
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*------------------------------------------------------------------------------
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* Copyright (C) 1999 Entropic, Inc
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* Copyright (C) 2000 Microsoft Corporation Date: 03/02/00
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* All Rights Reserved
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*
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********************************************************************* PACOG ***/
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#include "sigprocInt.h"
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#define PREEMP_FACTOR 0.97F
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/*****************************************************************************
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* Cepstrum *
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*----------*
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* Description:
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* compute lpc ceptrum form lpc coefficients
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*
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******************************************************************* PACOG ***/
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double* Cepstrum(double *pdData, int iNumData, int iLpcOrder, int iCepOrder)
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{
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double* pdCepCoef = 0;
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double* pdWindow = 0;
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double* pdLpcCoef = 0;
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assert(iLpcOrder > 0);
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assert(iCepOrder > 0);
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// get lpc coef
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pdWindow = ComputeWindow (WINDOW_HAMM, iNumData, false);
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if (!pdWindow)
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{
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return 0;
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}
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for (int i=1; i<iNumData; i++)
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{
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pdWindow[i] *= pdData[i] - PREEMP_FACTOR * pdData[i-1];
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}
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pdLpcCoef = GetDurbinCoef (pdWindow , iNumData, iLpcOrder, LPC_ALFA, NULL);
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if ((pdCepCoef = new double[iCepOrder]) == 0)
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{
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return 0;
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}
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Alfa2Cepstrum (pdLpcCoef, iLpcOrder, pdCepCoef, iCepOrder);
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delete[] pdWindow;
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delete[] pdLpcCoef;
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return pdCepCoef;
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}
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/*****************************************************************************
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* Alfa2Cepstrum *
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*---------------*
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* Description:
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* compute lpc cepstrum from lpc coefficients
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* a = alfa (lpc) coefs, input
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* p = order of lpc analysis
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* c = cepstrum coefs, output
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* n = order of cepstral analysis
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******************************************************************* PACOG ***/
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void Alfa2Cepstrum (double* pdAlfa, int iNumAlfa, double* pdCepstrum, int iNumCepstrum)
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{
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double dAux;
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int k;
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pdCepstrum[0] = -pdAlfa[0];
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for (int i = 1; i < iNumCepstrum; i++)
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{
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if (i<iNumAlfa)
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{
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pdCepstrum[i] = -pdAlfa[i];
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}
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else
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{
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pdCepstrum[i] = 0.0;
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}
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dAux = 0.0;
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for (k = 1; k<=i && k<=iNumAlfa; k++)
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{
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dAux += ((double)(i+1-k)/(double)(i+1)) * pdCepstrum[i-k] * pdAlfa[k-1];
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}
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pdCepstrum[i] -= dAux;
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}
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}
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/*****************************************************************************
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* EuclideanDist *
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*---------------*
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* Description:
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*
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******************************************************************* PACOG ***/
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double EuclideanDist (double c1[], double c2[], int iLen)
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{
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double dDist = 0.0;
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for (int i = 0; i < iLen; i++)
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{
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dDist += (c1[i] - c2[i]) * (c1[i] - c2[i]);
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}
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return dDist;
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}
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/*****************************************************************************
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* Energy *
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*--------*
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* Description:
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* Compute the time-weighted RMS of a size segment of data. The data
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* is weighted by a window of type w_type before RMS computation. w_type
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* is decoded above in window().
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******************************************************************* PACOG ***/
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double Energy (double* pdData, int iNumData, int iWindType)
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{
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static int iWindLen = 0;
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static double *pdWindow = 0;
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double dWData;
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double dSum = 0.0;
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assert (pdData);
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if (iWindLen != iNumData)
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{
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if (pdWindow)
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{
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delete[] pdWindow;
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}
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pdWindow = ComputeWindow (iWindType, iNumData, false);
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if (!pdWindow)
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{
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fprintf (stderr, "Memory error in Energy\n");
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return(0.0);
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}
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iWindLen = iNumData;
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}
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for (int i=0; i<iNumData; i++)
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{
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dWData = pdData[i] * pdWindow[i];
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dSum += dWData * dWData;
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}
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return (double)sqrt((double)(dSum/iNumData));
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}
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/*****************************************************************************
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* RemoveDc *
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*----------*
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* Description:
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*
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******************************************************************* PACOG ***/
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int RemoveDc (double* pdSamples, int iNumSamples)
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{
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double dDc = 0.0;
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assert (pdSamples);
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assert (iNumSamples>0);
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for (int i=0; i<iNumSamples; i++)
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{
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dDc += pdSamples[i];
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}
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dDc /= iNumSamples;
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for (i=0; i<iNumSamples; i++)
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{
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pdSamples[i] -= dDc;
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}
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return (int) dDc;
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}
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