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livetrax/libs/qm-dsp/dsp/mfcc/MFCC.cpp

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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
QM DSP Library
Centre for Digital Music, Queen Mary, University of London.
This file copyright 2005 Nicolas Chetry, copyright 2008 QMUL.
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. See the file
COPYING included with this distribution for more information.
*/
#include <cmath>
#include <cstdlib>
#include <cstring>
#include "MFCC.h"
#include "dsp/transforms/FFT.h"
#include "base/Window.h"
MFCC::MFCC(MFCCConfig config)
{
int i,j;
/* Calculate at startup */
double *freqs, *lower, *center, *upper, *triangleHeight, *fftFreqs;
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lowestFrequency = 66.6666666;
linearFilters = 13;
linearSpacing = 66.66666666;
logFilters = 27;
logSpacing = 1.0711703;
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/* FFT and analysis window sizes */
fftSize = config.fftsize;
fft = new FFTReal(fftSize);
totalFilters = linearFilters + logFilters;
logPower = config.logpower;
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samplingRate = config.FS;
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/* The number of cepstral componenents */
nceps = config.nceps;
/* Set if user want C0 */
WANT_C0 = (config.want_c0 ? 1 : 0);
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/* Allocate space for feature vector */
if (WANT_C0 == 1) {
ceps = (double*)calloc(nceps+1, sizeof(double));
} else {
ceps = (double*)calloc(nceps, sizeof(double));
}
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/* Allocate space for local vectors */
mfccDCTMatrix = (double**)calloc(nceps+1, sizeof(double*));
for (i = 0; i < nceps+1; i++) {
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mfccDCTMatrix[i]= (double*)calloc(totalFilters, sizeof(double));
}
mfccFilterWeights = (double**)calloc(totalFilters, sizeof(double*));
for (i = 0; i < totalFilters; i++) {
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mfccFilterWeights[i] = (double*)calloc(fftSize, sizeof(double));
}
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freqs = (double*)calloc(totalFilters+2,sizeof(double));
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lower = (double*)calloc(totalFilters,sizeof(double));
center = (double*)calloc(totalFilters,sizeof(double));
upper = (double*)calloc(totalFilters,sizeof(double));
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triangleHeight = (double*)calloc(totalFilters,sizeof(double));
fftFreqs = (double*)calloc(fftSize,sizeof(double));
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for (i = 0; i < linearFilters; i++) {
freqs[i] = lowestFrequency + ((double)i) * linearSpacing;
}
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for (i = linearFilters; i < totalFilters+2; i++) {
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freqs[i] = freqs[linearFilters-1] *
pow(logSpacing, (double)(i-linearFilters+1));
}
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/* Define lower, center and upper */
memcpy(lower, freqs,totalFilters*sizeof(double));
memcpy(center, &freqs[1],totalFilters*sizeof(double));
memcpy(upper, &freqs[2],totalFilters*sizeof(double));
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for (i=0;i<totalFilters;i++){
triangleHeight[i] = 2./(upper[i]-lower[i]);
}
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for (i=0;i<fftSize;i++){
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fftFreqs[i] = ((double) i / ((double) fftSize ) *
(double) samplingRate);
}
/* Build now the mccFilterWeight matrix */
for (i=0;i<totalFilters;i++){
for (j=0;j<fftSize;j++) {
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if ((fftFreqs[j] > lower[i]) && (fftFreqs[j] <= center[i])) {
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mfccFilterWeights[i][j] = triangleHeight[i] *
(fftFreqs[j]-lower[i]) / (center[i]-lower[i]);
}
else
{
mfccFilterWeights[i][j] = 0.0;
}
if ((fftFreqs[j]>center[i]) && (fftFreqs[j]<upper[i])) {
mfccFilterWeights[i][j] = mfccFilterWeights[i][j]
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+ triangleHeight[i] * (upper[i]-fftFreqs[j])
/ (upper[i]-center[i]);
}
else
{
mfccFilterWeights[i][j] = mfccFilterWeights[i][j] + 0.0;
}
}
}
/*
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* We calculate now mfccDCT matrix
* NB: +1 because of the DC component
*/
const double pi = 3.14159265358979323846264338327950288;
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for (i = 0; i < nceps+1; i++) {
for (j = 0; j < totalFilters; j++) {
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mfccDCTMatrix[i][j] = (1./sqrt((double) totalFilters / 2.))
* cos((double) i * ((double) j + 0.5) / (double) totalFilters * pi);
}
}
for (j = 0; j < totalFilters; j++){
mfccDCTMatrix[0][j] = (sqrt(2.)/2.) * mfccDCTMatrix[0][j];
}
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/* The analysis window */
window = new Window<double>(config.window, fftSize);
/* Allocate memory for the FFT */
realOut = (double*)calloc(fftSize, sizeof(double));
imagOut = (double*)calloc(fftSize, sizeof(double));
earMag = (double*)calloc(totalFilters, sizeof(double));
fftMag = (double*)calloc(fftSize/2, sizeof(double));
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free(freqs);
free(lower);
free(center);
free(upper);
free(triangleHeight);
free(fftFreqs);
}
MFCC::~MFCC()
{
int i;
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/* Free the structure */
for (i = 0; i < nceps+1; i++) {
free(mfccDCTMatrix[i]);
}
free(mfccDCTMatrix);
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for (i = 0; i < totalFilters; i++) {
free(mfccFilterWeights[i]);
}
free(mfccFilterWeights);
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/* Free the feature vector */
free(ceps);
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/* The analysis window */
delete window;
free(earMag);
free(fftMag);
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/* Free the FFT */
free(realOut);
free(imagOut);
delete fft;
}
/*
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*
* Extract the MFCC on the input frame
*
*/
int MFCC::process(const double *inframe, double *outceps)
{
double *inputData = (double *)malloc(fftSize * sizeof(double));
for (int i = 0; i < fftSize; ++i) inputData[i] = inframe[i];
window->cut(inputData);
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/* Calculate the fft on the input frame */
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fft->forward(inputData, realOut, imagOut);
free(inputData);
return process(realOut, imagOut, outceps);
}
int MFCC::process(const double *real, const double *imag, double *outceps)
{
int i, j;
for (i = 0; i < fftSize/2; ++i) {
fftMag[i] = sqrt(real[i] * real[i] + imag[i] * imag[i]);
}
for (i = 0; i < totalFilters; ++i) {
earMag[i] = 0.0;
}
/* Multiply by mfccFilterWeights */
for (i = 0; i < totalFilters; i++) {
double tmp = 0.0;
for (j = 0; j < fftSize/2; j++) {
tmp = tmp + (mfccFilterWeights[i][j] * fftMag[j]);
}
if (tmp > 0) earMag[i] = log10(tmp);
else earMag[i] = 0.0;
if (logPower != 1.0) {
earMag[i] = pow(earMag[i], logPower);
}
}
/*
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*
* Calculate now the cepstral coefficients
* with or without the DC component
*
*/
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if (WANT_C0 == 1) {
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for (i = 0; i < nceps+1; i++) {
double tmp = 0.;
for (j = 0; j < totalFilters; j++){
tmp = tmp + mfccDCTMatrix[i][j] * earMag[j];
}
outceps[i] = tmp;
}
}
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else
{
for (i = 1; i < nceps+1; i++) {
double tmp = 0.;
for (j = 0; j < totalFilters; j++){
tmp = tmp + mfccDCTMatrix[i][j] * earMag[j];
}
outceps[i-1] = tmp;
}
}
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return nceps;
}