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/* libxtract feature extraction library
*
* Copyright (C) 2006 Jamie Bullock
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
#include "xtract/libxtract.h"
#include <stdio.h>
#include <stdlib.h>
#define BLOCKSIZE 1024
#define SAMPLERATE 44100
#define PERIOD 100
#define MFCC_FREQ_BANDS 13
#define MFCC_FREQ_MIN 20
#define MFCC_FREQ_MAX 20000
int main(void)
{
float mean = 0.f;
float input[BLOCKSIZE];
float spectrum[BLOCKSIZE];
float mfccs[MFCC_FREQ_BANDS * sizeof(float)];
float argf[4];
int n;
xtract_mel_filter mel_filters;
/* fill the input array with a sawtooth wave */
for(n = 0; n < BLOCKSIZE; ++n)
{
input[n] = ((n % PERIOD) / (float)PERIOD) - .5;
}
/* get the mean of the input */
xtract[XTRACT_MEAN]((void *)&input, BLOCKSIZE, NULL, (void *)&mean);
printf("\nInput mean = %.2f\n\n", mean);
/* get the spectrum */
argf[0] = SAMPLERATE / (float)BLOCKSIZE;
argf[1] = XTRACT_MAGNITUDE_SPECTRUM;
argf[2] = 0.f;
argf[3] = 0.f;
xtract_init_fft(BLOCKSIZE, XTRACT_SPECTRUM);
xtract[XTRACT_SPECTRUM]((void *)&input, BLOCKSIZE, &argf[0], (void *)&spectrum[0]);
/* print the spectral bins */
printf("\nSpectral bins:\n");
for(n = 0; n < (BLOCKSIZE >> 1); ++n){
printf("freq: %.1f\tamp: %.6f\n", spectrum[n + (BLOCKSIZE >> 1)], spectrum[n]);
}
printf("\n");
/* compute the MFCCs */
mel_filters.n_filters = MFCC_FREQ_BANDS;
mel_filters.filters = malloc(MFCC_FREQ_BANDS * sizeof(float *));
for(n = 0; n < MFCC_FREQ_BANDS; ++n)
{
mel_filters.filters[n] = malloc(BLOCKSIZE * sizeof(float));
}
xtract_init_mfcc(BLOCKSIZE >> 1, SAMPLERATE >> 1, XTRACT_EQUAL_GAIN, MFCC_FREQ_MIN, MFCC_FREQ_MAX, mel_filters.n_filters, mel_filters.filters);
xtract_mfcc(spectrum, BLOCKSIZE >> 1, &mel_filters, mfccs);
/* print the MFCCs */
printf("MFCCs:\n");
for(n = 0; n < MFCC_FREQ_BANDS; ++n)
{
printf("band: %d\t", n);
if(n < 10) {
printf("\t");
}
printf("coeff: %f\n", mfccs[n]);
}
/* cleanup */
for(n = 0; n < MFCC_FREQ_BANDS; ++n)
{
free(mel_filters.filters[n]);
}
free(mel_filters.filters);
return 0;
}
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