jamie@1: /* libxtract feature extraction library
jamie@1:  *  
jamie@1:  * Copyright (C) 2006 Jamie Bullock
jamie@1:  *
jamie@1:  * This program is free software; you can redistribute it and/or modify
jamie@1:  * it under the terms of the GNU General Public License as published by
jamie@1:  * the Free Software Foundation; either version 2 of the License, or
jamie@1:  * (at your option) any later version.
jamie@1:  *
jamie@1:  * This program is distributed in the hope that it will be useful,
jamie@1:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
jamie@1:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
jamie@1:  * GNU General Public License for more details.
jamie@1:  *
jamie@1:  * You should have received a copy of the GNU General Public License
jamie@1:  * along with this program; if not, write to the Free Software
jamie@1:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
jamie@1:  * USA.
jamie@1:  */
jamie@1: 
jamie@1: /* init.c: defines functions that extract a feature as a single value from an input vector */
jamie@1: 
jamie@1: #include "xtract/libxtract.h"
jamie@1: #include <math.h>
jamie@26: #include <stdlib.h>
jamie@1: 
jamie@43: int xtract_init_mfcc(int N, float nyquist, int style, float freq_min, float freq_max, int freq_bands, float **fft_tables){
jamie@1: 
jamie@39:     int n, i, k, *fft_peak, M, next_peak; 
jamie@1:     float norm, mel_freq_max, mel_freq_min, norm_fact, height, inc, val, 
jamie@1:         freq_bw_mel, *mel_peak, *height_norm, *lin_peak;
jamie@1: 
jamie@1:     mel_peak = height_norm = lin_peak = NULL;
jamie@1:     fft_peak = NULL;
jamie@1:     norm = 1; 
jamie@1: 
jamie@1:     mel_freq_max = 1127 * log(1 + freq_max / 700);
jamie@1:     mel_freq_min = 1127 * log(1 + freq_min / 700);
jamie@1:     freq_bw_mel = (mel_freq_max - mel_freq_min) / freq_bands;
jamie@1: 
jamie@1:     mel_peak = (float *)malloc((freq_bands + 2) * sizeof(float)); 
jamie@1:     /* +2 for zeros at start and end */
jamie@1:     lin_peak = (float *)malloc((freq_bands + 2) * sizeof(float));
jamie@1:     fft_peak = (int *)malloc((freq_bands + 2) * sizeof(int));
jamie@1:     height_norm = (float *)malloc(freq_bands * sizeof(float));
jamie@1: 
jamie@1:     if(mel_peak == NULL || height_norm == NULL || 
jamie@1:                     lin_peak == NULL || fft_peak == NULL)
jamie@1:                     return MALLOC_FAILED;
jamie@39:     
jamie@1:     M = N >> 1;
jamie@1: 
jamie@1:     mel_peak[0] = mel_freq_min;
jamie@1:     lin_peak[0] = 700 * (exp(mel_peak[0] / 1127) - 1);
jamie@1:     fft_peak[0] = lin_peak[0] / nyquist * M;
jamie@1: 
jamie@1: 
jamie@1:     for (n = 1; n <= freq_bands; n++){	
jamie@1:     /*roll out peak locations - mel, linear and linear on fft window scale */
jamie@1:         mel_peak[n] = mel_peak[n - 1] + freq_bw_mel;
jamie@1:         lin_peak[n] = 700 * (exp(mel_peak[n] / 1127) -1);
jamie@1:         fft_peak[n] = lin_peak[n] / nyquist * M;
jamie@1:     }
jamie@1: 
jamie@1:     for (n = 0; n < freq_bands; n++){
jamie@1:         /*roll out normalised gain of each peak*/
jamie@1:         if (style == EQUAL_GAIN){
jamie@1:             height = 1;	
jamie@1:             norm_fact = norm;
jamie@1:         }
jamie@1:         else{
jamie@1:             height = 2 / (lin_peak[n + 2] - lin_peak[n]);
jamie@1:             norm_fact = norm / (2 / (lin_peak[2] - lin_peak[0]));
jamie@1:         }
jamie@1:         height_norm[n] = height * norm_fact;
jamie@1:     }
jamie@1: 
jamie@1:     i = 0;
jamie@1:    
jamie@1:     for(n = 0; n < freq_bands; n++){
jamie@39: 	
jamie@39: 	/*calculate the rise increment*/
jamie@1:         if(n > 0)
jamie@1:             inc = height_norm[n] / (fft_peak[n] - fft_peak[n - 1]);
jamie@1:         else
jamie@1:             inc = height_norm[n] / fft_peak[n];
jamie@1:         val = 0;	
jamie@39: 	
jamie@39: 	/*zero the start of the array*/
jamie@39: 	for(k = 0; k < i; k++)
jamie@39: 	   fft_tables[n][k] = 0.f;
jamie@39: 	
jamie@39: 	/*fill in the rise */
jamie@1:         for(; i <= fft_peak[n]; i++){ 
jamie@1:             fft_tables[n][i] = val;
jamie@1:             val += inc;
jamie@1:         }
jamie@39: 	
jamie@39:         /*calculate the fall increment */
jamie@1:         inc = height_norm[n] / (fft_peak[n + 1] - fft_peak[n]);
jamie@39: 	
jamie@1:         val = 0;
jamie@39: 	next_peak = fft_peak[n + 1];
jamie@39: 	
jamie@39: 	/*reverse fill the 'fall' */
jamie@39:         for(i = next_peak; i > fft_peak[n]; i--){ 
jamie@1:             fft_tables[n][i] = val;
jamie@1:             val += inc;
jamie@1:         }
jamie@39: 
jamie@39: 	/*zero the rest of the array*/
jamie@39: 	for(k = next_peak + 1; k < N; k++)
jamie@39: 	    fft_tables[n][k] = 0.f;
jamie@1:     }
jamie@1: 
jamie@1:     free(mel_peak);
jamie@1:     free(lin_peak);
jamie@1:     free(height_norm);
jamie@1:     free(fft_peak);
jamie@1: 
jamie@1:     return SUCCESS;
jamie@1: 
jamie@1: }
jamie@1: 
jamie@1: int xtract_init_bark(int N, float nyquist, int *band_limits){
jamie@1: 
jamie@38:     float  edges[] = {0, 100, 200, 300, 400, 510, 630, 770, 920, 1080, 1270, 1480, 1720, 2000, 2320, 2700, 3150, 3700, 4400, 5300, 6400, 7700, 9500, 12000, 15500, 20500, 27000}; /* Takes us up to sr = 54kHz (CCRMA: JOS)*/
jamie@1: 
jamie@1:     int M, bands = BARK_BANDS;
jamie@1:     
jamie@1:     M = N >> 1;
jamie@1:     
jamie@1:     while(bands--)
jamie@1:         band_limits[bands] = edges[bands] / nyquist * M;
jamie@1:         /*FIX shohuld use rounding, but couldn't get it to work */
jamie@38: 
jamie@38:     return SUCCESS;
jamie@1: }