Initial import

1 files changed, 124 insertions, 0 deletions

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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.
+ */
+
+/* init.c: defines functions that extract a feature as a single value from an input vector */
+
+#include "xtract/libxtract.h"
+#include <math.h>
+#include <string.h>
+
+int xtract_init_mfcc(int N, float nyquist, int style, float freq_max, float freq_min, int freq_bands, float **fft_tables){
+
+    int n,i, *fft_peak, M; 
+    float norm, mel_freq_max, mel_freq_min, norm_fact, height, inc, val, 
+        freq_bw_mel, *mel_peak, *height_norm, *lin_peak;
+
+
+    mel_peak = height_norm = lin_peak = NULL;
+    fft_peak = NULL;
+    norm = 1; 
+
+    mel_freq_max = 1127 * log(1 + freq_max / 700);
+    mel_freq_min = 1127 * log(1 + freq_min / 700);
+    freq_bw_mel = (mel_freq_max - mel_freq_min) / freq_bands;
+
+    mel_peak = (float *)malloc((freq_bands + 2) * sizeof(float)); 
+    /* +2 for zeros at start and end */
+    lin_peak = (float *)malloc((freq_bands + 2) * sizeof(float));
+    fft_peak = (int *)malloc((freq_bands + 2) * sizeof(int));
+    height_norm = (float *)malloc(freq_bands * sizeof(float));
+
+    if(mel_peak == NULL || height_norm == NULL || 
+                    lin_peak == NULL || fft_peak == NULL)
+                    return MALLOC_FAILED;
+        
+    M = N >> 1;
+
+    mel_peak[0] = mel_freq_min;
+    lin_peak[0] = 700 * (exp(mel_peak[0] / 1127) - 1);
+    fft_peak[0] = lin_peak[0] / nyquist * M;
+
+
+    for (n = 1; n <= freq_bands; n++){	
+    /*roll out peak locations - mel, linear and linear on fft window scale */
+        mel_peak[n] = mel_peak[n - 1] + freq_bw_mel;
+        lin_peak[n] = 700 * (exp(mel_peak[n] / 1127) -1);
+        fft_peak[n] = lin_peak[n] / nyquist * M;
+    }
+
+    for (n = 0; n < freq_bands; n++){
+        /*roll out normalised gain of each peak*/
+        if (style == EQUAL_GAIN){
+            height = 1;	
+            norm_fact = norm;
+        }
+        else{
+            height = 2 / (lin_peak[n + 2] - lin_peak[n]);
+            norm_fact = norm / (2 / (lin_peak[2] - lin_peak[0]));
+        }
+        height_norm[n] = height * norm_fact;
+    }
+
+    i = 0;
+   
+    for(n = 0; n < freq_bands; n++){
+        if(n > 0)
+            /*calculate the rise increment*/
+            inc = height_norm[n] / (fft_peak[n] - fft_peak[n - 1]);
+        else
+            inc = height_norm[n] / fft_peak[n];
+        val = 0;	
+        for(; i <= fft_peak[n]; i++){ 
+            /*fill in the 'rise' */
+            fft_tables[n][i] = val;
+            val += inc;
+        }
+        inc = height_norm[n] / (fft_peak[n + 1] - fft_peak[n]);
+        /*calculate the fall increment */
+        val = 0;
+        for(i = fft_peak[n + 1]; i > fft_peak[n]; i--){ 
+            /*reverse fill the 'fall' */
+            fft_tables[n][i] = val;
+            val += inc;
+        }
+    }
+
+    
+    free(mel_peak);
+    free(lin_peak);
+    free(height_norm);
+    free(fft_peak);
+
+    return SUCCESS;
+
+}
+
+int xtract_init_bark(int N, float nyquist, int *band_limits){
+
+    float  bark_freq_max, bark_freq_min, freq_bw_bark, temp, 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)*/
+
+    int M, bands = BARK_BANDS;
+    
+    M = N >> 1;
+    
+    while(bands--)
+        band_limits[bands] = edges[bands] / nyquist * M;
+        /*FIX shohuld use rounding, but couldn't get it to work */
+}