1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
#include <fstream>
#include "allegro.h"
#include "audioreader.h"
#include "gen_chroma.h"
#include "comp_chroma.h"
using namespace std;
/* NORM_CHROMA
*
* This function normalizes the chroma for each frame of the
* chrom_energy to mean 0 and std. dev. 1. But if this is a
* "silent frame", set the 13th element to 1.
*/
void norm_chroma( int len, float *chrom_energy ) {
float avg = 0;
float dev = 0;
float sum = 0;
for( int i = 0; i < len; i++ ) {
/* Calculate avg for this frame */
sum = 0;
for ( int j = 0; j < 12; j++ )
sum += AREF2(chrom_energy, i, j);
avg = sum / 12.0;
/* Silence detection: */
float silence = 0.0F;
if (avg < SILENCE_THRESHOLD) { /* assume silent */
silence = 1.0F;
}
AREF2(chrom_energy, i, 12) = silence;
// printf("avg at %g: %g\n", i * 0.25, avg);
/* Normalize this frame to avg. 0 */
for ( int j = 0; j < 12; j++ )
AREF2(chrom_energy, i, j) -= avg;
/* Calculate std. dev. for this frame */
sum = 0;
for ( int j = 0; j < 12; j++ ) {
float x = AREF2(chrom_energy, i, j);
sum += x * x;
}
dev = sqrt( sum / 12.0 );
if (dev == 0.0) dev = 1.0F; /* don't divide by zero */
/* Normalize this frame to std. dev. 1*/
for ( int j = 0; j < 12; j++ )
AREF2(chrom_energy, i, j) /= dev;
}
}
/* Returns the minimum of two values */
double min2( double x, double y ) {
return (x < y ? x : y);
}
/* GEN_DIST
*
* This function generates the Euclidean distance for points i
* and j in two chroma vectors for use with dynamic time warping of
* the chroma vectors.
*/
float gen_dist( int i, int j, float *chrom_energy1,
float *chrom_energy2 ) {
float sum = 0;
float MAX = 12.0;
if (AREF2(chrom_energy1, i, CHROMA_BIN_COUNT) !=
AREF2(chrom_energy2, j, CHROMA_BIN_COUNT)) {
//printf("gd%g ", SILENCE_DISTANCE); // print result
return SILENCE_DISTANCE;
}
/* Determine the distance between these vectors
chroma1[i] and chroma2[j] to return */
for (int k = 0; k < 12; k++) {
float x = AREF2(chrom_energy1, i, k);
float y = AREF2(chrom_energy2, j, k);
float diff = x - y;
sum += diff*diff ;
}
sum = min2( sqrt( sum ), MAX );
//printf("gd%g ", sum); // print the result
return sum;
}
|
