audacia/lib-src/libscorealign/comp_chroma.cpp

50 lines
1.2 KiB
C++

/* comp_chroma.cpp -- compute chroma distance
*
* 2008 RBD
*/
#include <string.h>
#include <math.h>
#include <fstream>
#include <algorithm>
#include "allegro.h"
#include "audioreader.h"
#include "scorealign.h"
#include "gen_chroma.h"
#include "comp_chroma.h"
using namespace std;
#ifdef min
#undef min
#endif
#define min(x,y) ((x)<(y)?(x):(y))
#define SILENCE_DISTANCE 16.0
/* 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 Scorealign::gen_dist(int i, int j)
{
const float MAX = 12.0;
assert(i < file0_frames);
assert(j < file1_frames);
float *cv0 = AREF1(chrom_energy0, i);
float *cv1 = AREF1(chrom_energy1, j);
if (cv0[CHROMA_BIN_COUNT] != cv1[CHROMA_BIN_COUNT]) {
// silent frames are a (large) constant distance from non-silent frames
return SILENCE_DISTANCE;
}
/* calculate the Euclidean distance between these vectors */
float sum = 0;
for (int k = 0; k < CHROMA_BIN_COUNT; k++) {
float diff = cv0[k] - cv1[k];
sum += diff * diff ;
}
// place a ceiling (MAX) on distance
return min(sqrt(sum), MAX);
}