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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <inttypes.h>
#define FFMIN(a,b) ((a) > (b) ? (b) : (a))
#define FFMAX(a,b) ((a) > (b) ? (a) : (b))
#define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
static int64_t fsize(FILE *f) {
int64_t end, pos = ftell(f);
fseek(f, 0, SEEK_END);
end = ftell(f);
fseek(f, pos, SEEK_SET);
return end;
}
int main(int argc, char **argv) {
FILE *f[2];
int i, pos;
int siglen, datlen;
int bestpos = 0;
double bestc = 0;
double sigamp = 0;
int16_t *signal, *data;
int maxshift = 16384;
if (argc < 3) {
printf("audiomatch <testfile> <reffile>\n");
printf("WAV headers are skipped automatically.\n");
return 1;
}
f[0] = fopen(argv[1], "rb");
f[1] = fopen(argv[2], "rb");
if (!f[0] || !f[1]) {
fprintf(stderr, "Could not open input files.\n");
return 1;
}
for (i = 0; i < 2; i++) {
uint8_t p[100];
if (fread(p, 1, 12, f[i]) != 12)
return 1;
if (!memcmp(p, "RIFF", 4) &&
!memcmp(p + 8, "WAVE", 4)) {
if (fread(p, 1, 8, f[i]) != 8)
return 1;
while (memcmp(p, "data", 4)) {
int s = p[4] | p[5] << 8 | p[6] << 16 | p[7] << 24;
fseek(f[i], s, SEEK_CUR);
if (fread(p, 1, 8, f[i]) != 8)
return 1;
}
} else {
fseek(f[i], -12, SEEK_CUR);
}
}
datlen = fsize(f[0]) - ftell(f[0]);
siglen = fsize(f[1]) - ftell(f[1]);
data = malloc(datlen * sizeof(*data));
signal = malloc(siglen * sizeof(*signal));
if (fread(data , 1, datlen, f[0]) != datlen)
goto read_fail;
if (fread(signal, 1, siglen, f[1]) != siglen)
goto read_fail;
datlen /= 2;
siglen /= 2;
for (i = 0; i < siglen; i++) {
signal[i] = ((uint8_t*)(signal + i))[0] + 256*((uint8_t*)(signal + i))[1];
sigamp += signal[i] * signal[i];
}
for (i = 0; i < datlen; i++)
data[i] = ((uint8_t*)(data + i))[0] + 256*((uint8_t*)(data + i))[1];
for (pos = 0; pos < maxshift; pos = pos < 0 ? -pos: -pos-1) {
int64_t c = 0;
int testlen = FFMIN(siglen, datlen-pos);
for (i = FFMAX(0, -pos); i < testlen; i++) {
int j = pos + i;
c += signal[i] * data[j];
}
if (FFABS(c) > sigamp * 0.94)
maxshift = FFMIN(maxshift, FFABS(pos)+32);
if (FFABS(c) > FFABS(bestc)) {
bestc = c;
bestpos = pos;
}
}
printf("presig: %d postsig:%d c:%7.4f lenerr:%d\n", bestpos, datlen - siglen - bestpos, bestc / sigamp, datlen - siglen);
free(data);
free(signal);
return 0;
read_fail:
free(data);
free(signal);
return 1;
}
|
