FFmpeg  4.0
audiomatch.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <math.h>
23 #include <inttypes.h>
24 
25 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
26 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
27 
28 static int64_t fsize(FILE *f) {
29  int64_t end, pos = ftell(f);
30  fseek(f, 0, SEEK_END);
31  end = ftell(f);
32  fseek(f, pos, SEEK_SET);
33  return end;
34 }
35 
36 int main(int argc, char **argv) {
37  FILE *f[2];
38  int i, pos;
39  int siglen, datlen;
40  int bestpos = 0;
41  double bestc = 0;
42  double sigamp = 0;
43  int16_t *signal, *data;
44  int maxshift = 16384;
45 
46  if (argc < 3) {
47  printf("audiomatch <testfile> <reffile>\n");
48  printf("WAV headers are skipped automatically.\n");
49  return 1;
50  }
51 
52  f[0] = fopen(argv[1], "rb");
53  f[1] = fopen(argv[2], "rb");
54  if (!f[0] || !f[1]) {
55  fprintf(stderr, "Could not open input files.\n");
56  return 1;
57  }
58 
59  for (i = 0; i < 2; i++) {
60  uint8_t p[100];
61  if (fread(p, 1, 12, f[i]) != 12)
62  return 1;
63  if (!memcmp(p, "RIFF", 4) &&
64  !memcmp(p + 8, "WAVE", 4)) {
65  if (fread(p, 1, 8, f[i]) != 8)
66  return 1;
67  while (memcmp(p, "data", 4)) {
68  int s = p[4] | p[5] << 8 | p[6] << 16 | p[7] << 24;
69  fseek(f[i], s, SEEK_CUR);
70  if (fread(p, 1, 8, f[i]) != 8)
71  return 1;
72  }
73  } else {
74  fseek(f[i], -12, SEEK_CUR);
75  }
76  }
77 
78  datlen = fsize(f[0]) - ftell(f[0]);
79  siglen = fsize(f[1]) - ftell(f[1]);
80  data = malloc(datlen * sizeof(*data));
81  signal = malloc(siglen * sizeof(*signal));
82 
83  if (fread(data , 1, datlen, f[0]) != datlen)
84  return 1;
85  if (fread(signal, 1, siglen, f[1]) != siglen)
86  return 1;
87  datlen /= 2;
88  siglen /= 2;
89 
90  for (i = 0; i < siglen; i++) {
91  signal[i] = ((uint8_t*)(signal + i))[0] + 256*((uint8_t*)(signal + i))[1];
92  sigamp += signal[i] * signal[i];
93  }
94  for (i = 0; i < datlen; i++)
95  data[i] = ((uint8_t*)(data + i))[0] + 256*((uint8_t*)(data + i))[1];
96 
97  for (pos = 0; pos < maxshift; pos = pos < 0 ? -pos: -pos-1) {
98  int64_t c = 0;
99  int testlen = FFMIN(siglen, datlen-pos);
100  for (i = FFMAX(0, -pos); i < testlen; i++) {
101  int j = pos + i;
102  c += signal[i] * data[j];
103  }
104  if (fabs(c) > sigamp * 0.94)
105  maxshift = FFMIN(maxshift, fabs(pos)+32);
106  if (fabs(c) > fabs(bestc)) {
107  bestc = c;
108  bestpos = pos;
109  }
110  }
111  printf("presig: %d postsig:%d c:%7.4f lenerr:%d\n", bestpos, datlen - siglen - bestpos, bestc / sigamp, datlen - siglen);
112 
113  return 0;
114 }
const char * s
Definition: avisynth_c.h:768
int main(int argc, char **argv)
Definition: audiomatch.c:36
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
const char data[16]
Definition: mxf.c:90
#define FFMIN(a, b)
Definition: audiomatch.c:25
#define FFMAX(a, b)
Definition: audiomatch.c:26
static double c[64]
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28