tests/audiomatch.c

   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 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
  28
  29 static int64_t fsize(FILE *f) {
  30     int64_t end, pos = ftell(f);
  31     fseek(f, 0, SEEK_END);
  32     end = ftell(f);
  33     fseek(f, pos, SEEK_SET);
  34     return end;
  35 }
  36
  37 int main(int argc, char **argv) {
  38     FILE *f[2];
  39     int i, pos;
  40     int siglen, datlen;
  41     int bestpos = 0;
  42     double bestc = 0;
  43     double sigamp = 0;
  44     int16_t *signal, *data;
  45     int maxshift = 16384;
  46
  47     if (argc < 3) {
  48         printf("audiomatch <testfile> <reffile>\n");
  49         printf("WAV headers are skipped automatically.\n");
  50         return 1;
  51     }
  52
  53     f[0] = fopen(argv[1], "rb");
  54     f[1] = fopen(argv[2], "rb");
  55     if (!f[0] || !f[1]) {
  56         fprintf(stderr, "Could not open input files.\n");
  57         return 1;
  58     }
  59
  60     for (i = 0; i < 2; i++) {
  61         uint8_t p[100];
  62         if (fread(p, 1, 12, f[i]) != 12)
  63             return 1;
  64         if (!memcmp(p, "RIFF", 4) &&
  65             !memcmp(p + 8, "WAVE", 4)) {
  66             if (fread(p, 1, 8, f[i]) != 8)
  67                 return 1;
  68             while (memcmp(p, "data", 4)) {
  69                 int s = p[4] | p[5] << 8 | p[6] << 16 | p[7] << 24;
  70                 fseek(f[i], s, SEEK_CUR);
  71                 if (fread(p, 1, 8, f[i]) != 8)
  72                     return 1;
  73             }
  74         } else {
  75             fseek(f[i], -12, SEEK_CUR);
  76         }
  77     }
  78
  79     datlen = fsize(f[0]) - ftell(f[0]);
  80     siglen = fsize(f[1]) - ftell(f[1]);
  81     data   = malloc(datlen * sizeof(*data));
  82     signal = malloc(siglen * sizeof(*signal));
  83
  84     if (fread(data  , 1, datlen, f[0]) != datlen)
  85         goto read_fail;
  86     if (fread(signal, 1, siglen, f[1]) != siglen)
  87         goto read_fail;
  88     datlen /= 2;
  89     siglen /= 2;
  90
  91     for (i = 0; i < siglen; i++) {
  92         signal[i] = ((uint8_t*)(signal + i))[0] + 256*((uint8_t*)(signal + i))[1];
  93         sigamp += signal[i] * signal[i];
  94     }
  95     for (i = 0; i < datlen; i++)
  96         data[i] = ((uint8_t*)(data + i))[0] + 256*((uint8_t*)(data + i))[1];
  97
  98     for (pos = 0; pos < maxshift; pos = pos < 0 ? -pos: -pos-1) {
  99         int64_t c = 0;
 100         int testlen = FFMIN(siglen, datlen-pos);
 101         for (i = FFMAX(0, -pos); i < testlen; i++) {
 102             int j = pos + i;
 103             c += signal[i] * data[j];
 104         }
 105         if (FFABS(c) > sigamp * 0.94)
 106             maxshift = FFMIN(maxshift, FFABS(pos)+32);
 107         if (FFABS(c) > FFABS(bestc)) {
 108             bestc = c;
 109             bestpos = pos;
 110         }
 111     }
 112     printf("presig: %d postsig:%d c:%7.4f lenerr:%d\n", bestpos, datlen - siglen - bestpos, bestc / sigamp, datlen - siglen);
 113
 114     free(data);
 115     free(signal);
 116     return 0;
 117
 118 read_fail:
 119     free(data);
 120     free(signal);
 121     return 1;
 122 }