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/*
* 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))
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;
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));
fread(data , 1, datlen, f[0]);
fread(signal, 1, siglen, f[1]);
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(fabs(c) > sigamp * 0.94)
maxshift = FFMIN(maxshift, fabs(pos)+128);
if(fabs(c)>fabs(bestc)){
bestc= c;
bestpos = pos;
}
}
printf("presig: %d postsig:%d c:%7.4f\n", bestpos, datlen - siglen - bestpos, bestc / sigamp);
}
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