115 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			115 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * This file is part of FFmpeg.
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|  *
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|  * FFmpeg is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2.1 of the License, or (at your option) any later version.
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|  *
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|  * FFmpeg is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with FFmpeg; if not, write to the Free Software
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|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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|  */
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| 
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| #include <stdio.h>
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| #include <stdlib.h>
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| #include <string.h>
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| #include <math.h>
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| #include <inttypes.h>
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| 
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| #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
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| #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
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| 
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| static int64_t fsize(FILE *f) {
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|     int64_t end, pos = ftell(f);
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|     fseek(f, 0, SEEK_END);
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|     end = ftell(f);
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|     fseek(f, pos, SEEK_SET);
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|     return end;
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| }
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| 
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| int main(int argc, char **argv) {
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|     FILE *f[2];
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|     int i, pos;
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|     int siglen, datlen;
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|     int bestpos = 0;
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|     double bestc = 0;
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|     double sigamp = 0;
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|     int16_t *signal, *data;
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|     int maxshift = 16384;
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| 
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|     if (argc < 3) {
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|         printf("audiomatch <testfile> <reffile>\n");
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|         printf("WAV headers are skipped automatically.\n");
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|         return 1;
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|     }
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| 
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|     f[0] = fopen(argv[1], "rb");
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|     f[1] = fopen(argv[2], "rb");
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|     if (!f[0] || !f[1]) {
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|         fprintf(stderr, "Could not open input files.\n");
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|         return 1;
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|     }
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| 
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|     for (i = 0; i < 2; i++) {
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|         uint8_t p[100];
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|         if (fread(p, 1, 12, f[i]) != 12)
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|             return 1;
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|         if (!memcmp(p, "RIFF", 4) &&
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|             !memcmp(p + 8, "WAVE", 4)) {
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|             if (fread(p, 1, 8, f[i]) != 8)
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|                 return 1;
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|             while (memcmp(p, "data", 4)) {
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|                 int s = p[4] | p[5] << 8 | p[6] << 16 | p[7] << 24;
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|                 fseek(f[i], s, SEEK_CUR);
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|                 if (fread(p, 1, 8, f[i]) != 8)
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|                     return 1;
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|             }
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|         } else {
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|             fseek(f[i], -12, SEEK_CUR);
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|         }
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|     }
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| 
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|     datlen = fsize(f[0]) - ftell(f[0]);
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|     siglen = fsize(f[1]) - ftell(f[1]);
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|     data   = malloc(datlen * sizeof(*data));
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|     signal = malloc(siglen * sizeof(*signal));
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| 
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|     if (fread(data  , 1, datlen, f[0]) != datlen)
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|         return 1;
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|     if (fread(signal, 1, siglen, f[1]) != siglen)
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|         return 1;
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|     datlen /= 2;
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|     siglen /= 2;
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| 
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|     for (i = 0; i < siglen; i++) {
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|         signal[i] = ((uint8_t*)(signal + i))[0] + 256*((uint8_t*)(signal + i))[1];
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|         sigamp += signal[i] * signal[i];
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|     }
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|     for (i = 0; i < datlen; i++)
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|         data[i] = ((uint8_t*)(data + i))[0] + 256*((uint8_t*)(data + i))[1];
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| 
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|     for (pos = 0; pos < maxshift; pos = pos < 0 ? -pos: -pos-1) {
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|         int64_t c = 0;
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|         int testlen = FFMIN(siglen, datlen-pos);
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|         for (i = FFMAX(0, -pos); i < testlen; i++) {
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|             int j = pos + i;
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|             c += signal[i] * data[j];
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|         }
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|         if (fabs(c) > sigamp * 0.94)
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|             maxshift = FFMIN(maxshift, fabs(pos)+32);
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|         if (fabs(c) > fabs(bestc)) {
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|             bestc = c;
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|             bestpos = pos;
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|         }
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|     }
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|     printf("presig: %d postsig:%d c:%7.4f lenerr:%d\n", bestpos, datlen - siglen - bestpos, bestc / sigamp, datlen - siglen);
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| 
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|     return 0;
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| }
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