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ffmpeg-4.2.2/tests/audiomatch.c 3.38 KB
aac5773f   hucm   功能基本完成,接口待打磨
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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 = 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)
          return 1;
      if (fread(signal, 1, siglen, f[1]) != siglen)
          return 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)+32);
          if (fabs(c) > fabs(bestc)) {
              bestc = c;
              bestpos = pos;
          }
      }
      printf("presig: %d postsig:%d c:%7.4f lenerr:%d\n", bestpos, datlen - siglen - bestpos, bestc / sigamp, datlen - siglen);
  
      return 0;
  }