Re: Tech report fkiswav1.lzh

失礼，続きでーす．

/* check Microsoft RIFF-WAVE header
 * return data offset
 *        == 0 : Not wav file
 *        < 0  : Not supported format
 */
int check_wav_header(buf)
     unsigned char *buf;
{
  int i;
  long data_rate;
  long data_channel;
  unsigned char *p;
  long len;

  sound_little_endian = 1;
  if (strncmp(buf, "RIFF", 4))
    return 0;			/* Not wav file */
  len = get_long(buf+4);
  if (strncmp(buf+8, "WAVE", 4))
    return 0;			/* Not wav file */

  p = buf+12;
  while (strncmp(p, "fmt ", 4) != 0) {
    len = get_long(p+4);
    p += 8 + len;
  }
  len = get_long(p+4);
  
  p += 8;
  i = get_short(p);
  switch (i) {
  case 0x0001:			/* WAVE_FORMAT_PCM */
    break;
  case 0x0000:			/* WAVE_FORMAT_UNKNOWN */
  case 0x0002:			/* WAVE_FORMAT_ADPCM */
  case 0x0006:			/* WAVE_FORMAT_ALAW */
  case 0x0007:			/* WAVE_FORMAT_MULAW */
  case 0x0010:			/* WAVE_FORMAT_OKI_ADPCM */
  case 0x0015:			/* WAVE_FORMAT_DIGISTD */
  case 0x0016:			/* WAVE_FORMAT_DIGIFIX */
  case 0x0101:			/* IBM_FORMAT_MULAW */
  case 0x0102:			/* IBM_FORMAT_ALAW */
  case 0x0103:			/* IBM_FORMAT_ADPCM */
  default:
    if (sound_debug)
      fprintf(stderr, "RIFF-WAVE format 0x%04x not supported!\n", i);
    return -1;			/* Not supported format */
  }
  data_channel = get_short(p+2);
  data_rate = get_long(p+4);
  /* long: average bytes/second */
  /* short: block align */
  i = get_short(p+14);		/* bits/sample? */
  if (sound_debug)
    fprintf(stderr, "RIFF-WAVE %ld-channels, %ldHz, %d-bits/sample\n",
	    data_channel, data_rate, i);
  switch (i) {
  case 8:
    i = 1; sound_bits = 8; sound_unsigned = 1;
    break;
  case 16:
    i = 2; sound_bits = 16; sound_unsigned = 0;
    break;
  case 32:
    i = 4; sound_bits = 32; sound_unsigned = 0;
    break;
  default:
    if (sound_debug)
      fprintf(stderr, "RIFF-WAVE 0x%04x-bits/sample not supported!\n", i);
    return -1;			/* Not supported format */
  }
  p += len;
  
  if (strncmp(p, "data", 4)) {
    if (sound_debug)
      fprintf(stderr, "RIFF-WAVE data lost!\n");
    return -1;			/* Not supported format */
  }
  /* number of samples = get_long(p+4) / i */
  sound_channels = data_channel;
  sound_rate = data_rate;
  sound_ulaw_encoded = 0;
  p += 8;
  if (sound_debug)
    fprintf(stderr, "RIFF-WAVE offset %d\n", p - buf);
  return p - buf;		/* return data offset */
}

というわけで，なぜか "data" が
ないないたいです！？ うーむ？謎

それから，最後に ブツッ！とノイズが聞こえるのが多かったと
思うのですが？これもなぞです．

                                        UHD98984@pcvan.or.jp
                                                        yav