aac_common.c

   1 #include "para.h"
   2 #include "aac.h"
   3 #include "error.h"
   4
   5 NeAACDecHandle aac_open(void)
   6 {
   7         NeAACDecHandle h = NeAACDecOpen();
   8         NeAACDecConfigurationPtr c = NeAACDecGetCurrentConfiguration(h);
   9
  10         c->defObjectType = LC;
  11         c->outputFormat = FAAD_FMT_16BIT;
  12         c->downMatrix = 0;
  13         NeAACDecSetConfiguration(h, c);
  14         return h;
  15 };
  16
  17 static int aac_read_decoder_length(unsigned char *buf, int *description_len)
  18 {
  19         uint8_t b;
  20         uint8_t numBytes = 0;
  21         uint32_t length = 0;
  22
  23         do {
  24                 b = buf[numBytes];
  25                 numBytes++;
  26                 length = (length << 7) | (b & 0x7F);
  27         } while
  28                 ((b & 0x80) && numBytes < 4);
  29         *description_len = numBytes;
  30         return length;
  31 }
  32
  33 int aac_find_esds(unsigned char *buf, unsigned buflen, int *skip)
  34 {
  35         int i;
  36
  37         for (i = 0; i + 4 < buflen; i++) {
  38                 unsigned char *p = buf + i;
  39                 int decoder_length, description_len;
  40
  41                 if (p[0] != 'e' || p[1] != 's' || p[2] != 'd' || p[3] != 's')
  42                         continue;
  43                 i += 8;
  44                 p = buf + i;
  45                 PARA_INFO_LOG("found esds@%d, next: %x\n", i, *p);
  46                 if (*p == 3)
  47                         i += 8;
  48                 else
  49                         i += 6;
  50                 p = buf + i;
  51                 PARA_INFO_LOG("next: %x\n", *p);
  52                 if (*p != 4)
  53                         continue;
  54                 i += 18;
  55                 p = buf + i;
  56                 PARA_INFO_LOG("next: %x\n", *p);
  57                 if (*p != 5)
  58                         continue;
  59                 i++;
  60                 p = buf + i;
  61                 decoder_length = aac_read_decoder_length(p, &description_len);
  62                 PARA_INFO_LOG("decoder length: %d\n", decoder_length);
  63                 i += description_len;
  64                 *skip = i;
  65                 return decoder_length;
  66         }
  67         return -E_ESDS;
  68 }
  69
  70 unsigned aac_read_int32(unsigned char *buf)
  71 {
  72         uint8_t *d = (uint8_t*)buf;
  73         return (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | d[3];
  74 }
  75
  76
  77 int aac_find_stco(unsigned char *buf, unsigned buflen, int *skip)
  78 {
  79         int i, ret;
  80
  81         for (i = 0; i + 16 < buflen; i++) {
  82                 unsigned char *p = buf + i;
  83
  84                 if (p[0] != 's' || p[1] != 't' || p[2] != 'c' || p[3] != 'o')
  85                         continue;
  86                 PARA_INFO_LOG("found stco@%d\n", i);
  87                 i += 8;
  88                 ret = aac_read_int32(buf + i);
  89                 i += 4;
  90                 PARA_INFO_LOG("num entries: %d\n", ret);
  91                 *skip = i;
  92                 return ret;
  93         }
  94         PARA_WARNING_LOG("stco not found, buflen: %d\n", buflen);
  95         return -E_STCO;
  96 }
  97
  98 int aac_find_stsz(unsigned char *buf, unsigned buflen, unsigned *skip)
  99 {
 100         int i, ret;
 101
 102         for (i = 0; i + 16 < buflen; i++) {
 103                 unsigned char *p = buf + i;
 104                 unsigned sample_count, sample_size;
 105
 106                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
 107                         continue;
 108                 PARA_INFO_LOG("found stsz@%d\n", i);
 109                 i += 8;
 110                 sample_size = aac_read_int32(buf + i);
 111                 PARA_INFO_LOG("sample size: %d\n", sample_size);
 112                 i += 4;
 113                 sample_count = aac_read_int32(buf + i);
 114                 i += 4;
 115                 PARA_INFO_LOG("sample count: %d\n", sample_count);
 116                 *skip = i;
 117                 return sample_count;
 118         }
 119         PARA_WARNING_LOG("stsz not found, buflen: %d\n", buflen);
 120         return -E_STCO;
 121 }
 122