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                 decoder_length = aac_read_decoder_length(p, &description_len);
  61                 PARA_INFO_LOG("decoder length: %d\n", decoder_length);
  62                 i += description_len;
  63                 *skip = i;
  64                 return decoder_length;
  65         }
  66         return -E_ESDS;
  67 }
  68
  69 unsigned aac_read_int32(unsigned char *buf)
  70 {
  71         uint8_t *d = (uint8_t*)buf;
  72         return (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | d[3];
  73 }
  74
  75
  76 int find_stco(unsigned char *buf, unsigned buflen, int *skip)
  77 {
  78         int i, ret;
  79
  80         for (i = 0; i + 16 < buflen; i++) {
  81                 unsigned char *p = buf + i;
  82
  83                 if (p[0] != 's' || p[1] != 't' || p[2] != 'c' || p[3] != 'o')
  84                         continue;
  85                 PARA_INFO_LOG("found stco@%d\n", i);
  86                 i += 8;
  87                 ret = aac_read_int32(buf + i);
  88                 i += 4;
  89                 PARA_INFO_LOG("num entries: %d\n", ret);
  90                 *skip = i;
  91                 return ret;
  92         }
  93         return -E_STCO;
  94 }
  95