src/lib/doslib/ext/faad/aacaudio.c

   1 /* Castus/ISP AAC audio ADTS frame synchronization and detection */
   2 /* (C) 2010-2012 Jonathan Campbell */
   3
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <stdio.h>
   9
  10 #include "aacaudio.h"
  11
  12 static const unsigned int mpeg_aac_adts_audio_sample_rates[16] = {
  13     96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
  14     16000, 12000, 11025, 8000,  7350,  0,     0,     0
  15 };
  16
  17 static const unsigned char mpeg_aac_adts_audio_channels[8] = {
  18     0, 1, 2, 3, 4, 5, 6, 8
  19 };
  20
  21 void mpeg_aac_adts_audio_get_sync_info(mpeg_aac_adts_audio_sync_raw_pattern sp,mpeg_aac_adts_audio_sync_info *i) {
  22         i->id =                         (unsigned  char)((sp >> (56ULL-(12ULL+ 1ULL))) & 0x0001);
  23         i->layer =                      (unsigned  char)((sp >> (56ULL-(13ULL+ 2ULL))) & 0x0003);
  24         i->protection =                 (unsigned  char)((sp >> (56ULL-(15ULL+ 1ULL))) & 0x0001);
  25         i->object_type =                (unsigned  char)((sp >> (56ULL-(16ULL+ 2ULL))) & 0x0003);
  26         i->sample_rate_index =          (unsigned  char)((sp >> (56ULL-(18ULL+ 4ULL))) & 0x000F);
  27         i->private_bit =                (unsigned  char)((sp >> (56ULL-(22ULL+ 1ULL))) & 0x0001);
  28         i->channel_configuration =      (unsigned  char)((sp >> (56ULL-(23ULL+ 3ULL))) & 0x0007);
  29         i->original_copy =              (unsigned  char)((sp >> (56ULL-(26ULL+ 1ULL))) & 0x0001);
  30         i->home =                       (unsigned  char)((sp >> (56ULL-(27ULL+ 1ULL))) & 0x0001);
  31         i->copyright_id =               (unsigned  char)((sp >> (56ULL-(28ULL+ 1ULL))) & 0x0001);
  32         i->copyright_start =            (unsigned  char)((sp >> (56ULL-(29ULL+ 1ULL))) & 0x0001);
  33         i->aac_frame_length =           (unsigned short)((sp >> (56ULL-(30ULL+13ULL))) & 0x1FFF);
  34         i->buffer_fullness =            (unsigned short)((sp >> (56ULL-(43ULL+11ULL))) & 0x07FF);
  35         i->add_raw_data_blocks =        (unsigned  char)((sp >> (56ULL-(54ULL+ 2ULL))) & 0x0003);
  36         i->samples_per_frame =          1024;   /* FIXME: Digital Radio Mondale has 960 samples/frame? Do we need to support it? */
  37
  38         i->sample_rate = mpeg_aac_adts_audio_sample_rates[i->sample_rate_index];
  39         i->channels = mpeg_aac_adts_audio_channels[i->channel_configuration];
  40         i->total_raw_data_blocks = i->add_raw_data_blocks+1;
  41         i->total_samples = i->samples_per_frame * i->total_raw_data_blocks;
  42         i->sync = sp;
  43 }
  44
  45
  46 uint8_t *mpeg_aac_adts_audio_sync(uint8_t *ptr,uint8_t *fence,mpeg_aac_adts_audio_sync_raw_pattern *p,mpeg_aac_adts_audio_sync_info *i) {
  47         mpeg_aac_adts_audio_sync_raw_pattern sp = 0;
  48
  49         if ((ptr+7) > fence)
  50                 return ptr;
  51
  52         memset(i,0,sizeof(*i));
  53         while ((ptr+7) <= fence) {
  54                 sp <<= 8ULL;
  55                 sp  |= (mpeg_aac_adts_audio_sync_raw_pattern)(*ptr++);
  56
  57                 if (sp == (mpeg_aac_adts_audio_sync_raw_pattern)0xFFFFFFFFFFFFFFFFULL) {
  58                         ptr += 6-1;
  59                         continue;
  60                 }
  61                 if ((sp&0x00FFFF0000000000ULL) == 0x00FFFF0000000000ULL) {
  62                         continue;
  63                 }
  64                 if ((sp&0x00FFF00000000000ULL) != 0x00FFF00000000000ULL) /* 12-bit sync pattern */
  65                         continue;
  66                 if (p) *p = sp;
  67
  68                 mpeg_aac_adts_audio_get_sync_info(sp,i);
  69
  70                 /* NTS: aac_frame_length includes the ADTS header */
  71                 if (i->aac_frame_length < 7)
  72                         continue;
  73
  74                 i->sample_rate = mpeg_aac_adts_audio_sample_rates[i->sample_rate_index];
  75                 if (i->sample_rate == 0)
  76                         continue;
  77
  78                 i->channels = mpeg_aac_adts_audio_channels[i->channel_configuration];
  79                 if (i->channels == 0)
  80                         continue;
  81
  82                 i->total_raw_data_blocks = i->add_raw_data_blocks+1;
  83                 i->total_samples = i->samples_per_frame * i->total_raw_data_blocks;
  84                 i->sync = sp;
  85                 return ptr-7;
  86         }
  87
  88         return fence-7;
  89 }
  90
  91 int mpeg_aac_adts_audio_sync_same_format(mpeg_aac_adts_audio_sync_info *a,mpeg_aac_adts_audio_sync_info *b) {
  92         return (a->id                           == b->id &&
  93                 a->layer                        == b->layer &&
  94                 a->object_type                  == b->object_type &&
  95                 a->sample_rate_index            == b->sample_rate_index &&
  96                 a->channel_configuration        == b->channel_configuration);
  97 }
  98
  99