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#include "ADTSHeader.h"
#include <bfc/error.h>
enum
{
ADTS_NOT_PROTECTED=1,
ADTS_PROTECTED=0,
ADTS_SYNC = 0xFFF,
ADTS_MAIN = 0x00,
ADTS_LC = 0x01,
ADTS_SSR = 0x10,
ADTS_LTP = 0x11,
};
int nsaac_adts_parse(nsaac_adts_header_t header, const uint8_t *buffer)
{
unsigned int syncword = (buffer[0] << 4) | (buffer[1] >> 4);
unsigned int layer;
unsigned int sample_rate_index;
if (syncword != ADTS_SYNC)
return NErr_LostSynchronization;
header->syncword = syncword;
header->id = (buffer[1] >> 3) & 1;
layer = (buffer[1] >> 1) & 3;
if (layer != 0)
return NErr_WrongFormat;
header->layer = layer;
header->protection = (buffer[1]) & 1;
header->profile = (buffer[2] >> 6) & 3;
sample_rate_index = (buffer[2] >> 2) & 0xF;
if (sample_rate_index == 15)
return NErr_UnsupportedFormat; // might actually be OK if we can separately signal the sample rate
if (sample_rate_index > 13)
return NErr_Reserved;
header->sample_rate_index = sample_rate_index;
header->private_bit = (buffer[2] >> 1) & 1;
header->channel_configuration = ((buffer[2] & 1) << 2) | ((buffer[3] >> 6) & 3);
header->original = (buffer[3] >> 5) &1;
header->home = (buffer[3] >> 4) &1;
//copyright_identification_bit = (buffer[3] >> 3) & 1;
//copyright_identification_start = (buffer[3] >> 2) & 1;
header->frame_length = ((buffer[3] & 3) << 11) | (buffer[4]<<3) | ((buffer[5] >> 5) & 7);
header->buffer_fullness = ((buffer[5] & 0x1F) << 6) | (buffer[6] >> 2);
header->num_data_blocks = buffer[6] & 3;
return NErr_Success;
}
static const unsigned int aac_sratetab[] =
{
96000,
88200,
64000,
48000,
44100,
32000,
24000,
22050,
16000,
12000,
11025,
8000,
7350,
};
unsigned int nsaac_adts_get_samplerate(nsaac_adts_header_t header)
{
return aac_sratetab[header->sample_rate_index];
}
int nsaac_adts_match(nsaac_adts_header_t header1, nsaac_adts_header_t header2)
{
if (header1->id != header2->id)
return NErr_False;
if (header1->profile != header2->profile)
return NErr_False;
if (header1->sample_rate_index != header2->sample_rate_index)
return NErr_False;
if (header1->channel_configuration != header2->channel_configuration)
return NErr_False;
return NErr_True;
}
int nsaac_adts_get_channel_count(nsaac_adts_header_t header)
{
switch(header->channel_configuration)
{
case 7:
return 8;
default:
return header->channel_configuration;
}
}
size_t nsaac_adts_get_header_size(nsaac_adts_header_t header)
{
if (header->protection == ADTS_PROTECTED)
return 9;
else
return 7;
}
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