116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
#include "ADTSHeader.h"
|
|
#include "foundation/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;
|
|
}
|
|
|
|
size_t nsaac_adts_get_frame_bitrate(nsaac_adts_header_t header)
|
|
{
|
|
uint64_t bitrate = nsaac_adts_get_samplerate(header) * header->frame_length * 8 / 1024;
|
|
return (size_t)bitrate;
|
|
} |