public function getAACADIFheaderFilepointer()
{
$info =& $this->getid3->info;
$info['fileformat'] = 'aac';
$info['audio']['dataformat'] = 'aac';
$info['audio']['lossless'] = false;
$this->fseek($info['avdataoffset']);
$AACheader = $this->fread(1024);
$offset = 0;
if (substr($AACheader, 0, 4) == 'ADIF') {
// http://faac.sourceforge.net/wiki/index.php?page=ADIF
// http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
// adif_header() {
// adif_id 32
// copyright_id_present 1
// if( copyright_id_present )
// copyright_id 72
// original_copy 1
// home 1
// bitstream_type 1
// bitrate 23
// num_program_config_elements 4
// for (i = 0; i < num_program_config_elements + 1; i++ ) {
// if( bitstream_type == '0' )
// adif_buffer_fullness 20
// program_config_element()
// }
// }
$AACheaderBitstream = Utils::BigEndian2Bin($AACheader);
$bitoffset = 0;
$info['aac']['header_type'] = 'ADIF';
$bitoffset += 32;
$info['aac']['header']['mpeg_version'] = 4;
$info['aac']['header']['copyright'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
$bitoffset += 1;
if ($info['aac']['header']['copyright']) {
$info['aac']['header']['copyright_id'] = Utils::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
$bitoffset += 72;
}
$info['aac']['header']['original_copy'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
$bitoffset += 1;
$info['aac']['header']['home'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
$bitoffset += 1;
$info['aac']['header']['is_vbr'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
$bitoffset += 1;
if ($info['aac']['header']['is_vbr']) {
$info['audio']['bitrate_mode'] = 'vbr';
$info['aac']['header']['bitrate_max'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
$bitoffset += 23;
} else {
$info['audio']['bitrate_mode'] = 'cbr';
$info['aac']['header']['bitrate'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
$bitoffset += 23;
$info['audio']['bitrate'] = $info['aac']['header']['bitrate'];
}
if ($info['audio']['bitrate'] == 0) {
$info['error'][] = 'Corrupt AAC file: bitrate_audio == zero';
return false;
}
$info['aac']['header']['num_program_configs'] = 1 + Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
for ($i = 0; $i < $info['aac']['header']['num_program_configs']; $i++) {
// http://www.audiocoding.com/wiki/index.php?page=program_config_element
// buffer_fullness 20
// element_instance_tag 4
// object_type 2
// sampling_frequency_index 4
// num_front_channel_elements 4
// num_side_channel_elements 4
// num_back_channel_elements 4
// num_lfe_channel_elements 2
// num_assoc_data_elements 3
// num_valid_cc_elements 4
// mono_mixdown_present 1
// mono_mixdown_element_number 4 if mono_mixdown_present == 1
// stereo_mixdown_present 1
// stereo_mixdown_element_number 4 if stereo_mixdown_present == 1
// matrix_mixdown_idx_present 1
// matrix_mixdown_idx 2 if matrix_mixdown_idx_present == 1
// pseudo_surround_enable 1 if matrix_mixdown_idx_present == 1
// for (i = 0; i < num_front_channel_elements; i++) {
// front_element_is_cpe[i] 1
// front_element_tag_select[i] 4
// }
// for (i = 0; i < num_side_channel_elements; i++) {
// side_element_is_cpe[i] 1
// side_element_tag_select[i] 4
// }
// for (i = 0; i < num_back_channel_elements; i++) {
// back_element_is_cpe[i] 1
// back_element_tag_select[i] 4
// }
// for (i = 0; i < num_lfe_channel_elements; i++) {
// lfe_element_tag_select[i] 4
// }
// for (i = 0; i < num_assoc_data_elements; i++) {
// assoc_data_element_tag_select[i] 4
// }
// for (i = 0; i < num_valid_cc_elements; i++) {
// cc_element_is_ind_sw[i] 1
// valid_cc_element_tag_select[i] 4
// }
// byte_alignment() VAR
// comment_field_bytes 8
// for (i = 0; i < comment_field_bytes; i++) {
// comment_field_data[i] 8
// }
if (!$info['aac']['header']['is_vbr']) {
$info['aac']['program_configs'][$i]['buffer_fullness'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
$bitoffset += 20;
}
$info['aac']['program_configs'][$i]['element_instance_tag'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
$info['aac']['program_configs'][$i]['object_type'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
$bitoffset += 2;
$info['aac']['program_configs'][$i]['sampling_frequency_index'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
$info['aac']['program_configs'][$i]['num_front_channel_elements'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
$info['aac']['program_configs'][$i]['num_side_channel_elements'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
$info['aac']['program_configs'][$i]['num_back_channel_elements'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
$info['aac']['program_configs'][$i]['num_lfe_channel_elements'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
$bitoffset += 2;
$info['aac']['program_configs'][$i]['num_assoc_data_elements'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
$bitoffset += 3;
$info['aac']['program_configs'][$i]['num_valid_cc_elements'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
$info['aac']['program_configs'][$i]['mono_mixdown_present'] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
if ($info['aac']['program_configs'][$i]['mono_mixdown_present']) {
$info['aac']['program_configs'][$i]['mono_mixdown_element_number'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
$info['aac']['program_configs'][$i]['stereo_mixdown_present'] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
if ($info['aac']['program_configs'][$i]['stereo_mixdown_present']) {
$info['aac']['program_configs'][$i]['stereo_mixdown_element_number'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
$info['aac']['program_configs'][$i]['matrix_mixdown_idx_present'] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
if ($info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
$info['aac']['program_configs'][$i]['matrix_mixdown_idx'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
$bitoffset += 2;
$info['aac']['program_configs'][$i]['pseudo_surround_enable'] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
}
for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
$info['aac']['program_configs'][$i]['front_element_is_cpe'][$j] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
$info['aac']['program_configs'][$i]['front_element_tag_select'][$j] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
$info['aac']['program_configs'][$i]['side_element_is_cpe'][$j] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
$info['aac']['program_configs'][$i]['side_element_tag_select'][$j] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
$info['aac']['program_configs'][$i]['back_element_is_cpe'][$j] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
$info['aac']['program_configs'][$i]['back_element_tag_select'][$j] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
$info['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
$info['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
$info['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j] = (bool) Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
$bitoffset += 1;
$info['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
$bitoffset += 4;
}
$bitoffset = ceil($bitoffset / 8) * 8;
$info['aac']['program_configs'][$i]['comment_field_bytes'] = Utils::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
$bitoffset += 8;
$info['aac']['program_configs'][$i]['comment_field'] = Utils::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $info['aac']['program_configs'][$i]['comment_field_bytes']));
$bitoffset += 8 * $info['aac']['program_configs'][$i]['comment_field_bytes'];
$info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['program_configs'][$i]['object_type'], $info['aac']['header']['mpeg_version']);
$info['aac']['program_configs'][$i]['sampling_frequency'] = self::AACsampleRateLookup($info['aac']['program_configs'][$i]['sampling_frequency_index']);
$info['audio']['sample_rate'] = $info['aac']['program_configs'][$i]['sampling_frequency'];
$info['audio']['channels'] = self::AACchannelCountCalculate($info['aac']['program_configs'][$i]);
if ($info['aac']['program_configs'][$i]['comment_field']) {
$info['aac']['comments'][] = $info['aac']['program_configs'][$i]['comment_field'];
}
}
$info['playtime_seconds'] = ($info['avdataend'] - $info['avdataoffset']) * 8 / $info['audio']['bitrate'];
$info['audio']['encoder_options'] = $info['aac']['header_type'] . ' ' . $info['aac']['header']['profile'];
return true;
} else {
unset($info['fileformat']);
unset($info['aac']);
$info['error'][] = 'AAC-ADIF synch not found at offset ' . $info['avdataoffset'] . ' (expected "ADIF", found "' . substr($AACheader, 0, 4) . '" instead)';
return false;
}
}
