rlm@3: <?php
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | PHP version 5                                                        |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen                 |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | This source file is subject to version 2 of the GPL license,         |
rlm@3: // | that is bundled with this package in the file license.txt and is     |
rlm@3: // | available through the world-wide-web at the following url:           |
rlm@3: // | http://www.gnu.org/copyleft/gpl.html                                 |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org    |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | Authors: James Heinrich <infoØgetid3*org>                            |
rlm@3: // |          Allan Hansen <ahØartemis*dk>                                |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | module.audio.aac_adif.php                                            |
rlm@3: // | Module for analyzing AAC files with ADIF header.                     |
rlm@3: // | dependencies: NONE                                                   |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: //
rlm@3: // $Id: module.audio.aac_adif.php,v 1.3 2006/11/02 10:48:00 ah Exp $
rlm@3: 
rlm@3:         
rlm@3:         
rlm@3: class getid3_aac_adif extends getid3_handler
rlm@3: {
rlm@3: 
rlm@3:     public function Analyze() {
rlm@3: 
rlm@3:         $getid3 = $this->getid3;    
rlm@3: 
rlm@3:         // http://faac.sourceforge.net/wiki/index.php?page=ADIF
rlm@3:         // http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
rlm@3:         // adif_header() {
rlm@3:         //     adif_id                                32
rlm@3:         //     copyright_id_present                    1
rlm@3:         //     if( copyright_id_present )
rlm@3:         //         copyright_id                       72
rlm@3:         //     original_copy                           1
rlm@3:         //     home                                    1
rlm@3:         //     bitstream_type                          1
rlm@3:         //     bitrate                                23
rlm@3:         //     num_program_config_elements             4
rlm@3:         //     for (i = 0; i < num_program_config_elements + 1; i++ ) {
rlm@3:         //         if( bitstream_type == '0' )
rlm@3:         //             adif_buffer_fullness           20
rlm@3:         //         program_config_element()
rlm@3:         //     }
rlm@3:         // }
rlm@3:         
rlm@3: 
rlm@3:         $getid3->info['fileformat']          = 'aac';
rlm@3:         $getid3->info['audio']['dataformat'] = 'aac';
rlm@3:         $getid3->info['audio']['lossless']   = false;
rlm@3:         
rlm@3:         $getid3->info['aac']['header'] = array () ;
rlm@3:         $info_aac        = &$getid3->info['aac'];
rlm@3:         $info_aac_header = & $info_aac['header'];
rlm@3: 
rlm@3:         fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);
rlm@3:         $aac_header_bitstream = getid3_lib::BigEndian2Bin(fread($getid3->fp, 1024));
rlm@3:         
rlm@3:         $info_aac['header_type']            = 'ADIF';
rlm@3:         $info_aac_header['mpeg_version'] = 4;
rlm@3:         $bit_offset = 32;
rlm@3: 
rlm@3:         $info_aac_header['copyright'] = $aac_header_bitstream{$bit_offset++} == '1';
rlm@3:         if ($info_aac_header['copyright']) {
rlm@3:             $info_aac_header['copyright_id'] = getid3_aac_adif::Bin2String(substr($aac_header_bitstream, $bit_offset, 72));
rlm@3:             $bit_offset += 72;
rlm@3:         }
rlm@3:         
rlm@3:         $info_aac_header['original_copy'] = $aac_header_bitstream{$bit_offset++} == '1';
rlm@3:         $info_aac_header['home']          = $aac_header_bitstream{$bit_offset++} == '1';
rlm@3:         $info_aac_header['is_vbr']        = $aac_header_bitstream{$bit_offset++} == '1';
rlm@3: 
rlm@3:         if ($info_aac_header['is_vbr']) {
rlm@3:             $getid3->info['audio']['bitrate_mode'] = 'vbr';
rlm@3:             $info_aac_header['bitrate_max']     = bindec(substr($aac_header_bitstream, $bit_offset, 23));
rlm@3:             $bit_offset += 23;
rlm@3:         } 
rlm@3:         else {
rlm@3:             $getid3->info['audio']['bitrate_mode'] = 'cbr';
rlm@3:             $info_aac_header['bitrate']         = bindec(substr($aac_header_bitstream, $bit_offset, 23));
rlm@3:             $bit_offset += 23;
rlm@3:             $getid3->info['audio']['bitrate']      = $info_aac_header['bitrate'];
rlm@3:         }
rlm@3:         
rlm@3:         $info_aac_header['num_program_configs'] = 1 + bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:         $bit_offset += 4;
rlm@3: 
rlm@3:         for ($i = 0; $i < $info_aac_header['num_program_configs']; $i++) {
rlm@3: 
rlm@3:             // http://www.audiocoding.com/wiki/index.php?page=program_config_element
rlm@3: 
rlm@3:             // buffer_fullness                       20
rlm@3: 
rlm@3:             // element_instance_tag                   4
rlm@3:             // object_type                            2
rlm@3:             // sampling_frequency_index               4
rlm@3:             // num_front_channel_elements             4
rlm@3:             // num_side_channel_elements              4
rlm@3:             // num_back_channel_elements              4
rlm@3:             // num_lfe_channel_elements               2
rlm@3:             // num_assoc_data_elements                3
rlm@3:             // num_valid_cc_elements                  4
rlm@3:             // mono_mixdown_present                   1
rlm@3:             // mono_mixdown_element_number            4   if mono_mixdown_present == 1
rlm@3:             // stereo_mixdown_present                 1
rlm@3:             // stereo_mixdown_element_number          4   if stereo_mixdown_present == 1
rlm@3:             // matrix_mixdown_idx_present             1
rlm@3:             // matrix_mixdown_idx                     2   if matrix_mixdown_idx_present == 1
rlm@3:             // pseudo_surround_enable                 1   if matrix_mixdown_idx_present == 1
rlm@3:             // for (i = 0; i < num_front_channel_elements; i++) {
rlm@3:             //     front_element_is_cpe[i]            1
rlm@3:             //     front_element_tag_select[i]        4
rlm@3:             // }
rlm@3:             // for (i = 0; i < num_side_channel_elements; i++) {
rlm@3:             //     side_element_is_cpe[i]             1
rlm@3:             //     side_element_tag_select[i]         4
rlm@3:             // }
rlm@3:             // for (i = 0; i < num_back_channel_elements; i++) {
rlm@3:             //     back_element_is_cpe[i]             1
rlm@3:             //     back_element_tag_select[i]         4
rlm@3:             // }
rlm@3:             // for (i = 0; i < num_lfe_channel_elements; i++) {
rlm@3:             //     lfe_element_tag_select[i]          4
rlm@3:             // }
rlm@3:             // for (i = 0; i < num_assoc_data_elements; i++) {
rlm@3:             //     assoc_data_element_tag_select[i]   4
rlm@3:             // }
rlm@3:             // for (i = 0; i < num_valid_cc_elements; i++) {
rlm@3:             //     cc_element_is_ind_sw[i]            1
rlm@3:             //     valid_cc_element_tag_select[i]     4
rlm@3:             // }
rlm@3:             // byte_alignment()                       VAR
rlm@3:             // comment_field_bytes                    8
rlm@3:             // for (i = 0; i < comment_field_bytes; i++) {
rlm@3:             //     comment_field_data[i]              8
rlm@3:             // }
rlm@3:             
rlm@3:             $info_aac['program_configs'][$i] = array ();
rlm@3:             $info_aac_program_configs_i = &$info_aac['program_configs'][$i];
rlm@3: 
rlm@3:             if (!$info_aac_header['is_vbr']) {
rlm@3:                 $info_aac_program_configs_i['buffer_fullness']        = bindec(substr($aac_header_bitstream, $bit_offset, 20));
rlm@3:                 $bit_offset += 20;
rlm@3:             }
rlm@3:                 
rlm@3:             $info_aac_program_configs_i['element_instance_tag']       = bindec(substr($aac_header_bitstream, $bit_offset,      4));
rlm@3:             $info_aac_program_configs_i['object_type']                = bindec(substr($aac_header_bitstream, $bit_offset +  4, 2));
rlm@3:             $info_aac_program_configs_i['sampling_frequency_index']   = bindec(substr($aac_header_bitstream, $bit_offset +  6, 4));
rlm@3:             $info_aac_program_configs_i['num_front_channel_elements'] = bindec(substr($aac_header_bitstream, $bit_offset + 10, 4));
rlm@3:             $info_aac_program_configs_i['num_side_channel_elements']  = bindec(substr($aac_header_bitstream, $bit_offset + 14, 4));
rlm@3:             $info_aac_program_configs_i['num_back_channel_elements']  = bindec(substr($aac_header_bitstream, $bit_offset + 18, 4));
rlm@3:             $info_aac_program_configs_i['num_lfe_channel_elements']   = bindec(substr($aac_header_bitstream, $bit_offset + 22, 2));
rlm@3:             $info_aac_program_configs_i['num_assoc_data_elements']    = bindec(substr($aac_header_bitstream, $bit_offset + 24, 3));
rlm@3:             $info_aac_program_configs_i['num_valid_cc_elements']      = bindec(substr($aac_header_bitstream, $bit_offset + 27, 4));
rlm@3:             $bit_offset += 31;
rlm@3:             
rlm@3:             $info_aac_program_configs_i['mono_mixdown_present'] = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:             if ($info_aac_program_configs_i['mono_mixdown_present']) {
rlm@3:                 $info_aac_program_configs_i['mono_mixdown_element_number'] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             
rlm@3:             $info_aac_program_configs_i['stereo_mixdown_present'] = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:             if ($info_aac_program_configs_i['stereo_mixdown_present']) {
rlm@3:                 $info_aac_program_configs_i['stereo_mixdown_element_number'] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             
rlm@3:             $info_aac_program_configs_i['matrix_mixdown_idx_present'] = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:             if ($info_aac_program_configs_i['matrix_mixdown_idx_present']) {
rlm@3:                 $info_aac_program_configs_i['matrix_mixdown_idx']     = bindec(substr($aac_header_bitstream, $bit_offset, 2));
rlm@3:                 $bit_offset += 2;
rlm@3:                 $info_aac_program_configs_i['pseudo_surround_enable'] = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:             }
rlm@3:             
rlm@3:             for ($j = 0; $j < $info_aac_program_configs_i['num_front_channel_elements']; $j++) {
rlm@3:                 $info_aac_program_configs_i['front_element_is_cpe'][$j]     = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:                 $info_aac_program_configs_i['front_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             for ($j = 0; $j < $info_aac_program_configs_i['num_side_channel_elements']; $j++) {
rlm@3:                 $info_aac_program_configs_i['side_element_is_cpe'][$j]     = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:                 $info_aac_program_configs_i['side_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             for ($j = 0; $j < $info_aac_program_configs_i['num_back_channel_elements']; $j++) {
rlm@3:                 $info_aac_program_configs_i['back_element_is_cpe'][$j]     = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:                 $info_aac_program_configs_i['back_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             for ($j = 0; $j < $info_aac_program_configs_i['num_lfe_channel_elements']; $j++) {
rlm@3:                 $info_aac_program_configs_i['lfe_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             for ($j = 0; $j < $info_aac_program_configs_i['num_assoc_data_elements']; $j++) {
rlm@3:                 $info_aac_program_configs_i['assoc_data_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3:             for ($j = 0; $j < $info_aac_program_configs_i['num_valid_cc_elements']; $j++) {
rlm@3:                 $info_aac_program_configs_i['cc_element_is_ind_sw'][$j]          = $aac_header_bitstream{$bit_offset++} == 1;
rlm@3:                 $info_aac_program_configs_i['valid_cc_element_tag_select'][$j]   = bindec(substr($aac_header_bitstream, $bit_offset, 4));
rlm@3:                 $bit_offset += 4;
rlm@3:             }
rlm@3: 
rlm@3:             $bit_offset = ceil($bit_offset / 8) * 8;
rlm@3: 
rlm@3:             $info_aac_program_configs_i['comment_field_bytes'] = bindec(substr($aac_header_bitstream, $bit_offset, 8));
rlm@3:             $bit_offset += 8;
rlm@3:             
rlm@3:             $info_aac_program_configs_i['comment_field'] = getid3_aac_adif::Bin2String(substr($aac_header_bitstream, $bit_offset, 8 * $info_aac_program_configs_i['comment_field_bytes']));
rlm@3:             $bit_offset += 8 * $info_aac_program_configs_i['comment_field_bytes'];
rlm@3: 
rlm@3:             $info_aac_header['profile_text']                  = getid3_aac_adif::AACprofileLookup($info_aac_program_configs_i['object_type'], $info_aac_header['mpeg_version']);
rlm@3:             $info_aac_program_configs_i['sampling_frequency'] = $getid3->info['audio']['sample_rate'] = getid3_aac_adif::AACsampleRateLookup($info_aac_program_configs_i['sampling_frequency_index']);
rlm@3:             $getid3->info['audio']['channels']                = getid3_aac_adif::AACchannelCountCalculate($info_aac_program_configs_i);
rlm@3:             
rlm@3:             if ($info_aac_program_configs_i['comment_field']) {
rlm@3:                 $info_aac['comments'][] = $info_aac_program_configs_i['comment_field'];
rlm@3:             }
rlm@3:         }
rlm@3:         
rlm@3:         $getid3->info['playtime_seconds'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['audio']['bitrate'];
rlm@3:         $getid3->info['audio']['encoder_options'] = $info_aac['header_type'].' '.$info_aac_header['profile_text'];
rlm@3: 
rlm@3:         return true;
rlm@3:     }
rlm@3: 
rlm@3: 
rlm@3: 
rlm@3:     public static function Bin2String($bin_string) {
rlm@3:         // return 'hi' for input of '0110100001101001'
rlm@3:         $string = '';
rlm@3:         $bin_string_reversed = strrev($bin_string);
rlm@3:         for ($i = 0; $i < strlen($bin_string_reversed); $i += 8) {
rlm@3:             $string = chr(bindec(strrev(substr($bin_string_reversed, $i, 8)))).$string;
rlm@3:         }
rlm@3:         return $string;
rlm@3:     }
rlm@3:     
rlm@3:     
rlm@3:     
rlm@3:     public static function AACsampleRateLookup($samplerate_id) {
rlm@3:         
rlm@3:         static $lookup = array (
rlm@3:             0  => 96000,
rlm@3:             1  => 88200,
rlm@3:             2  => 64000,
rlm@3:             3  => 48000,
rlm@3:             4  => 44100,
rlm@3:             5  => 32000,
rlm@3:             6  => 24000,
rlm@3:             7  => 22050,
rlm@3:             8  => 16000,
rlm@3:             9  => 12000,
rlm@3:             10 => 11025,
rlm@3:             11 => 8000,
rlm@3:             12 => 0,
rlm@3:             13 => 0,
rlm@3:             14 => 0,
rlm@3:             15 => 0
rlm@3:         );
rlm@3:         return (isset($lookup[$samplerate_id]) ? $lookup[$samplerate_id] : 'invalid');
rlm@3:     }
rlm@3: 
rlm@3: 
rlm@3: 
rlm@3:     public static function AACprofileLookup($profile_id, $mpeg_version) {
rlm@3:         
rlm@3:         static $lookup = array (
rlm@3:             2 => array ( 
rlm@3:                 0 => 'Main profile',
rlm@3:                 1 => 'Low Complexity profile (LC)',
rlm@3:                 2 => 'Scalable Sample Rate profile (SSR)',
rlm@3:                 3 => '(reserved)'
rlm@3:             ),            
rlm@3:             4 => array (
rlm@3:                 0 => 'AAC_MAIN',
rlm@3:                 1 => 'AAC_LC',
rlm@3:                 2 => 'AAC_SSR',
rlm@3:                 3 => 'AAC_LTP'
rlm@3:             )
rlm@3:         );
rlm@3:         return (isset($lookup[$mpeg_version][$profile_id]) ? $lookup[$mpeg_version][$profile_id] : 'invalid');
rlm@3:     }
rlm@3: 
rlm@3: 
rlm@3: 
rlm@3:     public static function AACchannelCountCalculate($program_configs) {
rlm@3:         
rlm@3:         $channels = 0;
rlm@3:         
rlm@3:         foreach (array ('front', 'side', 'back') as $placement) {
rlm@3:             for ($i = 0; $i < $program_configs['num_'.$placement.'_channel_elements']; $i++) {
rlm@3:                 
rlm@3:                 // Each element is channel pair (CPE = Channel Pair Element)
rlm@3:                 $channels += 1 + ($program_configs[$placement.'_element_is_cpe'][$i] ? 1 : 0);
rlm@3:             }
rlm@3:         }
rlm@3:         
rlm@3:         return $channels + $program_configs['num_lfe_channel_elements'];
rlm@3:     }
rlm@3: 
rlm@3: }
rlm@3: 
rlm@3: 
rlm@3: ?>