Mercurial > judyates

     1 <?php

     2 // +----------------------------------------------------------------------+

     3 // | PHP version 5                                                        |

     4 // +----------------------------------------------------------------------+

     5 // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen                 |

     6 // +----------------------------------------------------------------------+

     7 // | This source file is subject to version 2 of the GPL license,         |

     8 // | that is bundled with this package in the file license.txt and is     |

     9 // | available through the world-wide-web at the following url:           |

    10 // | http://www.gnu.org/copyleft/gpl.html                                 |

    11 // +----------------------------------------------------------------------+

    12 // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org    |

    13 // +----------------------------------------------------------------------+

    14 // | Authors: James Heinrich <infoØgetid3*org>                            |

    15 // |          Allan Hansen <ahØartemis*dk>                                |

    16 // +----------------------------------------------------------------------+

    17 // | module.audio.aac_adif.php                                            |

    18 // | Module for analyzing AAC files with ADIF header.                     |

    19 // | dependencies: NONE                                                   |

    20 // +----------------------------------------------------------------------+

    21 //

    22 // $Id: module.audio.aac_adif.php,v 1.3 2006/11/02 10:48:00 ah Exp $

    23 

    24         

    25         

    26 class getid3_aac_adif extends getid3_handler

    27 {

    28 

    29     public function Analyze() {

    30 

    31         $getid3 = $this->getid3;    

    32 

    33         // http://faac.sourceforge.net/wiki/index.php?page=ADIF

    34         // http://libmpeg.org/mpeg4/doc/w2203tfs.pdf

    35         // adif_header() {

    36         //     adif_id                                32

    37         //     copyright_id_present                    1

    38         //     if( copyright_id_present )

    39         //         copyright_id                       72

    40         //     original_copy                           1

    41         //     home                                    1

    42         //     bitstream_type                          1

    43         //     bitrate                                23

    44         //     num_program_config_elements             4

    45         //     for (i = 0; i < num_program_config_elements + 1; i++ ) {

    46         //         if( bitstream_type == '0' )

    47         //             adif_buffer_fullness           20

    48         //         program_config_element()

    49         //     }

    50         // }

    51         

    52 

    53         $getid3->info['fileformat']          = 'aac';

    54         $getid3->info['audio']['dataformat'] = 'aac';

    55         $getid3->info['audio']['lossless']   = false;

    56         

    57         $getid3->info['aac']['header'] = array () ;

    58         $info_aac        = &$getid3->info['aac'];

    59         $info_aac_header = & $info_aac['header'];

    60 

    61         fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);

    62         $aac_header_bitstream = getid3_lib::BigEndian2Bin(fread($getid3->fp, 1024));

    63         

    64         $info_aac['header_type']            = 'ADIF';

    65         $info_aac_header['mpeg_version'] = 4;

    66         $bit_offset = 32;

    67 

    68         $info_aac_header['copyright'] = $aac_header_bitstream{$bit_offset++} == '1';

    69         if ($info_aac_header['copyright']) {

    70             $info_aac_header['copyright_id'] = getid3_aac_adif::Bin2String(substr($aac_header_bitstream, $bit_offset, 72));

    71             $bit_offset += 72;

    72         }

    73         

    74         $info_aac_header['original_copy'] = $aac_header_bitstream{$bit_offset++} == '1';

    75         $info_aac_header['home']          = $aac_header_bitstream{$bit_offset++} == '1';

    76         $info_aac_header['is_vbr']        = $aac_header_bitstream{$bit_offset++} == '1';

    77 

    78         if ($info_aac_header['is_vbr']) {

    79             $getid3->info['audio']['bitrate_mode'] = 'vbr';

    80             $info_aac_header['bitrate_max']     = bindec(substr($aac_header_bitstream, $bit_offset, 23));

    81             $bit_offset += 23;

    82         } 

    83         else {

    84             $getid3->info['audio']['bitrate_mode'] = 'cbr';

    85             $info_aac_header['bitrate']         = bindec(substr($aac_header_bitstream, $bit_offset, 23));

    86             $bit_offset += 23;

    87             $getid3->info['audio']['bitrate']      = $info_aac_header['bitrate'];

    88         }

    89         

    90         $info_aac_header['num_program_configs'] = 1 + bindec(substr($aac_header_bitstream, $bit_offset, 4));

    91         $bit_offset += 4;

    92 

    93         for ($i = 0; $i < $info_aac_header['num_program_configs']; $i++) {

    94 

    95             // http://www.audiocoding.com/wiki/index.php?page=program_config_element

    96 

    97             // buffer_fullness                       20

    98 

    99             // element_instance_tag                   4

   100             // object_type                            2

   101             // sampling_frequency_index               4

   102             // num_front_channel_elements             4

   103             // num_side_channel_elements              4

   104             // num_back_channel_elements              4

   105             // num_lfe_channel_elements               2

   106             // num_assoc_data_elements                3

   107             // num_valid_cc_elements                  4

   108             // mono_mixdown_present                   1

   109             // mono_mixdown_element_number            4   if mono_mixdown_present == 1

   110             // stereo_mixdown_present                 1

   111             // stereo_mixdown_element_number          4   if stereo_mixdown_present == 1

   112             // matrix_mixdown_idx_present             1

   113             // matrix_mixdown_idx                     2   if matrix_mixdown_idx_present == 1

   114             // pseudo_surround_enable                 1   if matrix_mixdown_idx_present == 1

   115             // for (i = 0; i < num_front_channel_elements; i++) {

   116             //     front_element_is_cpe[i]            1

   117             //     front_element_tag_select[i]        4

   118             // }

   119             // for (i = 0; i < num_side_channel_elements; i++) {

   120             //     side_element_is_cpe[i]             1

   121             //     side_element_tag_select[i]         4

   122             // }

   123             // for (i = 0; i < num_back_channel_elements; i++) {

   124             //     back_element_is_cpe[i]             1

   125             //     back_element_tag_select[i]         4

   126             // }

   127             // for (i = 0; i < num_lfe_channel_elements; i++) {

   128             //     lfe_element_tag_select[i]          4

   129             // }

   130             // for (i = 0; i < num_assoc_data_elements; i++) {

   131             //     assoc_data_element_tag_select[i]   4

   132             // }

   133             // for (i = 0; i < num_valid_cc_elements; i++) {

   134             //     cc_element_is_ind_sw[i]            1

   135             //     valid_cc_element_tag_select[i]     4

   136             // }

   137             // byte_alignment()                       VAR

   138             // comment_field_bytes                    8

   139             // for (i = 0; i < comment_field_bytes; i++) {

   140             //     comment_field_data[i]              8

   141             // }

   142             

   143             $info_aac['program_configs'][$i] = array ();

   144             $info_aac_program_configs_i = &$info_aac['program_configs'][$i];

   145 

   146             if (!$info_aac_header['is_vbr']) {

   147                 $info_aac_program_configs_i['buffer_fullness']        = bindec(substr($aac_header_bitstream, $bit_offset, 20));

   148                 $bit_offset += 20;

   149             }

   150                 

   151             $info_aac_program_configs_i['element_instance_tag']       = bindec(substr($aac_header_bitstream, $bit_offset,      4));

   152             $info_aac_program_configs_i['object_type']                = bindec(substr($aac_header_bitstream, $bit_offset +  4, 2));

   153             $info_aac_program_configs_i['sampling_frequency_index']   = bindec(substr($aac_header_bitstream, $bit_offset +  6, 4));

   154             $info_aac_program_configs_i['num_front_channel_elements'] = bindec(substr($aac_header_bitstream, $bit_offset + 10, 4));

   155             $info_aac_program_configs_i['num_side_channel_elements']  = bindec(substr($aac_header_bitstream, $bit_offset + 14, 4));

   156             $info_aac_program_configs_i['num_back_channel_elements']  = bindec(substr($aac_header_bitstream, $bit_offset + 18, 4));

   157             $info_aac_program_configs_i['num_lfe_channel_elements']   = bindec(substr($aac_header_bitstream, $bit_offset + 22, 2));

   158             $info_aac_program_configs_i['num_assoc_data_elements']    = bindec(substr($aac_header_bitstream, $bit_offset + 24, 3));

   159             $info_aac_program_configs_i['num_valid_cc_elements']      = bindec(substr($aac_header_bitstream, $bit_offset + 27, 4));

   160             $bit_offset += 31;

   161             

   162             $info_aac_program_configs_i['mono_mixdown_present'] = $aac_header_bitstream{$bit_offset++} == 1;

   163             if ($info_aac_program_configs_i['mono_mixdown_present']) {

   164                 $info_aac_program_configs_i['mono_mixdown_element_number'] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   165                 $bit_offset += 4;

   166             }

   167             

   168             $info_aac_program_configs_i['stereo_mixdown_present'] = $aac_header_bitstream{$bit_offset++} == 1;

   169             if ($info_aac_program_configs_i['stereo_mixdown_present']) {

   170                 $info_aac_program_configs_i['stereo_mixdown_element_number'] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   171                 $bit_offset += 4;

   172             }

   173             

   174             $info_aac_program_configs_i['matrix_mixdown_idx_present'] = $aac_header_bitstream{$bit_offset++} == 1;

   175             if ($info_aac_program_configs_i['matrix_mixdown_idx_present']) {

   176                 $info_aac_program_configs_i['matrix_mixdown_idx']     = bindec(substr($aac_header_bitstream, $bit_offset, 2));

   177                 $bit_offset += 2;

   178                 $info_aac_program_configs_i['pseudo_surround_enable'] = $aac_header_bitstream{$bit_offset++} == 1;

   179             }

   180             

   181             for ($j = 0; $j < $info_aac_program_configs_i['num_front_channel_elements']; $j++) {

   182                 $info_aac_program_configs_i['front_element_is_cpe'][$j]     = $aac_header_bitstream{$bit_offset++} == 1;

   183                 $info_aac_program_configs_i['front_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   184                 $bit_offset += 4;

   185             }

   186             for ($j = 0; $j < $info_aac_program_configs_i['num_side_channel_elements']; $j++) {

   187                 $info_aac_program_configs_i['side_element_is_cpe'][$j]     = $aac_header_bitstream{$bit_offset++} == 1;

   188                 $info_aac_program_configs_i['side_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   189                 $bit_offset += 4;

   190             }

   191             for ($j = 0; $j < $info_aac_program_configs_i['num_back_channel_elements']; $j++) {

   192                 $info_aac_program_configs_i['back_element_is_cpe'][$j]     = $aac_header_bitstream{$bit_offset++} == 1;

   193                 $info_aac_program_configs_i['back_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   194                 $bit_offset += 4;

   195             }

   196             for ($j = 0; $j < $info_aac_program_configs_i['num_lfe_channel_elements']; $j++) {

   197                 $info_aac_program_configs_i['lfe_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   198                 $bit_offset += 4;

   199             }

   200             for ($j = 0; $j < $info_aac_program_configs_i['num_assoc_data_elements']; $j++) {

   201                 $info_aac_program_configs_i['assoc_data_element_tag_select'][$j] = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   202                 $bit_offset += 4;

   203             }

   204             for ($j = 0; $j < $info_aac_program_configs_i['num_valid_cc_elements']; $j++) {

   205                 $info_aac_program_configs_i['cc_element_is_ind_sw'][$j]          = $aac_header_bitstream{$bit_offset++} == 1;

   206                 $info_aac_program_configs_i['valid_cc_element_tag_select'][$j]   = bindec(substr($aac_header_bitstream, $bit_offset, 4));

   207                 $bit_offset += 4;

   208             }

   209 

   210             $bit_offset = ceil($bit_offset / 8) * 8;

   211 

   212             $info_aac_program_configs_i['comment_field_bytes'] = bindec(substr($aac_header_bitstream, $bit_offset, 8));

   213             $bit_offset += 8;

   214             

   215             $info_aac_program_configs_i['comment_field'] = getid3_aac_adif::Bin2String(substr($aac_header_bitstream, $bit_offset, 8 * $info_aac_program_configs_i['comment_field_bytes']));

   216             $bit_offset += 8 * $info_aac_program_configs_i['comment_field_bytes'];

   217 

   218             $info_aac_header['profile_text']                  = getid3_aac_adif::AACprofileLookup($info_aac_program_configs_i['object_type'], $info_aac_header['mpeg_version']);

   219             $info_aac_program_configs_i['sampling_frequency'] = $getid3->info['audio']['sample_rate'] = getid3_aac_adif::AACsampleRateLookup($info_aac_program_configs_i['sampling_frequency_index']);

   220             $getid3->info['audio']['channels']                = getid3_aac_adif::AACchannelCountCalculate($info_aac_program_configs_i);

   221             

   222             if ($info_aac_program_configs_i['comment_field']) {

   223                 $info_aac['comments'][] = $info_aac_program_configs_i['comment_field'];

   224             }

   225         }

   226         

   227         $getid3->info['playtime_seconds'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['audio']['bitrate'];

   228         $getid3->info['audio']['encoder_options'] = $info_aac['header_type'].' '.$info_aac_header['profile_text'];

   229 

   230         return true;

   231     }

   232 

   233 

   234 

   235     public static function Bin2String($bin_string) {

   236         // return 'hi' for input of '0110100001101001'

   237         $string = '';

   238         $bin_string_reversed = strrev($bin_string);

   239         for ($i = 0; $i < strlen($bin_string_reversed); $i += 8) {

   240             $string = chr(bindec(strrev(substr($bin_string_reversed, $i, 8)))).$string;

   241         }

   242         return $string;

   243     }

   244     

   245     

   246     

   247     public static function AACsampleRateLookup($samplerate_id) {

   248         

   249         static $lookup = array (

   250             0  => 96000,

   251             1  => 88200,

   252             2  => 64000,

   253             3  => 48000,

   254             4  => 44100,

   255             5  => 32000,

   256             6  => 24000,

   257             7  => 22050,

   258             8  => 16000,

   259             9  => 12000,

   260             10 => 11025,

   261             11 => 8000,

   262             12 => 0,

   263             13 => 0,

   264             14 => 0,

   265             15 => 0

   266         );

   267         return (isset($lookup[$samplerate_id]) ? $lookup[$samplerate_id] : 'invalid');

   268     }

   269 

   270 

   271 

   272     public static function AACprofileLookup($profile_id, $mpeg_version) {

   273         

   274         static $lookup = array (

   275             2 => array ( 

   276                 0 => 'Main profile',

   277                 1 => 'Low Complexity profile (LC)',

   278                 2 => 'Scalable Sample Rate profile (SSR)',

   279                 3 => '(reserved)'

   280             ),            

   281             4 => array (

   282                 0 => 'AAC_MAIN',

   283                 1 => 'AAC_LC',

   284                 2 => 'AAC_SSR',

   285                 3 => 'AAC_LTP'

   286             )

   287         );

   288         return (isset($lookup[$mpeg_version][$profile_id]) ? $lookup[$mpeg_version][$profile_id] : 'invalid');

   289     }

   290 

   291 

   292 

   293     public static function AACchannelCountCalculate($program_configs) {

   294         

   295         $channels = 0;

   296         

   297         foreach (array ('front', 'side', 'back') as $placement) {

   298             for ($i = 0; $i < $program_configs['num_'.$placement.'_channel_elements']; $i++) {

   299                 

   300                 // Each element is channel pair (CPE = Channel Pair Element)

   301                 $channels += 1 + ($program_configs[$placement.'_element_is_cpe'][$i] ? 1 : 0);

   302             }

   303         }

   304         

   305         return $channels + $program_configs['num_lfe_channel_elements'];

   306     }

   307 

   308 }

   309 

   310 

   311 ?>
author	Robert McIntyre <rlm@mit.edu>
date	Mon, 11 Jul 2011 03:06:13 -0400
parents	3f6b44aa6b35
children