www/plugins-dist/medias/lib/getid3/module.audio.aac.php

   1 <?php
   2
   3 /////////////////////////////////////////////////////////////////
   4 /// getID3() by James Heinrich <info@getid3.org>               //
   5 //  available at https://github.com/JamesHeinrich/getID3       //
   6 //            or https://www.getid3.org                        //
   7 //            or http://getid3.sourceforge.net                 //
   8 //  see readme.txt for more details                            //
   9 /////////////////////////////////////////////////////////////////
  10 //                                                             //
  11 // module.audio.aac.php                                        //
  12 // module for analyzing AAC Audio files                        //
  13 // dependencies: NONE                                          //
  14 //                                                            ///
  15 /////////////////////////////////////////////////////////////////
  16
  17 if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers
  18         exit;
  19 }
  20
  21 class getid3_aac extends getid3_handler
  22 {
  23         /**
  24          * @return bool
  25          */
  26         public function Analyze() {
  27                 $info = &$this->getid3->info;
  28                 $this->fseek($info['avdataoffset']);
  29                 if ($this->fread(4) == 'ADIF') {
  30                         $this->getAACADIFheaderFilepointer();
  31                 } else {
  32                         $this->getAACADTSheaderFilepointer();
  33                 }
  34                 return true;
  35         }
  36
  37         /**
  38          * @return bool
  39          */
  40         public function getAACADIFheaderFilepointer() {
  41                 $info = &$this->getid3->info;
  42                 $info['fileformat']          = 'aac';
  43                 $info['audio']['dataformat'] = 'aac';
  44                 $info['audio']['lossless']   = false;
  45
  46                 $this->fseek($info['avdataoffset']);
  47                 $AACheader = $this->fread(1024);
  48                 $offset    = 0;
  49
  50                 if (substr($AACheader, 0, 4) == 'ADIF') {
  51
  52                         // http://faac.sourceforge.net/wiki/index.php?page=ADIF
  53
  54                         // http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
  55                         // adif_header() {
  56                         //     adif_id                                32
  57                         //     copyright_id_present                    1
  58                         //     if( copyright_id_present )
  59                         //         copyright_id                       72
  60                         //     original_copy                           1
  61                         //     home                                    1
  62                         //     bitstream_type                          1
  63                         //     bitrate                                23
  64                         //     num_program_config_elements             4
  65                         //     for (i = 0; i < num_program_config_elements + 1; i++ ) {
  66                         //         if( bitstream_type == '0' )
  67                         //             adif_buffer_fullness           20
  68                         //         program_config_element()
  69                         //     }
  70                         // }
  71
  72                         $AACheaderBitstream = getid3_lib::BigEndian2Bin($AACheader);
  73                         $bitoffset          = 0;
  74
  75                         $info['aac']['header_type']                   = 'ADIF';
  76                         $bitoffset += 32;
  77                         $info['aac']['header']['mpeg_version']        = 4;
  78
  79                         $info['aac']['header']['copyright']           = substr($AACheaderBitstream, $bitoffset, 1) == '1';
  80                         $bitoffset += 1;
  81                         if ($info['aac']['header']['copyright']) {
  82                                 $info['aac']['header']['copyright_id']    = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
  83                                 $bitoffset += 72;
  84                         }
  85                         $info['aac']['header']['original_copy']       = substr($AACheaderBitstream, $bitoffset, 1) == '1';
  86                         $bitoffset += 1;
  87                         $info['aac']['header']['home']                = substr($AACheaderBitstream, $bitoffset, 1) == '1';
  88                         $bitoffset += 1;
  89                         $info['aac']['header']['is_vbr']              = substr($AACheaderBitstream, $bitoffset, 1) == '1';
  90                         $bitoffset += 1;
  91                         if ($info['aac']['header']['is_vbr']) {
  92                                 $info['audio']['bitrate_mode']            = 'vbr';
  93                                 $info['aac']['header']['bitrate_max']     = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
  94                                 $bitoffset += 23;
  95                         } else {
  96                                 $info['audio']['bitrate_mode']            = 'cbr';
  97                                 $info['aac']['header']['bitrate']         = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
  98                                 $bitoffset += 23;
  99                                 $info['audio']['bitrate']                 = $info['aac']['header']['bitrate'];
 100                         }
 101                         if ($info['audio']['bitrate'] == 0) {
 102                                 $this->error('Corrupt AAC file: bitrate_audio == zero');
 103                                 return false;
 104                         }
 105                         $info['aac']['header']['num_program_configs'] = 1 + getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 106                         $bitoffset += 4;
 107
 108                         for ($i = 0; $i < $info['aac']['header']['num_program_configs']; $i++) {
 109                                 // http://www.audiocoding.com/wiki/index.php?page=program_config_element
 110
 111                                 // buffer_fullness                       20
 112
 113                                 // element_instance_tag                   4
 114                                 // object_type                            2
 115                                 // sampling_frequency_index               4
 116                                 // num_front_channel_elements             4
 117                                 // num_side_channel_elements              4
 118                                 // num_back_channel_elements              4
 119                                 // num_lfe_channel_elements               2
 120                                 // num_assoc_data_elements                3
 121                                 // num_valid_cc_elements                  4
 122                                 // mono_mixdown_present                   1
 123                                 // mono_mixdown_element_number            4   if mono_mixdown_present == 1
 124                                 // stereo_mixdown_present                 1
 125                                 // stereo_mixdown_element_number          4   if stereo_mixdown_present == 1
 126                                 // matrix_mixdown_idx_present             1
 127                                 // matrix_mixdown_idx                     2   if matrix_mixdown_idx_present == 1
 128                                 // pseudo_surround_enable                 1   if matrix_mixdown_idx_present == 1
 129                                 // for (i = 0; i < num_front_channel_elements; i++) {
 130                                 //     front_element_is_cpe[i]            1
 131                                 //     front_element_tag_select[i]        4
 132                                 // }
 133                                 // for (i = 0; i < num_side_channel_elements; i++) {
 134                                 //     side_element_is_cpe[i]             1
 135                                 //     side_element_tag_select[i]         4
 136                                 // }
 137                                 // for (i = 0; i < num_back_channel_elements; i++) {
 138                                 //     back_element_is_cpe[i]             1
 139                                 //     back_element_tag_select[i]         4
 140                                 // }
 141                                 // for (i = 0; i < num_lfe_channel_elements; i++) {
 142                                 //     lfe_element_tag_select[i]          4
 143                                 // }
 144                                 // for (i = 0; i < num_assoc_data_elements; i++) {
 145                                 //     assoc_data_element_tag_select[i]   4
 146                                 // }
 147                                 // for (i = 0; i < num_valid_cc_elements; i++) {
 148                                 //     cc_element_is_ind_sw[i]            1
 149                                 //     valid_cc_element_tag_select[i]     4
 150                                 // }
 151                                 // byte_alignment()                       VAR
 152                                 // comment_field_bytes                    8
 153                                 // for (i = 0; i < comment_field_bytes; i++) {
 154                                 //     comment_field_data[i]              8
 155                                 // }
 156
 157                                 if (!$info['aac']['header']['is_vbr']) {
 158                                         $info['aac']['program_configs'][$i]['buffer_fullness']        = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
 159                                         $bitoffset += 20;
 160                                 }
 161                                 $info['aac']['program_configs'][$i]['element_instance_tag']       = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 162                                 $bitoffset += 4;
 163                                 $info['aac']['program_configs'][$i]['object_type']                = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
 164                                 $bitoffset += 2;
 165                                 $info['aac']['program_configs'][$i]['sampling_frequency_index']   = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 166                                 $bitoffset += 4;
 167                                 $info['aac']['program_configs'][$i]['num_front_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 168                                 $bitoffset += 4;
 169                                 $info['aac']['program_configs'][$i]['num_side_channel_elements']  = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 170                                 $bitoffset += 4;
 171                                 $info['aac']['program_configs'][$i]['num_back_channel_elements']  = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 172                                 $bitoffset += 4;
 173                                 $info['aac']['program_configs'][$i]['num_lfe_channel_elements']   = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
 174                                 $bitoffset += 2;
 175                                 $info['aac']['program_configs'][$i]['num_assoc_data_elements']    = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
 176                                 $bitoffset += 3;
 177                                 $info['aac']['program_configs'][$i]['num_valid_cc_elements']      = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 178                                 $bitoffset += 4;
 179                                 $info['aac']['program_configs'][$i]['mono_mixdown_present']       = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 180                                 $bitoffset += 1;
 181                                 if ($info['aac']['program_configs'][$i]['mono_mixdown_present']) {
 182                                         $info['aac']['program_configs'][$i]['mono_mixdown_element_number']    = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 183                                         $bitoffset += 4;
 184                                 }
 185                                 $info['aac']['program_configs'][$i]['stereo_mixdown_present']             = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 186                                 $bitoffset += 1;
 187                                 if ($info['aac']['program_configs'][$i]['stereo_mixdown_present']) {
 188                                         $info['aac']['program_configs'][$i]['stereo_mixdown_element_number']  = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 189                                         $bitoffset += 4;
 190                                 }
 191                                 $info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']         = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 192                                 $bitoffset += 1;
 193                                 if ($info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
 194                                         $info['aac']['program_configs'][$i]['matrix_mixdown_idx']             = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
 195                                         $bitoffset += 2;
 196                                         $info['aac']['program_configs'][$i]['pseudo_surround_enable']         = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 197                                         $bitoffset += 1;
 198                                 }
 199                                 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
 200                                         $info['aac']['program_configs'][$i]['front_element_is_cpe'][$j]     = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 201                                         $bitoffset += 1;
 202                                         $info['aac']['program_configs'][$i]['front_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 203                                         $bitoffset += 4;
 204                                 }
 205                                 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
 206                                         $info['aac']['program_configs'][$i]['side_element_is_cpe'][$j]     = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 207                                         $bitoffset += 1;
 208                                         $info['aac']['program_configs'][$i]['side_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 209                                         $bitoffset += 4;
 210                                 }
 211                                 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
 212                                         $info['aac']['program_configs'][$i]['back_element_is_cpe'][$j]     = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 213                                         $bitoffset += 1;
 214                                         $info['aac']['program_configs'][$i]['back_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 215                                         $bitoffset += 4;
 216                                 }
 217                                 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
 218                                         $info['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 219                                         $bitoffset += 4;
 220                                 }
 221                                 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
 222                                         $info['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 223                                         $bitoffset += 4;
 224                                 }
 225                                 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
 226                                         $info['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j]          = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
 227                                         $bitoffset += 1;
 228                                         $info['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j]   = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
 229                                         $bitoffset += 4;
 230                                 }
 231
 232                                 $bitoffset = ceil($bitoffset / 8) * 8;
 233
 234                                 $info['aac']['program_configs'][$i]['comment_field_bytes'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
 235                                 $bitoffset += 8;
 236                                 $info['aac']['program_configs'][$i]['comment_field']       = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $info['aac']['program_configs'][$i]['comment_field_bytes']));
 237                                 $bitoffset += 8 * $info['aac']['program_configs'][$i]['comment_field_bytes'];
 238
 239
 240                                 $info['aac']['header']['profile']                           = self::AACprofileLookup($info['aac']['program_configs'][$i]['object_type'], $info['aac']['header']['mpeg_version']);
 241                                 $info['aac']['program_configs'][$i]['sampling_frequency']   = self::AACsampleRateLookup($info['aac']['program_configs'][$i]['sampling_frequency_index']);
 242                                 $info['audio']['sample_rate']                               = $info['aac']['program_configs'][$i]['sampling_frequency'];
 243                                 $info['audio']['channels']                                  = self::AACchannelCountCalculate($info['aac']['program_configs'][$i]);
 244                                 if ($info['aac']['program_configs'][$i]['comment_field']) {
 245                                         $info['aac']['comments'][]                          = $info['aac']['program_configs'][$i]['comment_field'];
 246                                 }
 247                         }
 248                         $info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['audio']['bitrate'];
 249
 250                         $info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
 251
 252
 253
 254                         return true;
 255
 256                 } else {
 257
 258                         unset($info['fileformat']);
 259                         unset($info['aac']);
 260                         $this->error('AAC-ADIF synch not found at offset '.$info['avdataoffset'].' (expected "ADIF", found "'.substr($AACheader, 0, 4).'" instead)');
 261                         return false;
 262
 263                 }
 264
 265         }
 266
 267         /**
 268          * @param int  $MaxFramesToScan
 269          * @param bool $ReturnExtendedInfo
 270          *
 271          * @return bool
 272          */
 273         public function getAACADTSheaderFilepointer($MaxFramesToScan=1000000, $ReturnExtendedInfo=false) {
 274                 $info = &$this->getid3->info;
 275
 276                 // based loosely on code from AACfile by Jurgen Faul  <jfaulØgmx.de>
 277                 // http://jfaul.de/atl  or  http://j-faul.virtualave.net/atl/atl.html
 278
 279
 280                 // http://faac.sourceforge.net/wiki/index.php?page=ADTS // dead link
 281                 // http://wiki.multimedia.cx/index.php?title=ADTS
 282
 283                 // * ADTS Fixed Header: these don't change from frame to frame
 284                 // syncword                                       12    always: '111111111111'
 285                 // ID                                              1    0: MPEG-4, 1: MPEG-2
 286                 // MPEG layer                                      2    If you send AAC in MPEG-TS, set to 0
 287                 // protection_absent                               1    0: CRC present; 1: no CRC
 288                 // profile                                         2    0: AAC Main; 1: AAC LC (Low Complexity); 2: AAC SSR (Scalable Sample Rate); 3: AAC LTP (Long Term Prediction)
 289                 // sampling_frequency_index                        4    15 not allowed
 290                 // private_bit                                     1    usually 0
 291                 // channel_configuration                           3
 292                 // original/copy                                   1    0: original; 1: copy
 293                 // home                                            1    usually 0
 294                 // emphasis                                        2    only if ID == 0 (ie MPEG-4)  // not present in some documentation?
 295
 296                 // * ADTS Variable Header: these can change from frame to frame
 297                 // copyright_identification_bit                    1
 298                 // copyright_identification_start                  1
 299                 // aac_frame_length                               13    length of the frame including header (in bytes)
 300                 // adts_buffer_fullness                           11    0x7FF indicates VBR
 301                 // no_raw_data_blocks_in_frame                     2
 302
 303                 // * ADTS Error check
 304                 // crc_check                                      16    only if protection_absent == 0
 305
 306                 $byteoffset  = $info['avdataoffset'];
 307                 $framenumber = 0;
 308
 309                 // Init bit pattern array
 310                 static $decbin = array();
 311
 312                 // Populate $bindec
 313                 for ($i = 0; $i < 256; $i++) {
 314                         $decbin[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
 315                 }
 316
 317                 // used to calculate bitrate below
 318                 $BitrateCache = array();
 319
 320
 321                 while (true) {
 322                         // breaks out when end-of-file encountered, or invalid data found,
 323                         // or MaxFramesToScan frames have been scanned
 324
 325                         if (!getid3_lib::intValueSupported($byteoffset)) {
 326                                 $this->warning('Unable to parse AAC file beyond '.$this->ftell().' (PHP does not support file operations beyond '.round(PHP_INT_MAX / 1073741824).'GB)');
 327                                 return false;
 328                         }
 329                         $this->fseek($byteoffset);
 330
 331                         // First get substring
 332                         $substring = $this->fread(9); // header is 7 bytes (or 9 if CRC is present)
 333                         $substringlength = strlen($substring);
 334                         if ($substringlength != 9) {
 335                                 $this->error('Failed to read 7 bytes at offset '.($this->ftell() - $substringlength).' (only read '.$substringlength.' bytes)');
 336                                 return false;
 337                         }
 338                         // this would be easier with 64-bit math, but split it up to allow for 32-bit:
 339                         $header1 = getid3_lib::BigEndian2Int(substr($substring, 0, 2));
 340                         $header2 = getid3_lib::BigEndian2Int(substr($substring, 2, 4));
 341                         $header3 = getid3_lib::BigEndian2Int(substr($substring, 6, 1));
 342
 343                         $info['aac']['header']['raw']['syncword']          = ($header1 & 0xFFF0) >> 4;
 344                         if ($info['aac']['header']['raw']['syncword'] != 0x0FFF) {
 345                                 $this->error('Synch pattern (0x0FFF) not found at offset '.($this->ftell() - $substringlength).' (found 0x0'.strtoupper(dechex($info['aac']['header']['raw']['syncword'])).' instead)');
 346                                 //if ($info['fileformat'] == 'aac') {
 347                                 //      return true;
 348                                 //}
 349                                 unset($info['aac']);
 350                                 return false;
 351                         }
 352
 353                         // Gather info for first frame only - this takes time to do 1000 times!
 354                         if ($framenumber == 0) {
 355                                 $info['aac']['header_type']                      = 'ADTS';
 356                                 $info['fileformat']                              = 'aac';
 357                                 $info['audio']['dataformat']                     = 'aac';
 358
 359                                 $info['aac']['header']['raw']['mpeg_version']      = ($header1 & 0x0008) >> 3;
 360                                 $info['aac']['header']['raw']['mpeg_layer']        = ($header1 & 0x0006) >> 1;
 361                                 $info['aac']['header']['raw']['protection_absent'] = ($header1 & 0x0001) >> 0;
 362
 363                                 $info['aac']['header']['raw']['profile_code']      = ($header2 & 0xC0000000) >> 30;
 364                                 $info['aac']['header']['raw']['sample_rate_code']  = ($header2 & 0x3C000000) >> 26;
 365                                 $info['aac']['header']['raw']['private_stream']    = ($header2 & 0x02000000) >> 25;
 366                                 $info['aac']['header']['raw']['channels_code']     = ($header2 & 0x01C00000) >> 22;
 367                                 $info['aac']['header']['raw']['original']          = ($header2 & 0x00200000) >> 21;
 368                                 $info['aac']['header']['raw']['home']              = ($header2 & 0x00100000) >> 20;
 369                                 $info['aac']['header']['raw']['copyright_stream']  = ($header2 & 0x00080000) >> 19;
 370                                 $info['aac']['header']['raw']['copyright_start']   = ($header2 & 0x00040000) >> 18;
 371                                 $info['aac']['header']['raw']['frame_length']      = ($header2 & 0x0003FFE0) >>  5;
 372
 373                                 $info['aac']['header']['mpeg_version']     = ($info['aac']['header']['raw']['mpeg_version']      ? 2    : 4);
 374                                 $info['aac']['header']['crc_present']      = ($info['aac']['header']['raw']['protection_absent'] ? false: true);
 375                                 $info['aac']['header']['profile']          = self::AACprofileLookup($info['aac']['header']['raw']['profile_code'], $info['aac']['header']['mpeg_version']);
 376                                 $info['aac']['header']['sample_frequency'] = self::AACsampleRateLookup($info['aac']['header']['raw']['sample_rate_code']);
 377                                 $info['aac']['header']['private']          = (bool) $info['aac']['header']['raw']['private_stream'];
 378                                 $info['aac']['header']['original']         = (bool) $info['aac']['header']['raw']['original'];
 379                                 $info['aac']['header']['home']             = (bool) $info['aac']['header']['raw']['home'];
 380                                 $info['aac']['header']['channels']         = (($info['aac']['header']['raw']['channels_code'] == 7) ? 8 : $info['aac']['header']['raw']['channels_code']);
 381                                 if ($ReturnExtendedInfo) {
 382                                         $info['aac'][$framenumber]['copyright_id_bit']   = (bool) $info['aac']['header']['raw']['copyright_stream'];
 383                                         $info['aac'][$framenumber]['copyright_id_start'] = (bool) $info['aac']['header']['raw']['copyright_start'];
 384                                 }
 385
 386                                 if ($info['aac']['header']['raw']['mpeg_layer'] != 0) {
 387                                         $this->warning('Layer error - expected "0", found "'.$info['aac']['header']['raw']['mpeg_layer'].'" instead');
 388                                 }
 389                                 if ($info['aac']['header']['sample_frequency'] == 0) {
 390                                         $this->error('Corrupt AAC file: sample_frequency == zero');
 391                                         return false;
 392                                 }
 393
 394                                 $info['audio']['sample_rate'] = $info['aac']['header']['sample_frequency'];
 395                                 $info['audio']['channels']    = $info['aac']['header']['channels'];
 396                         }
 397
 398                         $FrameLength = ($header2 & 0x0003FFE0) >>  5;
 399
 400                         if (!isset($BitrateCache[$FrameLength])) {
 401                                 $BitrateCache[$FrameLength] = ($info['aac']['header']['sample_frequency'] / 1024) * $FrameLength * 8;
 402                         }
 403                         getid3_lib::safe_inc($info['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]], 1);
 404
 405                         $info['aac'][$framenumber]['aac_frame_length']     = $FrameLength;
 406
 407                         $info['aac'][$framenumber]['adts_buffer_fullness'] = (($header2 & 0x0000001F) << 6) & (($header3 & 0xFC) >> 2);
 408                         if ($info['aac'][$framenumber]['adts_buffer_fullness'] == 0x07FF) {
 409                                 $info['audio']['bitrate_mode'] = 'vbr';
 410                         } else {
 411                                 $info['audio']['bitrate_mode'] = 'cbr';
 412                         }
 413                         $info['aac'][$framenumber]['num_raw_data_blocks']  = (($header3 & 0x03) >> 0);
 414
 415                         if ($info['aac']['header']['crc_present']) {
 416                                 //$info['aac'][$framenumber]['crc'] = getid3_lib::BigEndian2Int(substr($substring, 7, 2);
 417                         }
 418
 419                         if (!$ReturnExtendedInfo) {
 420                                 unset($info['aac'][$framenumber]);
 421                         }
 422
 423                         /*
 424                         $rounded_precision = 5000;
 425                         $info['aac']['bitrate_distribution_rounded'] = array();
 426                         foreach ($info['aac']['bitrate_distribution'] as $bitrate => $count) {
 427                                 $rounded_bitrate = round($bitrate / $rounded_precision) * $rounded_precision;
 428                                 getid3_lib::safe_inc($info['aac']['bitrate_distribution_rounded'][$rounded_bitrate], $count);
 429                         }
 430                         ksort($info['aac']['bitrate_distribution_rounded']);
 431                         */
 432
 433                         $byteoffset += $FrameLength;
 434                         if ((++$framenumber < $MaxFramesToScan) && (($byteoffset + 10) < $info['avdataend'])) {
 435
 436                                 // keep scanning
 437
 438                         } else {
 439
 440                                 $info['aac']['frames']    = $framenumber;
 441                                 $info['playtime_seconds'] = ($info['avdataend'] / $byteoffset) * (($framenumber * 1024) / $info['aac']['header']['sample_frequency']);  // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
 442                                 if ($info['playtime_seconds'] == 0) {
 443                                         $this->error('Corrupt AAC file: playtime_seconds == zero');
 444                                         return false;
 445                                 }
 446                                 $info['audio']['bitrate']    = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
 447                                 ksort($info['aac']['bitrate_distribution']);
 448
 449                                 $info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
 450
 451                                 return true;
 452
 453                         }
 454                 }
 455                 // should never get here.
 456         }
 457
 458         /**
 459          * @param int $samplerateid
 460          *
 461          * @return int|string
 462          */
 463         public static function AACsampleRateLookup($samplerateid) {
 464                 static $AACsampleRateLookup = array();
 465                 if (empty($AACsampleRateLookup)) {
 466                         $AACsampleRateLookup[0]  = 96000;
 467                         $AACsampleRateLookup[1]  = 88200;
 468                         $AACsampleRateLookup[2]  = 64000;
 469                         $AACsampleRateLookup[3]  = 48000;
 470                         $AACsampleRateLookup[4]  = 44100;
 471                         $AACsampleRateLookup[5]  = 32000;
 472                         $AACsampleRateLookup[6]  = 24000;
 473                         $AACsampleRateLookup[7]  = 22050;
 474                         $AACsampleRateLookup[8]  = 16000;
 475                         $AACsampleRateLookup[9]  = 12000;
 476                         $AACsampleRateLookup[10] = 11025;
 477                         $AACsampleRateLookup[11] = 8000;
 478                         $AACsampleRateLookup[12] = 0;
 479                         $AACsampleRateLookup[13] = 0;
 480                         $AACsampleRateLookup[14] = 0;
 481                         $AACsampleRateLookup[15] = 0;
 482                 }
 483                 return (isset($AACsampleRateLookup[$samplerateid]) ? $AACsampleRateLookup[$samplerateid] : 'invalid');
 484         }
 485
 486         /**
 487          * @param int $profileid
 488          * @param int $mpegversion
 489          *
 490          * @return string
 491          */
 492         public static function AACprofileLookup($profileid, $mpegversion) {
 493                 static $AACprofileLookup = array();
 494                 if (empty($AACprofileLookup)) {
 495                         $AACprofileLookup[2][0]  = 'Main profile';
 496                         $AACprofileLookup[2][1]  = 'Low Complexity profile (LC)';
 497                         $AACprofileLookup[2][2]  = 'Scalable Sample Rate profile (SSR)';
 498                         $AACprofileLookup[2][3]  = '(reserved)';
 499                         $AACprofileLookup[4][0]  = 'AAC_MAIN';
 500                         $AACprofileLookup[4][1]  = 'AAC_LC';
 501                         $AACprofileLookup[4][2]  = 'AAC_SSR';
 502                         $AACprofileLookup[4][3]  = 'AAC_LTP';
 503                 }
 504                 return (isset($AACprofileLookup[$mpegversion][$profileid]) ? $AACprofileLookup[$mpegversion][$profileid] : 'invalid');
 505         }
 506
 507         /**
 508          * @param array $program_configs
 509          *
 510          * @return int
 511          */
 512         public static function AACchannelCountCalculate($program_configs) {
 513                 $channels = 0;
 514                 for ($i = 0; $i < $program_configs['num_front_channel_elements']; $i++) {
 515                         $channels++;
 516                         if ($program_configs['front_element_is_cpe'][$i]) {
 517                                 // each front element is channel pair (CPE = Channel Pair Element)
 518                                 $channels++;
 519                         }
 520                 }
 521                 for ($i = 0; $i < $program_configs['num_side_channel_elements']; $i++) {
 522                         $channels++;
 523                         if ($program_configs['side_element_is_cpe'][$i]) {
 524                                 // each side element is channel pair (CPE = Channel Pair Element)
 525                                 $channels++;
 526                         }
 527                 }
 528                 for ($i = 0; $i < $program_configs['num_back_channel_elements']; $i++) {
 529                         $channels++;
 530                         if ($program_configs['back_element_is_cpe'][$i]) {
 531                                 // each back element is channel pair (CPE = Channel Pair Element)
 532                                 $channels++;
 533                         }
 534                 }
 535                 for ($i = 0; $i < $program_configs['num_lfe_channel_elements']; $i++) {
 536                         $channels++;
 537                 }
 538                 return $channels;
 539         }
 540
 541 }