vendor/james-heinrich/getid3/getid3/module.audio.dss.php

   1 <?php
   2 /////////////////////////////////////////////////////////////////
   3 /// getID3() by James Heinrich <info@getid3.org>               //
   4 //  available at http://getid3.sourceforge.net                 //
   5 //            or http://www.getid3.org                         //
   6 //          also https://github.com/JamesHeinrich/getID3       //
   7 /////////////////////////////////////////////////////////////////
   8 // See readme.txt for more details                             //
   9 /////////////////////////////////////////////////////////////////
  10 //                                                             //
  11 // module.audio.dss.php                                        //
  12 // module for analyzing Digital Speech Standard (DSS) files    //
  13 // dependencies: NONE                                          //
  14 //                                                            ///
  15 /////////////////////////////////////////////////////////////////
  16
  17
  18 class getid3_dss extends getid3_handler
  19 {
  20
  21         public function Analyze() {
  22                 $info = &$this->getid3->info;
  23
  24                 $this->fseek($info['avdataoffset']);
  25                 $DSSheader  = $this->fread(1540);
  26
  27                 if (!preg_match('#^[\\x02-\\x06]ds[s2]#', $DSSheader)) {
  28                         $this->error('Expecting "[02-06] 64 73 [73|32]" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes(substr($DSSheader, 0, 4)).'"');
  29                         return false;
  30                 }
  31
  32                 // some structure information taken from http://cpansearch.perl.org/src/RGIBSON/Audio-DSS-0.02/lib/Audio/DSS.pm
  33                 $info['encoding']              = 'ISO-8859-1'; // not certain, but assumed
  34                 $info['dss'] = array();
  35
  36                 $info['fileformat']            = 'dss';
  37                 $info['mime_type']             = 'audio/x-'.substr($DSSheader, 1, 3); // "audio/x-dss" or "audio/x-ds2"
  38                 $info['audio']['dataformat']   =            substr($DSSheader, 1, 3); //         "dss" or         "ds2"
  39                 $info['audio']['bitrate_mode'] = 'cbr';
  40
  41                 $info['dss']['version']            =                            ord(substr($DSSheader,    0,   1));
  42                 $info['dss']['hardware']           =                           trim(substr($DSSheader,   12,  16)); // identification string for hardware used to create the file, e.g. "DPM 9600", "DS2400"
  43                 $info['dss']['unknown1']           =   getid3_lib::LittleEndian2Int(substr($DSSheader,   28,   4));
  44                 // 32-37 = "FE FF FE FF F7 FF" in all the sample files I've seen
  45                 $info['dss']['date_create_unix']   = $this->DSSdateStringToUnixDate(substr($DSSheader,   38,  12));
  46                 $info['dss']['date_complete_unix'] = $this->DSSdateStringToUnixDate(substr($DSSheader,   50,  12));
  47                 $info['dss']['playtime_sec']       = intval((substr($DSSheader,  62, 2) * 3600) + (substr($DSSheader,  64, 2) * 60) + substr($DSSheader,  66, 2)); // approximate file playtime in HHMMSS
  48                 if ($info['dss']['version'] <= 3) {
  49                         $info['dss']['playtime_ms']        =   getid3_lib::LittleEndian2Int(substr($DSSheader,  512,   4)); // exact file playtime in milliseconds. Has also been observed at offset 530 in one sample file, with something else (unknown) at offset 512
  50                         $info['dss']['priority']           =                            ord(substr($DSSheader,  793,   1));
  51                         $info['dss']['comments']           =                           trim(substr($DSSheader,  798, 100));
  52                         $info['dss']['sample_rate_index']  =                            ord(substr($DSSheader, 1538,   1));  // this isn't certain, this may or may not be where the sample rate info is stored, but it seems consistent on my small selection of sample files
  53                         $info['audio']['sample_rate']      = $this->DSSsampleRateLookup($info['dss']['sample_rate_index']);
  54                 } else {
  55                         $this->getid3->warning('DSS above version 3 not fully supported in this version of getID3. Any additional documentation or format specifications would be welcome. This file is version '.$info['dss']['version']);
  56                 }
  57
  58                 $info['audio']['bits_per_sample']  = 16; // maybe, maybe not -- most compressed audio formats don't have a fixed bits-per-sample value, but this is a reasonable approximation
  59                 $info['audio']['channels']         = 1;
  60
  61                 if (!empty($info['dss']['playtime_ms']) && (floor($info['dss']['playtime_ms'] / 1000) == $info['dss']['playtime_sec'])) { // *should* just be playtime_ms / 1000 but at least one sample file has playtime_ms at offset 530 instead of offset 512, so safety check
  62                         $info['playtime_seconds'] = $info['dss']['playtime_ms'] / 1000;
  63                 } else {
  64                         $info['playtime_seconds'] = $info['dss']['playtime_sec'];
  65                         if (!empty($info['dss']['playtime_ms'])) {
  66                                 $this->getid3->warning('playtime_ms ('.number_format($info['dss']['playtime_ms'] / 1000, 3).') does not match playtime_sec ('.number_format($info['dss']['playtime_sec']).') - using playtime_sec value');
  67                         }
  68                 }
  69                 $info['audio']['bitrate'] = ($info['filesize'] * 8) / $info['playtime_seconds'];
  70
  71                 return true;
  72         }
  73
  74         public function DSSdateStringToUnixDate($datestring) {
  75                 $y = substr($datestring,  0, 2);
  76                 $m = substr($datestring,  2, 2);
  77                 $d = substr($datestring,  4, 2);
  78                 $h = substr($datestring,  6, 2);
  79                 $i = substr($datestring,  8, 2);
  80                 $s = substr($datestring, 10, 2);
  81                 $y += (($y < 95) ? 2000 : 1900);
  82                 return mktime($h, $i, $s, $m, $d, $y);
  83         }
  84
  85         public function DSSsampleRateLookup($sample_rate_index) {
  86                 static $dssSampleRateLookup = array(
  87                         0x0A => 16000,
  88                         0x0C => 11025,
  89                         0x0D => 12000,
  90                         0x15 =>  8000,
  91                 );
  92                 if (!array_key_exists($sample_rate_index, $dssSampleRateLookup)) {
  93                         $this->getid3->warning('unknown sample_rate_index: 0x'.strtoupper(dechex($sample_rate_index)));
  94                         return false;
  95                 }
  96                 return $dssSampleRateLookup[$sample_rate_index];
  97         }
  98
  99 }