Pony.fm/app/Library/getid3-new/getid3/module.audio.dss.php

93 lines
5 KiB
PHP
Executable file

<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org> //
// available at http://getid3.sourceforge.net //
// or http://www.getid3.org //
// also https://github.com/JamesHeinrich/getID3 //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details //
/////////////////////////////////////////////////////////////////
// //
// module.audio.dss.php //
// module for analyzing Digital Speech Standard (DSS) files //
// dependencies: NONE //
// ///
/////////////////////////////////////////////////////////////////
class getid3_dss extends getid3_handler
{
public function Analyze() {
$info = &$this->getid3->info;
$this->fseek($info['avdataoffset']);
$DSSheader = $this->fread(1540);
if (!preg_match('#^(\x02|\x03)ds[s2]#', $DSSheader)) {
$info['error'][] = 'Expecting "[02-03] 64 73 [73|32]" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes(substr($DSSheader, 0, 4)).'"';
return false;
}
// some structure information taken from http://cpansearch.perl.org/src/RGIBSON/Audio-DSS-0.02/lib/Audio/DSS.pm
$info['encoding'] = 'ISO-8859-1'; // not certain, but assumed
$info['dss'] = array();
$info['fileformat'] = 'dss';
$info['mime_type'] = 'audio/x-'.substr($DSSheader, 1, 3); // "audio/x-dss" or "audio/x-ds2"
$info['audio']['dataformat'] = substr($DSSheader, 1, 3); // "dss" or "ds2"
$info['audio']['bitrate_mode'] = 'cbr';
$info['dss']['version'] = ord(substr($DSSheader, 0, 1));
$info['dss']['hardware'] = trim(substr($DSSheader, 12, 16)); // identification string for hardware used to create the file, e.g. "DPM 9600", "DS2400"
$info['dss']['unknown1'] = getid3_lib::LittleEndian2Int(substr($DSSheader, 28, 4));
// 32-37 = "FE FF FE FF F7 FF" in all the sample files I've seen
$info['dss']['date_create'] = $this->DSSdateStringToUnixDate(substr($DSSheader, 38, 12));
$info['dss']['date_complete'] = $this->DSSdateStringToUnixDate(substr($DSSheader, 50, 12));
$info['dss']['playtime_sec'] = intval((substr($DSSheader, 62, 2) * 3600) + (substr($DSSheader, 64, 2) * 60) + substr($DSSheader, 66, 2)); // approximate file playtime in HHMMSS
$info['dss']['playtime_ms'] = getid3_lib::LittleEndian2Int(substr($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
$info['dss']['priority'] = ord(substr($DSSheader, 793, 1));
$info['dss']['comments'] = trim(substr($DSSheader, 798, 100));
$info['dss']['sample_rate_index'] = ord(substr($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
$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
$info['audio']['sample_rate'] = $this->DSSsampleRateLookup($info['dss']['sample_rate_index']);
$info['audio']['channels'] = 1;
$info['playtime_seconds'] = $info['dss']['playtime_ms'] / 1000;
if (floor($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
$info['playtime_seconds'] = $info['dss']['playtime_sec'];
$this->getid3->warning('playtime_ms ('.number_format($info['dss']['playtime_ms'] / 1000, 3).') does not match playtime_sec ('.number_format($info['dss']['playtime_sec']).') - using playtime_sec value');
}
$info['audio']['bitrate'] = ($info['filesize'] * 8) / $info['playtime_seconds'];
return true;
}
public function DSSdateStringToUnixDate($datestring) {
$y = substr($datestring, 0, 2);
$m = substr($datestring, 2, 2);
$d = substr($datestring, 4, 2);
$h = substr($datestring, 6, 2);
$i = substr($datestring, 8, 2);
$s = substr($datestring, 10, 2);
$y += (($y < 95) ? 2000 : 1900);
return mktime($h, $i, $s, $m, $d, $y);
}
public function DSSsampleRateLookup($sample_rate_index) {
static $dssSampleRateLookup = array(
0x0A => 16000,
0x0C => 11025,
0x0D => 12000,
0x15 => 8000,
);
if (!array_key_exists($sample_rate_index, $dssSampleRateLookup)) {
$this->getid3->warning('unknown sample_rate_index: '.$sample_rate_index);
return false;
}
return $dssSampleRateLookup[$sample_rate_index];
}
}