getid3_dss Class Reference

getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g // More...

Inheritance diagram for getid3_dss:

Collaboration diagram for getid3_dss:

Public Member Functions
	Analyze ()
	DSSdateStringToUnixDate ($datestring)
	DSSsampleRateLookup ($sample_rate_index)
Public Member Functions inherited from getid3_handler
	__construct (getID3 $getid3, $call_module=null)
	Analyze ()
	AnalyzeString ($string)
	setStringMode ($string)
	saveAttachment ($name, $offset, $length, $image_mime=null)

Additional Inherited Members
Protected Member Functions inherited from getid3_handler
	ftell ()
	fread ($bytes)
	fseek ($bytes, $whence=SEEK_SET)
	feof ()
	isDependencyFor ($module)
	error ($text)
	warning ($text)
	notice ($text)
Protected Attributes inherited from getid3_handler
	$getid3
	$data_string_flag = false
	$data_string = ''
	$data_string_position = 0
	$data_string_length = 0

Detailed Description

getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //

Definition at line 18 of file module.audio.dss.php.

Member Function Documentation

Analyze()

getid3_dss::Analyze

(

)

Definition at line 21 of file module.audio.dss.php.

References $info, DSSdateStringToUnixDate(), DSSsampleRateLookup(), getid3_handler\fread(), getid3_handler\fseek(), getid3_lib\LittleEndian2Int(), and getid3_lib\PrintHexBytes().

                                  {
                $info = &$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;
        }

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DSSdateStringToUnixDate()

getid3_dss::DSSdateStringToUnixDate

(

$datestring

)

Definition at line 68 of file module.audio.dss.php.

References $d, $h, and $y.

Referenced by Analyze().

                                                             {
                $y = substr($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);
        }

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DSSsampleRateLookup()

getid3_dss::DSSsampleRateLookup

(

$sample_rate_index

)

Definition at line 79 of file module.audio.dss.php.

Referenced by Analyze().

                                                                {
                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];
        }

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The documentation for this class was generated from the following file:

• Services/MediaObjects/lib/getID3-1.9.10/getid3/module.audio.dss.php