Metadata

SoundFile supports reading and writing string metadata tags on open handles. The tags follow libsndfile's SF_STR_* constants and are available on WAV, FLAC, AIFF, and other formats that support embedded metadata.

Reading Metadata

Call the named getter methods on a SoundFile instance opened in read mode:

$sf = new SoundFile('song.wav', FileMode::Read);

$title  = $sf->title();       // ?string
$artist = $sf->artist();      // ?string
$album  = $sf->album();       // ?string
$track  = $sf->trackNumber(); // ?string
$genre  = $sf->genre();       // ?string

$sf->close();

All getters return null if the tag is not present in the file.

Writing Metadata

Call the setter methods on a handle opened in write mode, then write your audio data:

$sf = new SoundFile('output.wav', FileMode::Write,
    sampleRate: 44100, channels: 2,
);

// Set metadata before writing
$sf->setTitle('My Song');
$sf->setArtist('My Band');
$sf->setAlbum('My Album');
$sf->setTrackNumber('3');

// Write the audio
$sf->write($audioData);
$sf->close();

// Re-open to verify
$sf2 = new SoundFile('output.wav', FileMode::Read);
echo $sf2->title(); // 'My Song'
$sf2->close();

TIP

Set metadata before writing the audio data. Some formats finalize the header on close, and metadata set after writing may not be persisted correctly.

Available Tags

Getter	Setter	Constant	Description
title()	setTitle()	0x01	Track title
copyright()	setCopyright()	0x02	Copyright notice
software()	setSoftware()	0x03	Encoder software
artist()	setArtist()	0x04	Artist name
comment()	setComment()	0x05	Free-text comment
date()	setDate()	0x06	Creation date
album()	setAlbum()	0x07	Album title
license()	setLicense()	0x08	License string
trackNumber()	setTrackNumber()	0x09	Track number
genre()	setGenre()	0x10	Genre name

Arbitrary Tags

For SF_STR constants not covered by the named methods, use getString() and setString():

$sf->setString(0x04, 'Custom Artist'); // Equivalent to setArtist()
$value = $sf->getString(0x04);         // Equivalent to artist()

Notes

• Not every container supports every metadata field.
• setString() will throw SoundFileException if called on a closed handle.
• Attempting to call a setter on a read-mode handle throws a SoundFileException