ID3 Functions

Introduction

These functions let you read and manipulate ID3 tags. ID3 tags are used in MP3 files to store title of the song, as well as information about the artist, album, genre, year and track number.

Since version 0.2 it is also possible to extract text frames from ID3 v2.2+ tags.

Requirements

No external libraries are needed to build this extension.

Installation

id3 is part of PECL and can be installed using the PEAR installer. To compile PHP with id3 support, download the sourcecode, put it in php-src/ext/id3 and compile PHP using --enable-id3.

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

This extension has no resource types defined.

Predefined Constants

Most of the id3 functions either let you specify or return a tag version. In order to specify the version please use on of these constants.

ID3_V1_0 (integer): ID3_V1_0 is used if you are working with ID3 V1.0 tags. These tags may contain the fields title, artist, album, genre, year and comment.
ID3_V1_1 (integer): ID3_V1_1 is used if you are working with ID3 V1.1 tags. These tags may all information contained in v1.0 tags plus the track number.
ID3_V2_1 (integer): ID3_V2_1 is used if you are working with ID3 V2.1 tags.
ID3_V2_2 (integer): ID3_V2_2 is used if you are working with ID3 V2.2 tags.
ID3_V2_3 (integer): ID3_V2_3 is used if you are working with ID3 V2.3 tags.
ID3_V2_4 (integer): ID3_V2_4 is used if you are working with ID3 V2.4 tags.
ID3_BEST (integer): ID3_BEST is used if would like to let the id3 functions determine which tag version should be used.

Table of Contents

id3_get_frame_long_name — Get the long name of an ID3v2 frame
id3_get_frame_short_name — Get the short name of an ID3v2 frame
id3_get_genre_id — Get the id for a genre
id3_get_genre_list — Get all possible genre values
id3_get_genre_name — Get the name for a genre id
id3_get_tag — Get all information stored in an ID3 tag
id3_get_version — Get version of an ID3 tag
id3_remove_tag — Remove an existing ID3 tag
id3_set_tag — Update information stored in an ID3 tag

Code Examples / Notes » ref.id3

Windows XP users may be having trouble with routines provided here and may (as above) only have access to "read" classes. The following very simplified "write" can be used for replacing Windows Media Player file tags, and with care and adjustments, can be used more generally. define(_Title,"TIT2"); define(_Artist,"TPE1"); define(_Group,"TPE2"); define(_Album,"TALB"); define(_Genre,"TCON"); define(_TrackNo,"TRCK"); define(_Year,"TYER"); $frames = array(_Album=>"The Ultimate Experience", _TrackNo=>"1", _Title=>"All along the watchtower", _Artist=>"Jimi Hendrix", _Group=>"", _Year=>"19xx", _Genre=>"Rock"); #.......................................... # WRITE ID3 TAGS (Write MP3 [v1, v2] #.......................................... function writeTags($mp3) { $fl = file_get_contents($mp3); $Header = substr($fl,0,10); $tagLen = calcDecTagLen(substr($Header,6,4),$tagLen); $music = substr($fl,$tagLen+10,-128); # Can use input Header for output but you may # wish to change the output filename for testing file_put_contents($mp3,mkV2Tag($Header,$tagLen).$music.mkV1Tag()); } # Create the V2 tag function mkV2Tag($Hdr,$tagLen) { Global $frames; $null = chr(0); $nl3 = $null.$null.$null; # 0 bytes for flags and encoding $out = ""; foreach($frames as $ky=>$val) { $n=strlen($val)+1; $out.= $ky.mkFrmLen($n).$nl3.$val; } return $Hdr.str_pad($out,$tagLen,$null); } # Calculate Tag Length from bytes 6-10 of existing header function calcDecTagLen($word) { $m = 1; $int = 0; for ($i=strlen($word)-1;$i>-1;$i--) { $int +=$m*ord($word[$i]); $m=$m*128; } return $int; } # Make the 4 byte frame length value for the V2tag function mkFrmLen($int) { $hx = ""; while ($int>0) { $n = $int % 256; $hx = chr($n).$hx; $int=floor($int/256); } return str_pad($hx,4,chr(0),STR_PAD_LEFT); } # Create the 128 byte V1 tag function mkV1Tag() { Global $frames; $tagOut = "TAG". adj($frames[_Title]). adj($frames[_Artist]). adj($frames[_Album]). str_pad($frames[_Year],4). str_pad(" ",29," "). chr($frames[_TrackNo]). chr($n); return $tagOut; } # Pad the header to 30 characters function adj($str) { return substr(str_pad($str,30,chr(0)),0,30); } # This is a simple example for an mp3 in current folder writeTags("01-Cognac Blues.mp3");

Oops! The code below was inelegant to begin with and stripped down further to limit space taken up here, contains one serious bug: the assumption that the input tag header (first 10 bytes) will do for output. This likely works fine if your own finely tuned tags take up less real estate than MS's bloated headers but not if you read mp3s from a product that sets a tag length less than the length of your own header! A simple fix for this is to insert the code: $tagLen = 1024; # or whatever you like >your actual $Header = substr($Header,0,6).setHexTagLen($tagLen); after the line '$music = etc. The setHexTagLen can be figured out from the calcDecTagLen but here's some sample code. function setHexTagLen($int) { $n = pow(128,3); $intVar = $int; $m = ""; for ($i=0;$i<4;$i++) { $m .= chr(floor($intVar/$n)); $intVar = $intVar % $n; $n=$n/128; } return $m; }