This page hosts a formal specification of ID3v2.4 tag for .mp3 files using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.
The JavaScript runtime library is available at npm:
npm install kaitai-structSee the usage examples in the JavaScript notes.
Parse structure from an ArrayBuffer:
var arrayBuffer = ...;
var data = new Id3v24(new KaitaiStream(arrayBuffer));
After that, one can get various attributes from the structure by accessing fields or properties like:
data.tag // => get tag
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
(function (root, factory) {
if (typeof define === 'function' && define.amd) {
define(['exports', 'kaitai-struct/KaitaiStream'], factory);
} else if (typeof exports === 'object' && exports !== null && typeof exports.nodeType !== 'number') {
factory(exports, require('kaitai-struct/KaitaiStream'));
} else {
factory(root.Id3v24 || (root.Id3v24 = {}), root.KaitaiStream);
}
})(typeof self !== 'undefined' ? self : this, function (Id3v24_, KaitaiStream) {
/**
* @see {@link http://id3.org/id3v2.4.0-structure|Source}
* @see {@link http://id3.org/id3v2.4.0-frames|Source}
*/
var Id3v24 = (function() {
function Id3v24(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root || this;
this._read();
}
Id3v24.prototype._read = function() {
this.tag = new Tag(this._io, this, this._root);
}
var Footer = Id3v24.Footer = (function() {
function Footer(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Footer.prototype._read = function() {
this.magic = this._io.readBytes(3);
if (!((KaitaiStream.byteArrayCompare(this.magic, new Uint8Array([51, 68, 73])) == 0))) {
throw new KaitaiStream.ValidationNotEqualError(new Uint8Array([51, 68, 73]), this.magic, this._io, "/types/footer/seq/0");
}
this.versionMajor = this._io.readU1();
this.versionRevision = this._io.readU1();
this.flags = new Flags(this._io, this, this._root);
this.size = new U4beSynchsafe(this._io, this, this._root);
}
var Flags = Footer.Flags = (function() {
function Flags(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Flags.prototype._read = function() {
this.flagUnsynchronization = this._io.readBitsIntBe(1) != 0;
this.flagHeaderex = this._io.readBitsIntBe(1) != 0;
this.flagExperimental = this._io.readBitsIntBe(1) != 0;
this.flagFooter = this._io.readBitsIntBe(1) != 0;
this.reserved = this._io.readBitsIntBe(4);
}
return Flags;
})();
return Footer;
})();
var Frame = Id3v24.Frame = (function() {
function Frame(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Frame.prototype._read = function() {
this.id = KaitaiStream.bytesToStr(this._io.readBytes(4), "ASCII");
this.size = new U4beSynchsafe(this._io, this, this._root);
this.flagsStatus = new FlagsStatus(this._io, this, this._root);
this.flagsFormat = new FlagsFormat(this._io, this, this._root);
this.data = this._io.readBytes(this.size.value);
}
var FlagsFormat = Frame.FlagsFormat = (function() {
function FlagsFormat(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
FlagsFormat.prototype._read = function() {
this.reserved1 = this._io.readBitsIntBe(1) != 0;
this.flagGrouping = this._io.readBitsIntBe(1) != 0;
this.reserved2 = this._io.readBitsIntBe(2);
this.flagCompressed = this._io.readBitsIntBe(1) != 0;
this.flagEncrypted = this._io.readBitsIntBe(1) != 0;
this.flagUnsynchronisated = this._io.readBitsIntBe(1) != 0;
this.flagIndicator = this._io.readBitsIntBe(1) != 0;
}
return FlagsFormat;
})();
var FlagsStatus = Frame.FlagsStatus = (function() {
function FlagsStatus(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
FlagsStatus.prototype._read = function() {
this.reserved1 = this._io.readBitsIntBe(1) != 0;
this.flagDiscardAlterTag = this._io.readBitsIntBe(1) != 0;
this.flagDiscardAlterFile = this._io.readBitsIntBe(1) != 0;
this.flagReadOnly = this._io.readBitsIntBe(1) != 0;
this.reserved2 = this._io.readBitsIntBe(4);
}
return FlagsStatus;
})();
Object.defineProperty(Frame.prototype, 'isInvalid', {
get: function() {
if (this._m_isInvalid !== undefined)
return this._m_isInvalid;
this._m_isInvalid = this.id == "\x00\x00\x00\x00";
return this._m_isInvalid;
}
});
return Frame;
})();
var Header = Id3v24.Header = (function() {
function Header(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Header.prototype._read = function() {
this.magic = this._io.readBytes(3);
if (!((KaitaiStream.byteArrayCompare(this.magic, new Uint8Array([73, 68, 51])) == 0))) {
throw new KaitaiStream.ValidationNotEqualError(new Uint8Array([73, 68, 51]), this.magic, this._io, "/types/header/seq/0");
}
this.versionMajor = this._io.readU1();
this.versionRevision = this._io.readU1();
this.flags = new Flags(this._io, this, this._root);
this.size = new U4beSynchsafe(this._io, this, this._root);
}
var Flags = Header.Flags = (function() {
function Flags(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Flags.prototype._read = function() {
this.flagUnsynchronization = this._io.readBitsIntBe(1) != 0;
this.flagHeaderex = this._io.readBitsIntBe(1) != 0;
this.flagExperimental = this._io.readBitsIntBe(1) != 0;
this.flagFooter = this._io.readBitsIntBe(1) != 0;
this.reserved = this._io.readBitsIntBe(4);
}
return Flags;
})();
return Header;
})();
var HeaderEx = Id3v24.HeaderEx = (function() {
function HeaderEx(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
HeaderEx.prototype._read = function() {
this.size = new U4beSynchsafe(this._io, this, this._root);
this.flagsEx = new FlagsEx(this._io, this, this._root);
this.data = this._io.readBytes(this.size.value - 5);
}
var FlagsEx = HeaderEx.FlagsEx = (function() {
function FlagsEx(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
FlagsEx.prototype._read = function() {
this.reserved1 = this._io.readBitsIntBe(1) != 0;
this.flagUpdate = this._io.readBitsIntBe(1) != 0;
this.flagCrc = this._io.readBitsIntBe(1) != 0;
this.flagRestrictions = this._io.readBitsIntBe(1) != 0;
this.reserved2 = this._io.readBitsIntBe(4);
}
return FlagsEx;
})();
return HeaderEx;
})();
var Padding = Id3v24.Padding = (function() {
function Padding(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Padding.prototype._read = function() {
this.padding = this._io.readBytes(this._root.tag.header.size.value - this._io.pos);
}
return Padding;
})();
var Tag = Id3v24.Tag = (function() {
function Tag(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
Tag.prototype._read = function() {
this.header = new Header(this._io, this, this._root);
if (this.header.flags.flagHeaderex) {
this.headerEx = new HeaderEx(this._io, this, this._root);
}
this.frames = [];
var i = 0;
do {
var _ = new Frame(this._io, this, this._root);
this.frames.push(_);
i++;
} while (!( ((this._io.pos + _.size.value > this.header.size.value) || (_.isInvalid)) ));
if (!(this.header.flags.flagFooter)) {
this.padding = new Padding(this._io, this, this._root);
}
if (this.header.flags.flagFooter) {
this.footer = new Footer(this._io, this, this._root);
}
}
return Tag;
})();
var U1beSynchsafe = Id3v24.U1beSynchsafe = (function() {
function U1beSynchsafe(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
U1beSynchsafe.prototype._read = function() {
this.padding = this._io.readBitsIntBe(1) != 0;
this.value = this._io.readBitsIntBe(7);
}
return U1beSynchsafe;
})();
var U2beSynchsafe = Id3v24.U2beSynchsafe = (function() {
function U2beSynchsafe(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
U2beSynchsafe.prototype._read = function() {
this.byte0 = new U1beSynchsafe(this._io, this, this._root);
this.byte1 = new U1beSynchsafe(this._io, this, this._root);
}
Object.defineProperty(U2beSynchsafe.prototype, 'value', {
get: function() {
if (this._m_value !== undefined)
return this._m_value;
this._m_value = this.byte0.value << 7 | this.byte1.value;
return this._m_value;
}
});
return U2beSynchsafe;
})();
var U4beSynchsafe = Id3v24.U4beSynchsafe = (function() {
function U4beSynchsafe(_io, _parent, _root) {
this._io = _io;
this._parent = _parent;
this._root = _root;
this._read();
}
U4beSynchsafe.prototype._read = function() {
this.short0 = new U2beSynchsafe(this._io, this, this._root);
this.short1 = new U2beSynchsafe(this._io, this, this._root);
}
Object.defineProperty(U4beSynchsafe.prototype, 'value', {
get: function() {
if (this._m_value !== undefined)
return this._m_value;
this._m_value = this.short0.value << 14 | this.short1.value;
return this._m_value;
}
});
return U4beSynchsafe;
})();
return Id3v24;
})();
Id3v24_.Id3v24 = Id3v24;
});