This page hosts a formal specification of ID3v2.3 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 C++98/STL generated by Kaitai Struct depends on the C++/STL runtime library. You have to install it before you can parse data.
For C++, the easiest way is to clone the runtime library sources and build them along with your project.
Using Kaitai Struct in C++/STL usually consists of 3 steps.
std::istream). One can open local file for that, or use existing std::string or char* buffer.
#include <fstream>
std::ifstream is("path/to/local/file.mp3", std::ifstream::binary);
#include <sstream>
std::istringstream is(str);
#include <sstream>
const char buf[] = { ... };
std::string str(buf, sizeof buf);
std::istringstream is(str);
#include "kaitai/kaitaistream.h"
kaitai::kstream ks(&is);
id3v2_3_t data(&ks);
After that, one can get various attributes from the structure by invoking getter methods like:
data.tag() // => get tag
#ifndef ID3V2_3_H_
#define ID3V2_3_H_
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
#include "kaitai/kaitaistruct.h"
#include <stdint.h>
#include <vector>
#if KAITAI_STRUCT_VERSION < 9000L
#error "Incompatible Kaitai Struct C++/STL API: version 0.9 or later is required"
#endif
/**
* \sa https://id3.org/id3v2.3.0 Source
*/
class id3v2_3_t : public kaitai::kstruct {
public:
class u1be_synchsafe_t;
class u2be_synchsafe_t;
class tag_t;
class u4be_synchsafe_t;
class frame_t;
class header_ex_t;
class header_t;
id3v2_3_t(kaitai::kstream* p__io, kaitai::kstruct* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~id3v2_3_t();
class u1be_synchsafe_t : public kaitai::kstruct {
public:
u1be_synchsafe_t(kaitai::kstream* p__io, id3v2_3_t::u2be_synchsafe_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~u1be_synchsafe_t();
private:
bool m_padding;
uint64_t m_value;
id3v2_3_t* m__root;
id3v2_3_t::u2be_synchsafe_t* m__parent;
public:
bool padding() const { return m_padding; }
uint64_t value() const { return m_value; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::u2be_synchsafe_t* _parent() const { return m__parent; }
};
class u2be_synchsafe_t : public kaitai::kstruct {
public:
u2be_synchsafe_t(kaitai::kstream* p__io, id3v2_3_t::u4be_synchsafe_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~u2be_synchsafe_t();
private:
bool f_value;
int32_t m_value;
public:
int32_t value();
private:
u1be_synchsafe_t* m_byte0;
u1be_synchsafe_t* m_byte1;
id3v2_3_t* m__root;
id3v2_3_t::u4be_synchsafe_t* m__parent;
public:
u1be_synchsafe_t* byte0() const { return m_byte0; }
u1be_synchsafe_t* byte1() const { return m_byte1; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::u4be_synchsafe_t* _parent() const { return m__parent; }
};
/**
* \sa Section 3. ID3v2 overview
*/
class tag_t : public kaitai::kstruct {
public:
tag_t(kaitai::kstream* p__io, id3v2_3_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~tag_t();
private:
header_t* m_header;
header_ex_t* m_header_ex;
bool n_header_ex;
public:
bool _is_null_header_ex() { header_ex(); return n_header_ex; };
private:
std::vector<frame_t*>* m_frames;
std::string m_padding;
bool n_padding;
public:
bool _is_null_padding() { padding(); return n_padding; };
private:
id3v2_3_t* m__root;
id3v2_3_t* m__parent;
public:
header_t* header() const { return m_header; }
header_ex_t* header_ex() const { return m_header_ex; }
std::vector<frame_t*>* frames() const { return m_frames; }
std::string padding() const { return m_padding; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t* _parent() const { return m__parent; }
};
class u4be_synchsafe_t : public kaitai::kstruct {
public:
u4be_synchsafe_t(kaitai::kstream* p__io, id3v2_3_t::header_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~u4be_synchsafe_t();
private:
bool f_value;
int32_t m_value;
public:
int32_t value();
private:
u2be_synchsafe_t* m_short0;
u2be_synchsafe_t* m_short1;
id3v2_3_t* m__root;
id3v2_3_t::header_t* m__parent;
public:
u2be_synchsafe_t* short0() const { return m_short0; }
u2be_synchsafe_t* short1() const { return m_short1; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::header_t* _parent() const { return m__parent; }
};
/**
* \sa Section 3.3. ID3v2 frame overview
*/
class frame_t : public kaitai::kstruct {
public:
class flags_t;
frame_t(kaitai::kstream* p__io, id3v2_3_t::tag_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~frame_t();
class flags_t : public kaitai::kstruct {
public:
flags_t(kaitai::kstream* p__io, id3v2_3_t::frame_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~flags_t();
private:
bool m_flag_discard_alter_tag;
bool m_flag_discard_alter_file;
bool m_flag_read_only;
uint64_t m_reserved1;
bool m_flag_compressed;
bool m_flag_encrypted;
bool m_flag_grouping;
uint64_t m_reserved2;
id3v2_3_t* m__root;
id3v2_3_t::frame_t* m__parent;
public:
bool flag_discard_alter_tag() const { return m_flag_discard_alter_tag; }
bool flag_discard_alter_file() const { return m_flag_discard_alter_file; }
bool flag_read_only() const { return m_flag_read_only; }
uint64_t reserved1() const { return m_reserved1; }
bool flag_compressed() const { return m_flag_compressed; }
bool flag_encrypted() const { return m_flag_encrypted; }
bool flag_grouping() const { return m_flag_grouping; }
uint64_t reserved2() const { return m_reserved2; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::frame_t* _parent() const { return m__parent; }
};
private:
bool f_is_invalid;
bool m_is_invalid;
public:
bool is_invalid();
private:
std::string m_id;
uint32_t m_size;
flags_t* m_flags;
std::string m_data;
id3v2_3_t* m__root;
id3v2_3_t::tag_t* m__parent;
public:
std::string id() const { return m_id; }
uint32_t size() const { return m_size; }
flags_t* flags() const { return m_flags; }
std::string data() const { return m_data; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::tag_t* _parent() const { return m__parent; }
};
/**
* ID3v2 extended header
* \sa Section 3.2. ID3v2 extended header
*/
class header_ex_t : public kaitai::kstruct {
public:
class flags_ex_t;
header_ex_t(kaitai::kstream* p__io, id3v2_3_t::tag_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~header_ex_t();
class flags_ex_t : public kaitai::kstruct {
public:
flags_ex_t(kaitai::kstream* p__io, id3v2_3_t::header_ex_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~flags_ex_t();
private:
bool m_flag_crc;
uint64_t m_reserved;
id3v2_3_t* m__root;
id3v2_3_t::header_ex_t* m__parent;
public:
bool flag_crc() const { return m_flag_crc; }
uint64_t reserved() const { return m_reserved; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::header_ex_t* _parent() const { return m__parent; }
};
private:
uint32_t m_size;
flags_ex_t* m_flags_ex;
uint32_t m_padding_size;
uint32_t m_crc;
bool n_crc;
public:
bool _is_null_crc() { crc(); return n_crc; };
private:
id3v2_3_t* m__root;
id3v2_3_t::tag_t* m__parent;
public:
uint32_t size() const { return m_size; }
flags_ex_t* flags_ex() const { return m_flags_ex; }
uint32_t padding_size() const { return m_padding_size; }
uint32_t crc() const { return m_crc; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::tag_t* _parent() const { return m__parent; }
};
/**
* ID3v2 fixed header
* \sa Section 3.1. ID3v2 header
*/
class header_t : public kaitai::kstruct {
public:
class flags_t;
header_t(kaitai::kstream* p__io, id3v2_3_t::tag_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~header_t();
class flags_t : public kaitai::kstruct {
public:
flags_t(kaitai::kstream* p__io, id3v2_3_t::header_t* p__parent = 0, id3v2_3_t* p__root = 0);
private:
void _read();
void _clean_up();
public:
~flags_t();
private:
bool m_flag_unsynchronization;
bool m_flag_headerex;
bool m_flag_experimental;
uint64_t m_reserved;
id3v2_3_t* m__root;
id3v2_3_t::header_t* m__parent;
public:
bool flag_unsynchronization() const { return m_flag_unsynchronization; }
bool flag_headerex() const { return m_flag_headerex; }
bool flag_experimental() const { return m_flag_experimental; }
uint64_t reserved() const { return m_reserved; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::header_t* _parent() const { return m__parent; }
};
private:
std::string m_magic;
uint8_t m_version_major;
uint8_t m_version_revision;
flags_t* m_flags;
u4be_synchsafe_t* m_size;
id3v2_3_t* m__root;
id3v2_3_t::tag_t* m__parent;
public:
std::string magic() const { return m_magic; }
uint8_t version_major() const { return m_version_major; }
uint8_t version_revision() const { return m_version_revision; }
flags_t* flags() const { return m_flags; }
u4be_synchsafe_t* size() const { return m_size; }
id3v2_3_t* _root() const { return m__root; }
id3v2_3_t::tag_t* _parent() const { return m__parent; }
};
private:
tag_t* m_tag;
id3v2_3_t* m__root;
kaitai::kstruct* m__parent;
public:
tag_t* tag() const { return m_tag; }
id3v2_3_t* _root() const { return m__root; }
kaitai::kstruct* _parent() const { return m__parent; }
};
#endif // ID3V2_3_H_
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
#include "id3v2_3.h"
#include "kaitai/exceptions.h"
id3v2_3_t::id3v2_3_t(kaitai::kstream* p__io, kaitai::kstruct* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = this;
m_tag = 0;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::_read() {
m_tag = new tag_t(m__io, this, m__root);
}
id3v2_3_t::~id3v2_3_t() {
_clean_up();
}
void id3v2_3_t::_clean_up() {
if (m_tag) {
delete m_tag; m_tag = 0;
}
}
id3v2_3_t::u1be_synchsafe_t::u1be_synchsafe_t(kaitai::kstream* p__io, id3v2_3_t::u2be_synchsafe_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::u1be_synchsafe_t::_read() {
m_padding = m__io->read_bits_int_be(1);
m_value = m__io->read_bits_int_be(7);
}
id3v2_3_t::u1be_synchsafe_t::~u1be_synchsafe_t() {
_clean_up();
}
void id3v2_3_t::u1be_synchsafe_t::_clean_up() {
}
id3v2_3_t::u2be_synchsafe_t::u2be_synchsafe_t(kaitai::kstream* p__io, id3v2_3_t::u4be_synchsafe_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
m_byte0 = 0;
m_byte1 = 0;
f_value = false;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::u2be_synchsafe_t::_read() {
m_byte0 = new u1be_synchsafe_t(m__io, this, m__root);
m_byte1 = new u1be_synchsafe_t(m__io, this, m__root);
}
id3v2_3_t::u2be_synchsafe_t::~u2be_synchsafe_t() {
_clean_up();
}
void id3v2_3_t::u2be_synchsafe_t::_clean_up() {
if (m_byte0) {
delete m_byte0; m_byte0 = 0;
}
if (m_byte1) {
delete m_byte1; m_byte1 = 0;
}
}
int32_t id3v2_3_t::u2be_synchsafe_t::value() {
if (f_value)
return m_value;
m_value = ((byte0()->value() << 7) | byte1()->value());
f_value = true;
return m_value;
}
id3v2_3_t::tag_t::tag_t(kaitai::kstream* p__io, id3v2_3_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
m_header = 0;
m_header_ex = 0;
m_frames = 0;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::tag_t::_read() {
m_header = new header_t(m__io, this, m__root);
n_header_ex = true;
if (header()->flags()->flag_headerex()) {
n_header_ex = false;
m_header_ex = new header_ex_t(m__io, this, m__root);
}
m_frames = new std::vector<frame_t*>();
{
int i = 0;
frame_t* _;
do {
_ = new frame_t(m__io, this, m__root);
m_frames->push_back(_);
i++;
} while (!( (((_io()->pos() + _->size()) > header()->size()->value()) || (_->is_invalid())) ));
}
n_padding = true;
if (header()->flags()->flag_headerex()) {
n_padding = false;
m_padding = m__io->read_bytes((header_ex()->padding_size() - _io()->pos()));
}
}
id3v2_3_t::tag_t::~tag_t() {
_clean_up();
}
void id3v2_3_t::tag_t::_clean_up() {
if (m_header) {
delete m_header; m_header = 0;
}
if (!n_header_ex) {
if (m_header_ex) {
delete m_header_ex; m_header_ex = 0;
}
}
if (m_frames) {
for (std::vector<frame_t*>::iterator it = m_frames->begin(); it != m_frames->end(); ++it) {
delete *it;
}
delete m_frames; m_frames = 0;
}
if (!n_padding) {
}
}
id3v2_3_t::u4be_synchsafe_t::u4be_synchsafe_t(kaitai::kstream* p__io, id3v2_3_t::header_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
m_short0 = 0;
m_short1 = 0;
f_value = false;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::u4be_synchsafe_t::_read() {
m_short0 = new u2be_synchsafe_t(m__io, this, m__root);
m_short1 = new u2be_synchsafe_t(m__io, this, m__root);
}
id3v2_3_t::u4be_synchsafe_t::~u4be_synchsafe_t() {
_clean_up();
}
void id3v2_3_t::u4be_synchsafe_t::_clean_up() {
if (m_short0) {
delete m_short0; m_short0 = 0;
}
if (m_short1) {
delete m_short1; m_short1 = 0;
}
}
int32_t id3v2_3_t::u4be_synchsafe_t::value() {
if (f_value)
return m_value;
m_value = ((short0()->value() << 14) | short1()->value());
f_value = true;
return m_value;
}
id3v2_3_t::frame_t::frame_t(kaitai::kstream* p__io, id3v2_3_t::tag_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
m_flags = 0;
f_is_invalid = false;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::frame_t::_read() {
m_id = kaitai::kstream::bytes_to_str(m__io->read_bytes(4), std::string("ASCII"));
m_size = m__io->read_u4be();
m_flags = new flags_t(m__io, this, m__root);
m_data = m__io->read_bytes(size());
}
id3v2_3_t::frame_t::~frame_t() {
_clean_up();
}
void id3v2_3_t::frame_t::_clean_up() {
if (m_flags) {
delete m_flags; m_flags = 0;
}
}
id3v2_3_t::frame_t::flags_t::flags_t(kaitai::kstream* p__io, id3v2_3_t::frame_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::frame_t::flags_t::_read() {
m_flag_discard_alter_tag = m__io->read_bits_int_be(1);
m_flag_discard_alter_file = m__io->read_bits_int_be(1);
m_flag_read_only = m__io->read_bits_int_be(1);
m_reserved1 = m__io->read_bits_int_be(5);
m_flag_compressed = m__io->read_bits_int_be(1);
m_flag_encrypted = m__io->read_bits_int_be(1);
m_flag_grouping = m__io->read_bits_int_be(1);
m_reserved2 = m__io->read_bits_int_be(5);
}
id3v2_3_t::frame_t::flags_t::~flags_t() {
_clean_up();
}
void id3v2_3_t::frame_t::flags_t::_clean_up() {
}
bool id3v2_3_t::frame_t::is_invalid() {
if (f_is_invalid)
return m_is_invalid;
m_is_invalid = id() == (std::string("\000\000\000\000", 4));
f_is_invalid = true;
return m_is_invalid;
}
id3v2_3_t::header_ex_t::header_ex_t(kaitai::kstream* p__io, id3v2_3_t::tag_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
m_flags_ex = 0;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::header_ex_t::_read() {
m_size = m__io->read_u4be();
m_flags_ex = new flags_ex_t(m__io, this, m__root);
m_padding_size = m__io->read_u4be();
n_crc = true;
if (flags_ex()->flag_crc()) {
n_crc = false;
m_crc = m__io->read_u4be();
}
}
id3v2_3_t::header_ex_t::~header_ex_t() {
_clean_up();
}
void id3v2_3_t::header_ex_t::_clean_up() {
if (m_flags_ex) {
delete m_flags_ex; m_flags_ex = 0;
}
if (!n_crc) {
}
}
id3v2_3_t::header_ex_t::flags_ex_t::flags_ex_t(kaitai::kstream* p__io, id3v2_3_t::header_ex_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::header_ex_t::flags_ex_t::_read() {
m_flag_crc = m__io->read_bits_int_be(1);
m_reserved = m__io->read_bits_int_be(15);
}
id3v2_3_t::header_ex_t::flags_ex_t::~flags_ex_t() {
_clean_up();
}
void id3v2_3_t::header_ex_t::flags_ex_t::_clean_up() {
}
id3v2_3_t::header_t::header_t(kaitai::kstream* p__io, id3v2_3_t::tag_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
m_flags = 0;
m_size = 0;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::header_t::_read() {
m_magic = m__io->read_bytes(3);
if (!(magic() == std::string("\x49\x44\x33", 3))) {
throw kaitai::validation_not_equal_error<std::string>(std::string("\x49\x44\x33", 3), magic(), _io(), std::string("/types/header/seq/0"));
}
m_version_major = m__io->read_u1();
m_version_revision = m__io->read_u1();
m_flags = new flags_t(m__io, this, m__root);
m_size = new u4be_synchsafe_t(m__io, this, m__root);
}
id3v2_3_t::header_t::~header_t() {
_clean_up();
}
void id3v2_3_t::header_t::_clean_up() {
if (m_flags) {
delete m_flags; m_flags = 0;
}
if (m_size) {
delete m_size; m_size = 0;
}
}
id3v2_3_t::header_t::flags_t::flags_t(kaitai::kstream* p__io, id3v2_3_t::header_t* p__parent, id3v2_3_t* p__root) : kaitai::kstruct(p__io) {
m__parent = p__parent;
m__root = p__root;
try {
_read();
} catch(...) {
_clean_up();
throw;
}
}
void id3v2_3_t::header_t::flags_t::_read() {
m_flag_unsynchronization = m__io->read_bits_int_be(1);
m_flag_headerex = m__io->read_bits_int_be(1);
m_flag_experimental = m__io->read_bits_int_be(1);
m_reserved = m__io->read_bits_int_be(5);
}
id3v2_3_t::header_t::flags_t::~flags_t() {
_clean_up();
}
void id3v2_3_t::header_t::flags_t::_clean_up() {
}