ID3 Tagging for Music Files - Recommended ID3v2 Tags For Songs

Written By: Constantine Roussos
9-26-2008
Categorized in: Best Practices & Tips, Digital Downloads & MP3, Technology

ID3v2 is a tagging system that lets you put enriching and relevant information about your audio files within them. In more down to earth terms, ID3v2 is a chunk of data prepended to the binary audio data. Each ID3v2 tag holds one or more smaller chunks of information, called frames. These frames can contain any kind of information and data you could think of such as title, album, performer, website, lyrics, equalizer presets, pictures etc.

ID3 is a very popular audio file data tagging format in active use by software and hardware developers around the world. ID3 tags are supported in software such as iTunes, Windows media Player, Winamp and hardware players like iPod, Creative Zem, Sony Walkman.

One of the design goals were that the ID3v2 should be very flexible and expandable. It is very easy to add new functions to the ID3v2 tag, because, just like in HTML, all parsers will ignore any information they don't recognize. Since each frame can be 16MB and the entire tag can be 256MB you'll probably never again be in the same situation as when you tried to write a useful comment in the old ID3 being limited to 30 characters.

Speaking of characters, the ID3v2 supports Unicode so even if you use the Bopomofo character set you'll be able to write in your native language. You can also include in which language you're writing so that one file might contain e.g. the same lyrics but in different languages.

Even though the tag supports a lot of byte consuming capabilities like inline pictures and even the possibility to include any other file, ID3v2 still tries to use the bytes as efficient as possibly. If you convert an ID3v1 tag to an ID3v2 tag it is even likely that the new tag will be smaller. If you convert an ID3v1 tag where all fields are full (that is, all 30 characters are used in every field) to an ID3v2 tag it will be 56 bytes bigger. This is the worst case scenario for ID3v1 to ID3v2 conversion.

Since it's so easy to implement new functionality into ID3v2, one can hope that we'll see a lot of creative uses for ID3v2 in the future. E.g. there is a built-in system for rating the music and counting how often you listen to a file, just to mention some brainstorm results that are included. This feature can be used to build playlists that play your favourite songs more often than others.

Some main features

The ID3v2 tag is a container format, just like IFF or PNG files, allowing new frames (chunks) as evolution proceeds.
Residing in the beginning of the audio file makes it suitable for streaming.
Has an 'unsynchronization scheme' to prevent ID3v2-incompatible players to attempt to play the tag.
Maximum tag size is 256 megabytes and maximum frame size is 16 megabytes.
Byte conservative and with the capability to compress data it keeps the files small.
The tag supports Unicode.
Isn't entirely focused on musical audio, but also other types of audio.
Has several new text fields such as composer, conductor, media type, BPM, copyright message, etc. and the possibility to design your own as you see fit.
Can contain lyrics as well as music-synced lyrics (karaoke) in almost any language.
Is able to contain volume, balance, equalizer and reverb settings.
Could be linked to CD-databases such as CCDB and FreeDB.
Is able to contain images and just about any file you want to include.
Supports enciphered information, linked information and weblinks.

The following frames are defined in ID3v2 informal standard. Users can define their own frames, if needed.

Text information frames

Almost all the capabilities from ID3 v1.1 are included in this class of frames. Each frame consists of a textstring describing most aspects of the music. The predefined frames are:

Album/Movie/Show title
BPM (beats per minute)
Composer
Content type
Copyright message
Date of recording
Playlist delay
Encoded by
Lyricist/Text writer
File type
Time of recording
Content group description
Title/songname/content description
Subtitle/Description refinement
Initial key
Language(s) used in the audio
Length
Media type of audio original
Original album/movie/show title
Original filename
Original lyricist(s)/text writer(s)
Original artist(s)/performer(s)
Original release year
File owner/licensee
Lead performer(s)/Soloist(s)
Band/orchestra/accompaniment
Conductor/performer refinement
Interpreted, remixed, or otherwise modified by
Part of a set
Publisher
Track number/Position in set
Recording dates
Internet radio station name
Internet radio station owner
Size
ISRC (international standard recording code)
Software/Hardware and settings used for encoding
Year of the recording
User defined text information frame

URL link frames

It is also possible to include various links to webpages and other on line resources. These are the predefined URL frames:

Commercial information
Copyright/Legal information
Official audio file webpage
Official artist/performer webpage
Official audio source webpage
Official internet radio station homepage
Payment
Publishers official webpage
User defined URL link frame

Involved people list
If you want to list everyone in the orchestra or all the technicians making the CD, this is the appropriate frame.
Comment
Still have something to say? Use this frame for general comments. This frame is the ID3v2 equivalence to the old comment field.
Unsynced lyric/text
Even though MP3 allows for very good technical quality, it could still be hard to hear all the words and lyrics, so a text/lyrics frame isn't completely useless.
Synced lyric/text
This frame is very similar to the unsynced lyric frame, but with one major difference. It has got timecodes encoded within the text, making it possible to synchronize lyrics and text to the song/speech. This could also be used to describe events that occur, e.g. if the sound is recorded from a movie.
Exact tempo codes
Having things move and flash to the beat of a piece of music is quite nice. To increase the accuracy of these kinds of applications, this frame constantly tells the present beat. It could even be used for very tempo-dramatic audio such as classical music.
Event timing codes
With this frame you can point out events like main themes, variations, key changes, outros etc. You can also use this frame to synchronize external events such as lights and special effects to the audio.
Unique MP3 identifier
With this frame you can assign the audiofile a reference to a database,
Music CD identifier
It would be nice to have a reference between your CD and your MP3, don't you think? It can be done by copying the TOC from the CD to this frame. You can also use this information to look up the CD in different databases.
Attached picture
With this frame you can include such pictures as the CD cover or the artist. It is also possible to attach an 'icon' for the file, potentially making your playlists more fun and readable.
General encapsulated object
To ensure that it will take a long time before ID3v2 is outdated we included the possibility to encapsulate any file you want, along with its filename and a MIME description.
Relative volume adjustment
Are you afraid of playing your audio files randomly at night because you know that some are sampled at higher volumes than others, making you jump five feet when one of those start playing? Use this frame to align the volumes of your audio files.
Equalization
Different rooms have different acoustics and need different equalizations. Different recordings are intended for different rooms and will therefore need individual equalization. This frame contains equalization for the audio. Can operate with +/- 65535 steps in frequencies 0 - 32767 Hz. It is very likely that equalization settings are valid for all the tracks on a CD, making the 'Music CD Identifier' useful.
Reverb settings
Music listening is very subjective. Different persons like different sounds, therefore we have the possibility to use different kinds of echoes on our amplifiers. Different songs do however need different kinds of reverb, hence this frame. It allows you to flexibly select how you want your sound to sound.
Play counter
With this frame you can count how many times a file has been played.
Popularimeter
How good do you think this file is? How often do you play it? The answers to these questions are stored in this frame, making possible new and exciting applications. For example, a player that plays files from your playlist differently frequently depending on how good you think they are.
Recommended buffer size
To enable ID3-tags embedded in contiguous, simplex MPEG streams such as radio the receiver has to know how much information to buffer so there will be no interference when a tag is transmitted.
Audio encryption
There are actually some people who wants to be paid for their work, and wants to distribute their work without having it uploaded to every MP3 FTP. With this flexible frame one can declare how and by who the audio is encrypted. There is of course possible to leave some parts of the music unencrypted as a teaser.

Linked information
It is really a waste of space if you have to place common information into every file. With this frame you can 'link' that info into the file.
MPEG location lookup table
This frame allows better precision when skipping forwards or backwards in the song

Position synchronisation frame
This frame may be used as ablsolute timestam in the MPEG stream. Useful for synchronizing things like text and events with multicasted music
Terms of use frame
This frame holds the terms of use for the music. Why not have shareware and freeware in music too?

Ownership frame
Holds information about the owner of the file.

Commercial frame
For advertising purposes

Encryption method registration
ID3v2 frames can be encrypted, but one must register the encryption method in this frame.

Group identification registration
It might also be handy to group several frames to a information entity that can be signed etc. With this frame such groupings can be registered.

Private frame
Vendor specific frame