APE key

An APE tag item key is a key for accessing special meta-information in an audio file.

APE tag item keys can have a length of 2 (including) up to 255 (including) characters in the range from 0x20 (Space) until 0x7E (Tilde).

Typical keys should have a length of 2 ... 16 characters using the following characters:
Space (0x20), Slash (0x2F), Digits (0x30...0x39), Letters (0x41...0x5A, 0x61...0x7A).

Values can contain binary data, a value or a list of values. See here.
List of values can be mixed, i.e. contain UTF-8 strings and external references
beginning with file://..., http://www..., ftp://ftp....

Not allowed are the following keys: ID3, TAG, OggS and MP+.

Currently the following keys are defined:

Key	Meaning	Recommended format of value
Title	Music Piece Title Music Work	UTF-8 string
Subtitle	Title when TITLE contains the work or additional sub title	UTF-8 string
Artist	Performing artist List of Performing Artists	UTF-8 string List of UTF-8 strings
Album	Album name	UTF-8 string
Debut album	Debut album name	UTF-8 string
Publisher	Record label or publisher	UTF-8 string
Conductor	Conductor	UTF-8 string
Track	Track Number Track Number/Total Tracks Number	Integer Integer/Integer
Composer	Name of the original composer Name of the original arranger	UTF-8 string List of UTF-8 strings
Comment	User comment(s)	UTF-8 string List of UTF-8 strings Link List of Links
Copyright	Copyright holder	UTF-8 string List of UTF-8 strings