  4.19  AENC Audio encryption
x 4.14  APIC Attached picture
  4.30  ASPI Audio seek point index (v2.4)

x 4.10  COMM Comments
  4.24  COMR Commercial frame

  4.25  ENCR Encryption method registration
  4.13  EQUA Equalization (v2.3)
  4.12  EQU2 Equalisation (v2.4)
  4.5   ETCO Event timing codes

  4.15  GEOB General encapsulated object
  4.26  GRID Group identification registration

* 4.4   IPLS Involved people list (v2.3)

  4.20  LINK Linked information

* 4.4   MCDI Music CD identifier
  4.6   MLLT MPEG location lookup table

  4.23  OWNE Ownership frame

  4.27  PRIV Private frame
  4.16  PCNT Play counter
  4.17  POPM Popularimeter
  4.21  POSS Position synchronisation frame

  4.18  RBUF Recommended buffer size
  4.11  RVA2 Relative volume adjustment (v2.4)
  4.12  RVAD Relative volume adjustment (v2.3)
  4.13  RVRB Reverb

  4.29  SEEK Seek frame (v2.4)
  4.28  SIGN Signature frame (v2.4)
  4.9   SYLT Synchronised lyric/text
  4.7   SYTC Synchronised tempo codes

x 4.2.1 TALB Album/Movie/Show title
  4.2.3 TBPM BPM (beats per minute)
x 4.2.2 TCOM Composer
x 4.2.3 TCON Content type
  4.2.4 TCOP Copyright message
  4.2.1 TDAT Date (v2.3)
  4.2.5 TDEN Encoding time (v2.4)
  4.2.5 TDLY Playlist delay
  4.2.5 TDOR Original release time (v2.4)
  4.2.5 TDRC Recording time (v2.4)
  4.2.5 TDRL Release time (v2.4)
  4.2.5 TDTG Tagging time (v2.4)
  4.2.2 TENC Encoded by
  4.2.2 TEXT Lyricist/Text writer
  4.2.3 TFLT File type (v2.4)
  4.2.2 TIPL Involved people list (v2.4)
x 4.2.1 TIT1 Content group description
x 4.2.1 TIT2 Title/songname/content description
x 4.2.1 TIT3 Subtitle/Description refinement
  4.2.3 TKEY Initial key
  4.2.3 TLAN Language(s)
  4.2.3 TLEN Length
  4.2.2 TMCL Musician credits list (v2.4)
  4.2.3 TMED Media type
  4.2.3 TMOO Mood (v2.4)
  4.2.1 TOAL Original album/movie/show title
  4.2.5 TOFN Original filename
  4.2.2 TOLY Original lyricist(s)/text writer(s)
  4.2.2 TOPE Original artist(s)/performer(s)
  4.2.1 TORY Original release year (v2.3)
  4.2.4 TOWN File owner/licensee
x 4.2.2 TPE1 Lead performer(s)/Soloist(s)
x 4.2.2 TPE2 Band/orchestra/accompaniment
x 4.2.2 TPE3 Conductor/performer refinement
x 4.2.2 TPE4 Interpreted, remixed, or otherwise modified by
  4.2.1 TPOS Part of a set
  4.2.4 TPRO Produced notice (v2.4)
  4.2.4 TPUB Publisher
x 4.2.1 TRCK Track number/Position in set
  4.2.1 TRDA Recording dates (v2.3)
  4.2.4 TRSN Internet radio station name
  4.2.4 TRSO Internet radio station owner
  4.2.5 TSOA Album sort order (v2.4)
  4.2.5 TSOP Performer sort order (v2.4)
  4.2.5 TSOT Title sort order (v2.4)
  4.2.1 TSRC ISRC (international standard recording code)
  4.2.5 TSSE Software/Hardware and settings used for encoding
  4.2.1 TSST Set subtitle (v2.4)
x 4.2.1 TYER Year (v2.3)
x 4.2.2 TXXX User defined text information frame

  4.1   UFID Unique file identifier
  4.22  USER Terms of use
  4.8   USLT Unsynchronised lyric/text transcription

x 4.3.1 WCOM Commercial information
x 4.3.1 WCOP Copyright/Legal information
x 4.3.1 WOAF Official audio file webpage
x 4.3.1 WOAR Official artist/performer webpage
x 4.3.1 WOAS Official audio source webpage
x 4.3.1 WORS Official Internet radio station homepage
x 4.3.1 WPAY Payment
x 4.3.1 WPUB Publishers official webpage
x 4.3.2 WXXX User defined URL link frame
