Well, the next release will have much improved playtime calculation.
Basic ID3v2-support has been added (see list below) including attached images and unsychronized lyrics.
APIC [#sec4.15 Attached picture]
COMM [#sec4.11 Comments]
TALB [#TALB Album/Movie/Show title]
TCOM [#TCOM Composer]
TCON [#TCON Content type]
TCOP [#TCOP Copyright message]
TIT2 [#TIT2 Title/songname/content description]
TOPE [#TOPE Original artist(s)/performer(s)]
TPE1 [#TPE1 Lead performer(s)/Soloist(s)]
TPE2 [#TPE2 Band/orchestra/accompaniment]
TPOS [#TPOS Part of a set]
TPUB [#TPUB Publisher]
TRCK [#TRCK Track number/Position in set]
TSSE [#TSEE Software/Hardware and settings used for encoding]
TYER [#TYER Year]
USLT [#sec4.9 Unsychronized lyric/text transcription]
ID3v2.3 has a plethora of possible content frames. Many will probably seldom be used.
I just wonder which of the remaining might be of general interest:
AENC [#sec4.20 Audio encryption]
COMR [#sec4.25 Commercial frame]
ENCR [#sec4.26 Encryption method registration]
EQUA [#sec4.13 Equalization]
ETCO [#sec4.6 Event timing codes]
GEOB [#sec4.16 General encapsulated object]
GRID [#sec4.27 Group identification registration]
IPLS [#sec4.4 Involved people list]
LINK [#sec4.21 Linked information]
MCDI [#sec4.5 Music CD identifier]
MLLT [#sec4.7 MPEG location lookup table]
OWNE [#sec4.24 Ownership frame]
PRIV [#sec4.28 Private frame]
PCNT [#sec4.17 Play counter]
POPM [#sec4.18 Popularimeter]
POSS [#sec4.22 Position synchronisation frame]
RBUF [#sec4.19 Recommended buffer size]
RVAD [#sec4.12 Relative volume adjustment]
RVRB [#sec4.14 Reverb]
SYLT [#sec4.10 Synchronized lyric/text]
SYTC [#sec4.8 Synchronized tempo codes]
TBPM [#TBPM BPM (beats per minute)]
TDAT [#TDAT Date]
TDLY [#TDLY Playlist delay]
TENC [#TENC Encoded by]
TEXT [#TEXT Lyricist/Text writer]
TFLT [#TFLT File type]
TIME [#TIME Time]
TIT1 [#TIT1 Content group description]
TIT3 [#TIT3 Subtitle/Description refinement]
TKEY [#TKEY Initial key]
TLAN [#TLAN Language(s)]
TLEN [#TLEN Length]
TMED [#TMED Media type]
TOAL [#TOAL Original album/movie/show title]
TOFN [#TOFN Original filename]
TOLY [#TOLY Original lyricist(s)/text writer(s)]
TORY [#TORY Original release year]
TOWN [#TOWN File owner/licensee]
TPE3 [#TPE3 Conductor/performer refinement]
TPE4 [#TPE4 Interpreted, remixed, or otherwise modified by]
TRDA [#TRDA Recording dates]
TRSN [#TRSN Internet radio station name]
TRSO [#TRSO Internet radio station owner]
TSIZ [#TSIZ Size]
TSRC [#TSRC ISRC (international standard recording code)]
TXXX [#TXXX User defined text information frame]
UFID [#sec4.1 Unique file identifier]
USER [#sec4.23 Terms of use]
WCOM [#WCOM Commercial information]
WCOP [#WCOP Copyright/Legal information]
WOAF [#WOAF Official audio file webpage]
WOAR [#WOAR Official artist/performer webpage]
WOAS [#WOAS Official audio source webpage]
WORS [#WORS Official internet radio station homepage]
WPAY [#WPAY Payment]
WPUB [#WPUB Publishers official webpage]
WXXX [#WXXX User defined URL link frame]
To be able to dynamically display images embedded in mp3s I had to turn the plugin into a module.