On iTunes and ID3 tagging


As is bloody usual, nothing seems to work exactly how you want it when you mix platforms. This time, while re-ripping an old album at blistering 320Kbps quality in iTunes to stuff my iPod with golden oldies I hadn't heard for a while, I idly clicked on one of the old 128Kbps MP3 files and (using MP3-Info on my XP box) clicked through the details and found it had a cover art image. Wierd. iTunes hadn't shown it.

Now ID3v2 APIC tags can have, according to the frame spec, 21 different meanings:

Picture type:  $00  Other
               $01  32x32 pixels 'file icon' (PNG only)
               $02  Other file icon
               $03  Cover (front)
               $04  Cover (back)
               $05  Leaflet page
               $06  Media (e.g. label side of CD)
               $07  Lead artist/lead performer/soloist
               $08  Artist/performer
               $09  Conductor
               $0A  Band/Orchestra
               $0B  Composer
               $0C  Lyricist/text writer
               $0D  Recording Location
               $0E  During recording
               $0F  During performance
               $10  Movie/video screen capture
               $11  A bright coloured fish
               $12  Illustration
               $13  Band/artist logotype
               $14  Publisher/Studio logotype

But iTunes, for whatever reason, only supports ID3v2.2, not 2.4, so I decide to dig around a bit to figure out if it used these mappings or older ones. I hop on over to Amazon, drop the album art on the freshly minted 320Kbps tracks, and copy one of them over to the XP box. Surprise, surprise. It has cover art, but on a different field than the 128Kbps one.

I go out and grab a couple of utilities (MP3 Image Extractor and MP3Rage) and confirm that yes, iTunes does tag MP3 files with artwork, but not in a fully compatible fashion (I have yet to dump the full ID3 tag to figure out exactly what is going on, but I have a lot of other stuff to do and someone must have figured this one out already).

It also doesn't seem to want to display artwork I add with either Windows utilities or with MP3Rage, which is a mild annoyance to me (I dig out the booklets more often to look at the lyrics than to remember what the cover looks like) but may well be an insurmountable difficulty for more perfectionist folk (and yes, there is such thing as an ID3 tag purist - the specimen I'm most acquainted with is probably preserving himself in vodka and tobacco even as I type this, basking in the combined wattage of his Stonehenge-like speakers while thinking of replacing the carpet due to it dulling the bass the teensiest bit...).

There is also a lot of (hexadecimal?) cruft in the "Comment" field that must be used internally in some fashion by iTunes, and that could probably have gone someplace else less conspicuous. It's plain silly to leave it visible.

But there's standards for you. Not even Apple can get everything right. If you have more detailed info on this, drop me a line (or a referrer). I'm a stickler for this sort of thing, and am considering cobbling up a Perl script to rehash all my APIC tags so that iTunes can display the artwork properly from the ID3 tag itself - if it can do it at all, of course.