Every time I hit the "Fill in tags using MusicBrainz" button, it changes to a disabled button reading "Generating audio fingerprint...", maxes out one CPU (KDE System Guard shows it's about 60/40 "user"/"sys"), and doesn't do anything. Is there something it's missing, something wrong with the tracks (I've tried two, both MP3), or what? It shouldn't take too long to process a 2.8 or 5.1 MB MP3...

You have to install the support first... in Ubuntu the package is called libtunepimp3... or something like that... but however with feisty i cant find the package anymore...

try the sollution if it is wrong post again...

edit: ok I found my mistake... the new package is called libtunepimp5 then it works again...

You were close. I needed the libtunepimp3-mp3 package.

However, now it's complaining that it can't connect to the TRM signature server.

enaut wrote:You have to install the support first... in Ubuntu the package is called libtunepimp3...

Nonetheless this should not happen, should it? Have you filed a bug report? It seems to me that is a quite untolerable behaviour. Amorak should give an error message when a package is missing and not just consuming CPU time.

libtunepimp3 was installed, while MP3 support for it was not. I'm guessing this was because of non-free software or something.
Yep, libtunepimp3 is in the Main repository, while libtunepimp3-mp3 is in the Universe one.
I'll file a bug report on it tomorrow.

Still, about not being able to reach the server...

EDIT: Bug reported, number 143890. Would've reported it earlier if it wasn't for loss of power.

Long as I'm here, thought I'd mention some extremely weird behavior Amarok just exhibited. For some reason, it decided to run a few copies of amarokapp a second, ending up with about one thousand (judging by PID numbering) before I killed them ("killall amarokapp" stopped it). I don't have any idea what caused it.

You can see the result it had on system resources here.