I am noticing some unusual tags being written when I edit a tag with Amarok.  I'm using Amarok  1.4.7.  I noticed this when I extracted the tags with extract(libextractor).  Here is the scenario

1) When I modify a tag using amarok there is extra tag information as seen by extractor and strings
2) Standard mp3 tools to extract tags do not seem to see this information.
3) I have no ability to edit/remove this information since other tools cannot see it
4) If I edit an mp3 with other tools, that have not been previously edited by amarok, I do not see this information.


Though this does not seem to directly hinder anything, I would like to know what this information is, if it has a purpose, if I can prevent amarok from putting it in, or if it is a bug. 

Thanks for the help.

Please review the command output below for details:

extract Output - There is a "T" appended to each "extra" tag:
teramac Paul Van Dyk - Nothing But You # extract 01-Nothing_But_You_PVD_Radio_Mix_.mp3
format - 192 kbps, 44100 hz, 3m35 stereo
resource-type - MPEG V1
mimetype - audio/mpeg
description - Paul Van Dyk: Nothing But You [PVD Radio Mix (Nothing But You)
comment -
genre - Trance
date - 2003
album - Nothing But You
artist - Paul Van Dyk
title - Nothing But You [PVD Radio Mix
genre - 31
date - 2003T
album - Nothing But YouT
artist - Paul Van DykT
title - Nothing But You [PVD Radio MixT

mp3info Output - Normal, no issue:
File: 01-Nothing_But_You_PVD_Radio_Mix_.mp3
Title:  Nothing But You [PVD Radio Mix Track: 1
Artist:  Paul Van Dyk
Album:  Nothing But You                Year:  2003
Comment:                                Genre: Trance [31]

strings Output - raw text inside the mp3 file, I just grep'd for PVD, so the other affected tags are not shown:
Nothing But You [PVD Radio MixTPE1
UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUULAME3.93UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUTAGNothing But You [PVD Radio MixPaul Van Dyk

FYI,

Looking at this a little more, I believe this to be an error with the way amarok is writing id3v2 tags.  It appears it is writing both id3v1&2 tags, but the v2 tags are not being written correctly.  For instance, if I use id3v2 to display v2 tags, nothing but v1 information is displayed.  If I do a -d flag to wipe the v2 tags, it does wipe them and the odd "duplicates" are removed as seen from my extract output. 

So, if i'm on the right track, is there a way I can diagnose why/if id3v2 tags are not being written correctly?

One thing you should know is that Amarok uses TagLib for reading and writing tags. So that's the direction you should look, I guess.

Thanks for the info.

Just a little anecdotal test I did was to install another app that uses libtag.  I installed prokyon3 and used it to write some tags.  Did not get the same behaviour.  Not totally conclusive I suppose, but it would appear that this issue is how amarok is calling libtag vs. libtag its self.