# \[F\] MP3Tag's use of Unicode in TLEN field is not ID3V2.3 compliant
**URL:** https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209
**Category:** Fixed Bugs
**Tags:** bug-fixed
**Created:** [October 26, 2009, 2:24pm UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209 "2009-10-26T14:24:09Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@gvm](https://community.mp3tag.de/u/gvm)
#### Post date: [October 26, 2009, 2:24pm UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209/1 "2009-10-26T14:24:09Z")
MP3Tag uses Unicode when writing the TLEN field.
However, at [http://www.id3.org/id3v2.3.0#sec3.3](http://www.id3.org/id3v2.3.0#sec3.3) it says explicitly:
> [@](#):
>
> All numeric strings and URLs are always encoded as ISO-8859-1.
This seem pretty conclusive.
This has become significant because of Microsoft's recent "security update" KB968816, which no longer permits (non-compliant) Unicode for TLEN, and now refuses to play such files.
More details here: [http://www.microsoft.com/communities/newsg...78-39d7b355910b](http://www.microsoft.com/communities/newsgroups/en-us/default.aspx?dg=microsoft.public.windowsxp.music&tid=93b45385-c345-4fd9-9b54-a35c4a8f6d0f&cat=&lang=&cr=&sloc=&p=1&mid=e7311eeb-04aa-4009-a078-39d7b355910b)
and here: [http://www.microsoft.com/communities/newsg...amp;m=1&p=1](http://www.microsoft.com/communities/newsgroups/list/en-us/default.aspx?dg=microsoft.public.windowsmedia.player&tid=3216f2df-39eb-4536-b4a2-b59a5f00dc60&cat=en_us_b80c408d-117a-4d9c-9ba5-55785432b592&lang=en&cr=us&sloc=en-us&m=1&p=1)
and here: [/t/9208/1](https://community.mp3tag.de/t/9208/1)
Note: these links describe the issues and the effects, but it has only just become apparent that the problem is with MP3Tag, rather than WMP10.
Regards,
gvm
p.s. Other than that, MP3Tag is an excellent ID3 tag editor!
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### Author:  [@gvm](https://community.mp3tag.de/u/gvm)
#### Post date: [October 27, 2009, 5:48pm UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209/2 "2009-10-27T17:48:55Z")
> [@gvm](#):
>
> MP3Tag uses Unicode when writing the TLEN field.
I should probably have included a bit more information on why this non-compliance is important - I've been working on debugging this issue for so long, I tend to forget that not everyone will immediately see the consequences (though I'm sure that many will).
The reason that precise compliance is _critical_ is that, although some (or even most) MP3 players today will ignore apparently trivial issues such as "wrong format in length field", those same players are perfectly within their rights to change their behaviour and reject these files.
This has recently happened with Microsoft's security update KB968816. This has changed the behaviour of Windows Media Player (version 10 for certain, probably others too) so that it now refuses to play files with a non-compliant TLEN field.
This means that most\* files which have a TLEN field and have been edited with a recent version of MP3Tag are now unplayable using Windows Media Player. This should be a concern even for non-users of WMP, since other players may also follow this strict compliance at some future date, rendering our MP3 libraries unplayable.
Regards,
gvm
-
- I say "most" because not every edit will rewrite the TLEN field, but it can be rewritten by editing unrelated fields (just based on observation).
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [October 29, 2009, 11:46am UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209/3 "2009-10-29T11:46:09Z")
Thanks for reporting! I'll fix it to the next release.
Kind regards,
Florian
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [October 31, 2009, 4:47pm UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209/4 "2009-10-31T16:47:17Z")
This is now fixed with [Mp3tag v2.44f Development Build](http://developer.mp3tag.de).
Kind regards,
Florian
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### Author:  [@gvm](https://community.mp3tag.de/u/gvm)
#### Post date: [November 4, 2009, 11:24pm UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209/5 "2009-11-04T23:24:33Z")
Thanks Florian,
Regards,
gvm
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [December 28, 2018, 2:03pm UTC](https://community.mp3tag.de/t/f-mp3tags-use-of-unicode-in-tlen-field-is-not-id3v2-3-compliant/9209/6 "2018-12-28T14:03:06Z")
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