# TAGs: iTunes M4a vs MP3

**URL:** https://community.mp3tag.de/t/tags-itunes-m4a-vs-mp3/2556
**Category:** General Discussion
**Created:** [November 30, 2005, 11:34am UTC](https://community.mp3tag.de/t/tags-itunes-m4a-vs-mp3/2556 "2005-11-30T11:34:52Z")
**Posts on this page:** 1
**Showing post:** 12

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### Author: ![Florian](https://community.mp3tag.de/user_avatar/community.mp3tag.de/florian/32/5759_2.png) [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [December 5, 2005, 9:13am UTC](https://community.mp3tag.de/t/tags-itunes-m4a-vs-mp3/2556/12 "2005-12-05T09:13:11Z")

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> [@](#):
>
> Any idea why an Mp4 TRACK tag formatted with a leading zero shows up blank in iTunes but a similiar MP3 shows correctly?
> 
> \<{POST\_SNAPBACK}\>

This is because the standard MP4 tag atom (trkn) can't store leading zeros. Till now, I wanted to save the information losslessy and created a freeform atom named "track" for tracknumbers with leading zeros. Since iTunes (and probably other software too) has problems with that, I've changed this with the current [Development Build](http://developer.mp3tag.de) Mp3tag 2.43c and remove leading when saving MP4 tags.

Thanks for bringing this to my attention.

Best regards,  
~ Florian

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