# Track numbers

**URL:** https://community.mp3tag.de/t/track-numbers/10473
**Category:** Support
**Created:** [May 26, 2010, 5:31am UTC](https://community.mp3tag.de/t/track-numbers/10473 "2010-05-26T05:31:32Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![mjcm](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/m/9d8465/32.png) [@mjcm](https://community.mp3tag.de/u/mjcm)
#### Post date: [May 26, 2010, 8:47am UTC](https://community.mp3tag.de/t/track-numbers/10473/5 "2010-05-26T08:47:56Z")

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> [@auldyin](#):
>
> I have a mixture of MP3, MP4 and M4A files some of which are numbered 1,2,3 etc and others 01,02,03.  
> Why is this?

[TAGs: iTunes M4a vs MP3](https://community.mp3tag.de/t/2556/12)

"This is because the standard MP4 tag atom (TRKN) can't store leading zeros.  
And also FYI in m4a tags the track number and the total amount of tracks are  
mapped to two different fields. TRACK and TOTALTRACKS

You can see it in the extended tag view [Alt+t].

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