# Track Number Format, Padding with 0
**URL:** https://community.mp3tag.de/t/track-number-format-padding-with-0/66696
**Category:** Support
**Created:** [December 2, 2024, 3:42am UTC](https://community.mp3tag.de/t/track-number-format-padding-with-0/66696 "2024-12-02T03:42:09Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Whitburn\_Collector](https://community.mp3tag.de/u/Whitburn_Collector)
#### Post date: [December 2, 2024, 3:42am UTC](https://community.mp3tag.de/t/track-number-format-padding-with-0/66696/1 "2024-12-02T03:42:09Z")
Hello:
I selected three video files in MP3Tag and attempted to write the track number "05" to each of the files. After saving the changes to the three files I noticed that only one of the three was updated showing "05" in the track field, the other two show up as "5". I noticed that one file, the one that was updated to track number "05" was an mp4 file, the other two that didn't update as expected were m4v files. I'm I running up against a limitation in the tag structure for m4v files?
I've also had experience with the assign track number feature not padding track numbers 1-9 with a "0" despite having the "leading zeros for track numbers" option being marked as checked. I just remember the file formats selected when using the assign track number feature.
Rob
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [December 2, 2024, 6:01am UTC](https://community.mp3tag.de/t/track-number-format-padding-with-0/66696/2 "2024-12-02T06:01:24Z")
> [@Whitburn\_Collector](#):
>
> the one that was updated to track number "05" was an mp4 file, the other two that didn't update as expected were m4v files
AFAIK the mp4 tag format does not support leading zeros at all. So check what is wrong with the mp4 file.
> [@Whitburn\_Collector](#):
>
> not padding track numbers 1-9
Yes, this is always the case.
If you really want leading zeros, then, after you have assigned the correct ascending number, use an action of the type "Format value" for TRACK
Format string: `$num(%track%,2)`
this works only on files with the total number of tracks saved in TRACK.
See also here:
> [@In mp3tag v.3.27a, I can no longer enter track numbers in format xx/xx e.g. 04/10](https://community.mp3tag.de/t/in-mp3tag-v-3-27a-i-can-no-longer-enter-track-numbers-in-format-xx-xx-e-g-04-10/66685):
>
> In mp3tag v.3.27a, I can no longer enter track numbers in format xx/xx e.g. 04/10. I used to be able to enter track numbers of the type XX/XX e.g. 04/10, but in the update to mp3tag v.3.27a, I can no longer do this. I have tried using the auto-numbering wizard, tried entering a leading zero to the digit e.g. 04, but nothing works for me. It used to happen automatically- I just used to enter my track field with the format xx/xx e.g. 04/10 without any problems, but I can't do it since the updat…
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### Author:  [@Whitburn\_Collector](https://community.mp3tag.de/u/Whitburn_Collector)
#### Post date: [December 3, 2024, 5:49am UTC](https://community.mp3tag.de/t/track-number-format-padding-with-0/66696/3 "2024-12-03T05:49:19Z")
Thanks for the formatting command for track numbers, I don't think there is anything obviously wrong with the MP4 file in questions, it plays fine which is my main concern. - Rob
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [January 2, 2025, 5:49am UTC](https://community.mp3tag.de/t/track-number-format-padding-with-0/66696/4 "2025-01-02T05:49:46Z")
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