# $mid(%\_file\_mod\_datetime%,5,4)
**URL:** https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307
**Category:** Support
**Created:** [April 8, 2012, 3:46pm UTC](https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307 "2012-04-08T15:46:15Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Denis\_Bisson](https://community.mp3tag.de/u/Denis_Bisson)
#### Post date: [April 8, 2012, 3:46pm UTC](https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307/1 "2012-04-08T15:46:15Z")
Hi!
This one is hard to report and I won't be surprised if you're not able to duplicate. But I'll do my best. I am using MP3TAG version 2.50. I am a very enthousiam user and I've made my 50$ donation for sure. But here is a little slight problem that I can go over easily but now I am taking the time to report it.
Let's suppose I want to rename the filename of an entry from the modified date of the file itself. I will use ALT-1, so "TAG - FILENAME".
If I type directly "%\_file\_mod\_datetime%", the application uses "06042012 23136 PM" for example with a sample file.
Let's suppose I am interrested to use only the YEAR in my name, I would use "MID$" and assume I need to type "$mid(%\_file\_mod\_datetime%,5,4)" to get my 2012...
**06042012**
**12345678
\_\_\_\_1234**
BUT NOT! When I do that, it will report simply "420"!!!
It looks like I need to type one position more than expected with one character lenght longer than expected!
If I want my "2012" reported, I need to type "$mid(%\_file\_mod\_datetime%,6,5)" with the 5!!!
Oh! I see we can attached a file? I will attached a screenshot of what I am talking about then.
See the preview of the resulting name under in the requester.
I typed the "\_" to help to see and make sure there is no annoying space inserted.
The capture I attached there shows the thing:
1st) you see the result of simply "%\_file\_mod\_datetime%"
2nd) you see what I got with "$mid(%\_file\_mod\_datetime%,5,4)"
3rd) you see what I got with "$mid(%\_file\_mod\_datetime%,6,5)"
It could be nice if "%\_file\_mod\_datetime%" would report the same thing in ALL places. When proving tag for album name for example (and it's an example), the date is reported differently...
Thanks.
Denis.
---
### Author:  [@DetlevD](https://community.mp3tag.de/u/DetlevD)
#### Post date: [April 8, 2012, 4:00pm UTC](https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307/2 "2012-04-08T16:00:28Z")
Please try out your example and check the result using the converter "Tag-Tag" preview and come back to report.
Oh I see you did it already.
So ... what do you think ... what is the difference between a filename value and a tag-field value?
By the way ... for this example format string ...
**%\_file\_mod\_datetime%'~~'$mid(%\_file\_mod\_datetime%,1,4)**
... with System Date Time set according to ISO 8601 ...
... the result is in converter "Tag-Tag" preview ...
**2012-04-05 16:26:21~~2012**
... the result is in converter "Tag-Filename" preview ...
**2012-04-05 162621~~2012**
Both previews are correct.
DD.20120408.2010.CEST
---
### Author:  [@Denis\_Bisson](https://community.mp3tag.de/u/Denis_Bisson)
#### Post date: [April 8, 2012, 4:25pm UTC](https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307/3 "2012-04-08T16:25:21Z")
> [@DetlevD](#):
>
> Please try out your example and check the result using the converter "Tag-Tag" preview and come back to report.
> Oh I see you did it already.
> So ... what do you think ... what is the difference between a filename value and a tag-field value?
>
> By the way ... for this example ...
> _%\_file\_mod\_datetime%==$mid(%\_file\_mod\_datetime%,1,4)_
> ... with System Date Time set according to ISO 8601 the result is ...
> _2012-04-05 16:26:21==2012_
>
> DD.20120408.2005.CEST
Hello Sir!
I am not sure about the purpose of your reply. You've seem to have replied to 99% of all the cases I've read here so I am sure you're very good and it's my fault if I don't understand... But still, I don't. Are you asking a question? Are you explaining it's normal? Am I doing something wrong?
If your replied is to say "That's normal the expression %\_file\_mod\_datetime% does not report the same thing when I want to use it to rename a filename then when I want to use it into a MP3 tag itself", that's fine. Even if I don't see why an expression a software would use to rename something is different from a situation to another, that's fine.
For having done many programming in the last twenty years, I know reporting the datetime is something that has been "inconsistant" for many many many reasons like DOS legacy, Windows versions, FAT versions, Windows regional settings, etc... BUT inside one software, I was expecting that when we would use an expression to report the date, it would be the same through the same software, in other words, that if "%\_file\_mod\_datetime%" is 2012-04-05" for using it in renaming the file, it would be the same for using it in a tag. Certainly I would understand that MAYBE from a computer to another the filed would be reported differently (unfortunately...) but I was expecting that once on a specific computer, for ONE software itself the same expression would report the SAME thing from a place to another...
But that's fine. My main observation was ragarding the MID$ that seems strange used in combinaison of the %\_file\_mod\_datetime%. I've seen that in the past a few times, I simply change the parameter to make it work and that's not a big deal. Today I had time so I took the time to report it. Me I like when my colleagues take the time to report an error or what seems to be an error in the internal application I do for us so I though I could do the same now for someone else. That's simply it.
Dennis.
---
### Author:  [@DetlevD](https://community.mp3tag.de/u/DetlevD)
#### Post date: [April 8, 2012, 4:38pm UTC](https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307/4 "2012-04-08T16:38:26Z")
> [@Denis Bisson](#):
>
> ... I am sure you're very good and it's my fault if I don't understand ... Are you explaining it's normal? Am I doing something wrong? ...
%\_file\_mod\_datetime% returns a text string, which contain some characters not to be allowed to be used in the file sytem.
The "Tag-Filename" preview removes such forbidden characters automatically, that's all.
I tend to say it is not a heavy bug.
But there might be a quirk in the sequence of applying the validating rule.
See there ...
[Converter Tag - Filename validates part of format string before applying other functions around](https://community.mp3tag.de/t/12727/1)
DD.20120408.2058.CEST
---
### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [February 9, 2026, 12:23pm UTC](https://community.mp3tag.de/t/mid-file-mod-datetime-5-4/13307/5 "2026-02-09T12:23:46Z")