# Change AAC file type to "Mastered for iTunes"
**URL:** https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352
**Category:** Support
**Created:** [May 6, 2019, 9:27am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352 "2019-05-06T09:27:44Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 9:27am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/1 "2019-05-06T09:27:45Z")
Hello,
Hello,
I would like to know if it was possible to change the "type" with Mp3tag?
I would like to put "bought" more in my tags.
Thank you.
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 9:34am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/2 "2019-05-06T09:34:01Z")
Which tag field does "type" refer to?
Have a look at the extended tags dialogue (Alt-T) and check the field name that shows "Fichier audio AAC acheté".
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 9:35am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/3 "2019-05-06T09:35:00Z")
Exactly, I do not know if there is a field for that ... I would like to put that I bought the song in tag
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 9:39am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/4 "2019-05-06T09:39:57Z")
There is no dedicated field that shows that a file as been bought.
See the help on the list of standard fields:
> **[Tag Field Mappings – Mp3tag Documentation](https://docs.mp3tag.de/mapping/)**
>
> Overview of all available tag fields, their names in Mp3tag, and how they are mapped to the internal structures of the different tag formats. Mp3tag is the universal Tag Editor.
and choose one. Or if you do not want to use such a field, create a user-defined one.
Or is that, what you see a definition burried in the depths of the OS?
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 9:41am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/5 "2019-05-06T09:41:44Z")
How can we create a field like this?
I would like to create to be marked as done and also to put "Mastered for iTunes" ...
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 9:48am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/6 "2019-05-06T09:48:06Z")
To create a user-defined field ...
open the extended tags dialogue
click the "new" button
enter a name for the field, e.g. achete
enter data for the field, e.g. done
save the modifications by closing all dialogues with OK.
If you need that field more often, you can create an additional column or an entry in the tag panel. Please see the help for that.
> **[File List – Mp3tag Documentation](https://docs.mp3tag.de/customization/file-list/)**
>
> Customization options for the File List, including adding, removing, hiding, and rearranging of columns. Mp3tag is the universal Tag Editor.
[https://docs.mp3tag.de/customization/tag-panel](https://docs.mp3tag.de/customization/tag-panel)
Also, it is possible to add that data with an action of the type "format value" for that field.
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 9:51am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/7 "2019-05-06T09:51:58Z")
It's extended tags dialogue ? Or not ?
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 9:53am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/8 "2019-05-06T09:53:40Z")
Yes, that is the extended tags dialogue.
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 9:55am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/9 "2019-05-06T09:55:28Z")
> [@ohrenkino](#):
>
> To create a user-defined field ...
> open the extended tags dialogue
> click the "new" button
> enter a name for the field, e.g. achete
> enter data for the field, e.g. done
> save the modifications by closing all dialogues with OK.
>
> If you need that field more often, you can create an additional column or an entry in the tag panel. Please see the help for that.
> [https://docs.mp3tag.de/customization/file-list](https://docs.mp3tag.de/customization/file-list)
> [Tag Panel – Mp3tag Documentation](https://docs.mp3tag.de/customization/tag-panel)
>
> Also, it is possible to add that data with an action of the type "format value" for that field.
So, I put this and in value ?
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 9:56am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/10 "2019-05-06T09:56:30Z")
I don't know - you said something about "done" and
> [@aurelienvm](#):
>
> "Mastered for iTunes"
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 9:57am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/11 "2019-05-06T09:57:47Z")
When I do that, it does not change anything in the information on iTunes...
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 10:00am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/12 "2019-05-06T10:00:28Z")
Ah: now we have to find a field that can hold this information and also be shown by iTunes.
as I said: as there is no dedicated field for that you probably have to "mis-use" one for that purpose - so feel free to pick one from the list of standard fields that is also supported by iTunes.
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 10:01am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/13 "2019-05-06T10:01:56Z")
I will wait for an update of MP3Tag or a script ...
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [May 6, 2019, 10:50am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/14 "2019-05-06T10:50:36Z")
???
If you have a look at the list of fields in the help, then you will find that iTunes does not support all of them.
So what should the update of MP3tag change in iTunes?
Also, it is not certain, that iTunes saves all the information in tags or reads all of it from there as iTUnes maintains its own database.
Apparently, there is a field shown as "Purchased by" - but see the thread about that field:
> [@\[REQUEST\] iTunes Purchased By](https://community.mp3tag.de/t/request-itunes-purchased-by/15735):
>
> Can anyone make a script to edit the "Purchased By" field on iTunes? Thanks slight_smile
Looking at the dump again, I see "MASTERED" as field (which is most likely a user-defined field - does that show in iTunes?) but your dump does not show a field called TYPE as it stops at TITLESORT...
---
### Author:  [@aurelienvm](https://community.mp3tag.de/u/aurelienvm)
#### Post date: [May 6, 2019, 10:54am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/15 "2019-05-06T10:54:06Z")
> [@ohrenkino](#):
>
> there is a field shown as "Purchased by"
Yes, there is a field shown as "Purchased by".
But I would like to put the tag "Mastered for iTunes". There is no bread for that ....
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [May 6, 2019, 3:36pm UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/16 "2019-05-06T15:36:28Z")
> [@aurelienvm](#):
>
> I would like to put the tag "Mastered for iTunes"
It's not possible to change this with Mp3tag.
---
### Author:  [@TheY2KGuy](https://community.mp3tag.de/u/TheY2KGuy)
#### Post date: [November 20, 2023, 12:56am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/18 "2023-11-20T00:56:44Z")
> It's not possible to change this with Mp3tag.
is it possible at all?
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [November 20, 2023, 6:30am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/19 "2023-11-20T06:30:57Z")
Well, who knows?
As this is the forum for the program MP3tag, the answer is still valid: not with Mp3tag.
It is probably possible for the folks who put the string there initially.
You would have to look somewhere else to find a way.
Or recode the file and assign new tags.
---
### Author:  [@TheY2KGuy](https://community.mp3tag.de/u/TheY2KGuy)
#### Post date: [November 20, 2023, 10:27pm UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/20 "2023-11-20T22:27:31Z")
Not sure if this helps, but here's this [post on another forum](https://hydrogenaud.io/index.php/topic,106283.0.html)
it mentioned the "byte 00 00 00 04 at the end of mode", it got me curious
here's also some pics from the hex editors of 2 legitimate songs from itunes, I noticed a pattern on it.
---
### Author:  [@AreDigg](https://community.mp3tag.de/u/AreDigg)
#### Post date: [November 22, 2023, 11:15am UTC](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352/21 "2023-11-22T11:15:06Z")
> [@TheY2KGuy](#):
>
> it mentioned the "byte 00 00 00 04 at the end of mode", it got me curious
Isn't that how to set HD video? Or maybe it has more purposes?
[Next page](https://community.mp3tag.de/t/change-aac-file-type-to-mastered-for-itunes/45352.md?page=2)