Tagging m4p (iTunes Music Store) Files

I've searched a bunch, but can't seem to find any info on using mp3tag to tag/re-tag files purchased from the iTunes Music Store. They are aac-encoded files that have an .m4p extension.

I added "*.m4p;" to the filetype filter in the options, but the files still don't show up in the main window.

Any ideas?


Adding custom extensions to the list has no effect. You can only use it to remove extensions and make Mp3tag ignore these files then.

I don't know if it is save to edit m4p files in Mp3tag (a first test from me says yes), if you want to try it you should work with copies first. Rename them to m4a
And then please test if iTunes still plays the files. If it works, maybe m4p can become a supported extension.

Thanks for the clarification. If you remove a supported extension temporarily, can you then add it back so that mp3tag will again recognize that filetype?

Testing done and it appears successful to me too!

  1. Copied an m4p (iTunes store, protected aac) file.
  2. Changed the copy to an m4a extension
  3. Loaded the copy into mp3tag, appeared to load fine.
  4. Edited tags and saved changes to the copied file.
  5. Added the copied file to the itunes library (still with m4a extension). Modified tags showed up as expected. File played fine.
  6. Deleted file from itunes library and changed extension back to m4p.
  7. Added the file back to the library - everything still seemed to behave as expected.

I tried a couple of other files, all with the same positive results.

At least from this user's perspective, it would seem that m4p files could be supported.

As far as I know, the m4p files are just regular m4a files (aac encoding) that have a few additional quicktime atoms to handle the FairPlay DRM. I don't know if adding/removing tags would change the atom order, and even if it did -- I don't know if that order matters....


So try to push harder, remove all tags at once, try the foobar feature 'rebuild stream' and such stuff against the m4p file.

m4p = music for people
m4p = music for pecuniary
what does it mean exactly?


'P' = Protected :frowning: (uses the iTunes DRM)

Further testing shows that everything continues to work as expected:

  • Renaming files to 'm4a' then erasing all tags with mp3tag works fine -- files playback in apps that can handle the m4p filetype (iTunes, MediaCenter)
  • Using the 'optimize mp4' function of mp3tag does not affect file playback.
  • Tags are not read and files not playable in foobar no matter if the extension is m4p or m4a. This is expected behavior since foobar doesn't handle the DRM.
  • Using the 'optimize mp4 layout' function in foobar does not affect file playback in other players.

I never found the 'rebuild stream' feature in foobar (v0.9.4.1)....

Maybe the next developer build can have this as a supported filetype for wider testing?


But some atoms are deleted, check your information tab in itunes.

Hmmm...I don't see it.

Any m4p file I optimize with mp3tag/foobar still has all of its information visible to me in iTunes.


Including the label (EMI, Sony, whatever), explicit or clean lyrics...?

Yep. Everything is the same looking at all of the tabs in the iTunes info (except for the kind, which reads 'protected aac audio file' or 'aac audio file' depending on the extension of the file).

Should I be looking for something specific?