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meta data - what is stored in the file and what is JUST referenced in Itunes

196 Views 5 Replies Latest reply: Nov 21, 2012 10:49 AM by Limnos RSS
Fritz Jung Calculating status...
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Nov 20, 2012 4:43 AM

wondering if anyone knows why some data is ONLY store in itunes but not pernament added to the 'get info' for the file.


example beats per minute .


I would think that ALL info added to a file in itunes would be stored in the 'get info' section of the actual file.


is there a doc that details what is store and what is not.



  • Limnos Level 8 Level 8 (36,585 points)

    I have not seen such a document, though I haven't searched the web for it.


    I don't know if mp3 and AAC/mp4 tagging support different tags.  There are different versions of tags even within one system.  I am pretty sure BPM is a part of of the tagging system for mp3s at least.  I know I have added files and seen data appear in BPM.


    There are, of course, also items where the data are stored only in iTunes, such as ratings.  Then on top of that, some data are reputedly only stored in the .itl version of the library file and not the .xml version.

  • ed2345 Level 6 Level 6 (18,435 points)



    BPM is definitely stored in the MP3 file, and will be there if you copy the file and use it somewhere else.


    Like Limnos, I have not see a nice summary, but here are the basics:


    Identifying information about the song, such as Artist, Title, Year, etc are stored as tags in the file for most audio types.  The exception is WAV files, which have limited tag capability.


    Library-specific information, such as Date Added, Last Played, Play Count, etc, are stored in the library, not in the file.


    And then there are some complicated things:


    iTunes puts the Rating in the library, even though the tag is capable of storing it (and other players, such as WMP, use the rating tag).


    Artwork is in the song file if it was added by pasting in using Get Info, but is in the Artwork folders if it was added using the Get Album Artwork command.

  • ed2345 Level 6 Level 6 (18,435 points)

    Hi Fritz,


    I can't say for sure, since I don't work with video much.  But you can make a copy of one of the troublesome files and experiment on the copy.  You are probably right about the older format being the issue.

  • Limnos Level 8 Level 8 (36,585 points)

    I think what is happening when you edit in iTunes is it creates labels it writes to the library file but these are not embedded in the actual file.  The same thing can happen with artwork fetched from the iTunes Store but not actually embedded in the files (but I do know a solution for artwork).


    Theoretically WAV format is the only common format that is supposed to present problems with embedding tags.  In practice I have found issues with iTunes and tagging with pretty much all other formats (including .mov, .aiff and .mp4) except mp3 in situations.  Sometimes it works, but frequently it does not.  mp3 is the only format I have found to reliably allow editing and transfer with both iTunes and other applications.


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