#543 Suppot of MP4/M4A rati "Rating" metadata

[Jamil]

Rating appears incorrect for MP4/M4A tag information. I often store ratings as an integer from the value one through five in M4A audio tags. Mediainfo version 19.09 does not correctly display the rating tag data. It instead displays it as "rati : (Binary)". The actual tag name is Rating.

It appears MP4/M4A tag data is not stored in the file as plain text. Mediainfo has issues specifically with the Rating tag. All other tag data displays properly. Please see attached screenshot showing the issue as well as an example file for analysis.

[Jerome Martinez]

Ticket moved from /p/mediainfo/bugs/1121/

[Jerome Martinez]

Rating appears incorrect

Not really incorrect, not a bug, just not supported.

I often store ratings as an integer from the value one through five in M4A audio tags.

Which tool was used for that?
I don't find any spec for this field, I find this info about "rtng" atom for rating, or com.apple.quicktime.rating.user (developer.apple.com) but is a 32-bit float value 0.0-5.0, your "rati" atom is a 16-bit integer.

Not difficult to implement, just willing to be sure I implement something commonly accepted.

[Jamil]

I set the rating using the latest version of Tag&Rename v3.9.15. This is a popular batch tag editor. I checked the options for MP4/M4A, and there is an option to always save/update Windows atom when saving tag changes. I just turned that option on and saved the tag again. It still contains a rati atom as you noted. However, now windows file properties shows the rating too:

Attached is the file that now also contains the Windows atom.

[Jamil]

I have been experimenting with this to find a solution with the current version of Mediainfo. It appears that Tag&Rename does not properly write the rating tag. RATI for rating does not match iTunes rating. Also, the latest version of iTunes available no longer writes the rating to M4A files at all. It appears to be stored only in its internal database. Out of all the popular tag editing tools currently available, I cannot find a single one that supports writing the rating tag. Tag&Rename is the only one I have been able to find that writes rating (for M4A files it does it incorrectly).

I did find that tag data may also be stored that is compatible with iTunes as plain text. Also, Mediainfo supports this plain text entry. I have a test file I had been experimenting to find this, and the current version of Mediainfo shows the rating without issue from this plain text tag. This is good news in that it simplifies adding the rating tag to my files.

At the end of this attached binary file the RATING tag exists as plain text. Mediainfo displays it correctly without issue. With this being the case, there is no need for change.