[Mp4-tech] Using the udta atom in a 3GPP file

[Shailendra Singh]

Hi All,
If an application creates a 3GPP file containing a udta atom, and ensures
that the udta atom is placed correctly and the length of the atom is coded
correctly, is it (the application) allowed to store any arbitrary data in
the udta atom?
The QuickTime File Format Specification states: "You may create new data
atom types that your own application recognizes. Applications should ignore
any data atom types they do not recognize."
However, ISO/IEC 14496-12 (ISO base media file format) only says : "This box
contains objects that declare user information about the containing box and
its data (presentation or track). The User Data Box is a container box for
**informative user-data**. This user data is formatted as a set of boxes
with more specific box types, which declare more precisely their content."
I am not sure ISO/IEC 14496-12 allows storing arbitrary data in a udta atom,
which QuickTime File Format Specification explicitly allows. Is there an
ambiguity here?
Regards,
Shailendra
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