[Mp4-tech] Query about user data atom

[Hans-Juergen Bardenhagen]

Hi Kaushik,
>     I need to retrieve user defined information like movie album,
> movie title, movie author, copyright. I think these informations
> should be available under user data atom under the movie atom and
> within the user data atom these information should be available in
> the form of atoms. If that be the case what should be the format of
> each atom structure, e.g. what should be its type, its content etc.

Maybe it would be useful for you to have a look at the way how Menno  
Bakker implemented tagging MP4 files in the input plugin of foobar2000,  
a rather new audio player. You can find the source code of foo_mp4.dll  
(the plugin) in the CVS of the FAAC project on SourceForge, either with  
anonymous CVS access or through looking at the directories with your  
browser.
http://sourceforge.net/projects/faac/
This method is compatible to the Apple iTunes4/ipod tagging which uses  
these atoms in the same way. See also my other announce about direct  
tagging and gapless playback for MP4 files with foo_faac.dll (FAAC  
output plugin for foobar2000) from today.