Import/Export mp4 tags from/to text file

[GoogleCodeExporter]

Hi,

Many thanks for this great tools.

I would to know if it is possible to add an import/export functions to mp4tags 
(as you can do with flac/metaflac with --import-tags-from= or 
--export-tags-from=).

ffmpeg support some tags but not iTunes tags (as category, ...)

It could be very useful to have the possibility to 
- export tags from an mp4 file then re encode it or do any modification and the 
import exported tag to the new mp4 file
- create some text files with all needed tags and then batch import each text 
file on each mp4 file

Kind Regards

Original issue reported on code.google.com by fma211...@gmail.com on 27 Feb 2015 at 10:07