How to extract Xtra atom from MP4 file?

Question

Can one dump/extract the Xtra atom from an MP4 file ? I am looking for a solution on a linux system (debian/jessie if possible).

Apparently this atom is used by WMP, as per link. I'd like to be able to use such information (rating, publisher or leveling inf) and pass that to my DLNA server (minidlna).

Currently all I see using AtomicParsley is:

[...]
                     Atom data @ 678585 of size: 529, ends @ 679114
         Atom Xtra @ 679114 of size: 206, ends @ 679320 ~
Atom free @ 679320 of size: 48, ends @ 679368
Atom mdat @ 679368 of size: 248835382, ends @ 249514750

 ~ denotes an unknown atom
[...]

And same thing with MP4Box:

 <UDTARecord Type="Xtra">
 <UnknownBox>
 <BoxInfo Size="206" Type="Xtra"/>
 </UnknownBox>

Which cannot be used/parsed.

Answer 1

I've reported the issue on Debian bug tracker here, as well as upstream here.

Really the only available reference implementation can be found here.