[Flac] --keep-foreign-metadata question

[Martin Leese]

Not sure if this belongs here or in flac-dev.
I am subscribed to both, so flop it over if fits
better over there.

Looking at the Changelog for FLAC 1.2.1
(17-Sep-2007), it says:
   "With the new --keep-foreign-metadata in
    flac, non-audio RIFF and AIFF chunks can
    be stored in FLAC files and recreated when
    decoding."

Where can I find more detail on what is a
"non-audio" RIFF chunk?

Ambisonic ".amb" files are WAVE-EX files with
a non-standard GUID in the 'fmt ' chunk.  I
want to work out is this can now be preserved
in FLAC files.  (And, I am interested in
metadata anyway.)

Many thanks,
Martin
-- 
Martin J Leese
E-mail: martin.leese at stanfordalumni.org
Web: http://members.tripod.com/martin_leese/