File naming convention for XLD encoding

xld_filename.md

IDs

as per: https://sourceforge.net/p/xld/code/HEAD/tree/trunk/XLD/XLDController.m

%n: track number
%D: disc number
%t: title
%a: artist
%T: album title
%A: album artist
%c: composer
%y: year
%g: genre
%i: isrc
%m: mcn (media catalog number)
%I: discid
%f: format

Alternate IDs (no longer used(?))

from: https://sourceforge.net/p/xld/code/HEAD/tree/trunk/XLD/XLDMetadataTextParser.m

%n: track
%N: total tracks
%d: disc
%D: total discs
%y: year
%t: title
%T: album
%a: artist
%A: album artist
%g: genre
%G: group
%c: composer
%C: comment
%o: original filename