http://xiph.org/vorbis/doc/Vorbis_I_spec.html#vorbis-spec-comment
"The field name is case-insensitive and may consist of ..."

--- libogg-vorbis-header-perl.orig/Header.pm
+++ libogg-vorbis-header-perl/Header.pm
@@ -71,7 +71,6 @@
 	while ($#comments >= 0) {
 		my $key = shift @comments;
 		$key =~ s/[^\x20-\x3C\x3E-\x7D]//g;
-		$key = lc($key);
 		my $val = shift @comments;
 		$val =~ s/[^\x20-\x7D]//g;
 		push @{$self->{COMMENTS}->{$key}}, $val;