added missing encode of --tag-only-filename value

Closes #448

get_iplayer

@@ -3987,7 +3987,7 @@ sub tag_file {
 	my $prog = shift;
 	if ( $opt->{tagonly} ) {
 		if ( $opt->{tagonlyfilename} ) {
-			$prog->{filename} = $opt->{tagonlyfilename};
+			$prog->{filename} = main::encode_fs($opt->{tagonlyfilename});
 			(undef, undef, $prog->{ext}) = fileparse($prog->{filename}, qr/\.[^.]*/);
 			$prog->{ext} =~ s/^\.//;
 		}