Add this

#fix dir
for my $i (@arr){
    $i->{dir} = $1 if $i->{path} =~ m{^(.+)/};
}
[download]

one step closer :)

/c/
/c/a1.mp3
/c/a2.mp3
/c/aa/
/c/bb/
/c/bb/aa1.mp3
/c/bb/aa2.mp3
/c/cc/
[download]