sub btween (\%$$)
  {
    my ($hash, $from, $until) = @_;

    return scalar(grep { $hash->{$_}->{VLENGTH} >= $from &&
                         $hash->{$_}->{VLENGTH} < $until }
                  keys(%{$hash}));
  }

print "There are ", btween(%hash, 0, 60), " clips between 0-1 minutes\n";