use 5.010;
use strict;
use warnings;
use open qw(:utf8 :std);

use Encode::MIME::EncWords;
use Encode qw/encode decode/;

my $fname = '=?gb2312?B?MzYw0MLOxbzgsuItMTItMDEtQ2hpIFNpbXAudHh0?=';
say decode('MIME-EncWords', $fname);