foreach my $infile (@files) {
    print $infile . "\n";
    # escape spaces
    # $infile =~ s[ ][\\ ]g;
    my $outfile = $infile;
    $outfile =~ s/\.(?:mkv|avi)\z/m4v/;
    system "$handbrake -i '$infile' -o '$outfile' --preset=$preset"; # without escaped spaces
    #system "$handbrake -i $infile' -o $outfile --preset=$preset"; # with escaped spaces
}