I use the following to uncompress shorten files (go etree!) into wave files and mp3 files at the same time. I'm sure you could modify this to suit your needs.

$shorten_path = '/windows/command/shortn32';
$mp3_encoder = '/mp3/bladeenc/bladeenc';

opendir DIR, '.';
while (my $file = readdir(DIR)) {
  next unless $file =~ /\.shn$/i;
  ($file_out = $file) =~ s/\.shn$/.wav/i;
  `$shorten_path -x  $file $file_out`;
  `$mp3_encoder -quit -quiet $file_out`;
}
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