Convert Cowon C2 NPD to BMP

#!/usr/bin/perl

use strict;
use Data::Dumper;

my $bmp_header = join '', map (chr, 0x42,0x4d,0xf6,0xd4,0x04,0x00,0x00,0x00,0x00,0x00,0x36,0x00,0x00,0x00,0x28,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x84,0x01,0x00,0x00,0x01,0x00,0x18,0x00,0x00,0x00,0x00,0x00,0xc0,0xd4,0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00);
opendir (DIR, ".") || die "$!";
my @files = grep /\.npd$/i, grep !/^\.\.?$/, readdir DIR;
closedir DIR;

foreach my $file (@files) {
  my $fn = $file; $fn =~ s/\.npd$/.bmp/i;
  open (fo, ">".$fn) || die "$!";
  binmode fo;
  print fo $bmp_header;
  open (fh, "<".$file) || die "$!";
  binmode fh;
  for(my $i=0; $i<240;$i++) {
    seek fh, -((320*3*2)+($i*320*3)), 2;
    read fh, my $buf, 320*3;
    for(my $c=0;$c<320;$c++) { substr($buf, $c*3+2,1, substr($buf, $c*3, 1, substr($buf, $c*3+2,1))); }
    print fo $buf;
  }
  close fh;
  close fo;
}