#!/usr/bin/perl

use strict;
use warnings;

my $in_qfn  = '...';
my $out_qfn = '...';

open( my $in_fh, "<:raw", $in_qfn )
   or die( "Can't open `$in_qfn`: $!\n" );

open( my $out_fh, ">:raw", $out_qfn )
   or die( "Can't create`$out_qfn `: $!\n" );

my $int_size = 4; # length( pack( "L<", 0 ) );

local $/ = \( 8 * 1024 );

while ( my $in_buf = <$in_fh> ) {
   length( $in_buf ) % $int_size == 0
      or die( "Invalid input file `$in_qfn`\n" );

   my @ints = unpack( "L<*", $in_buf );

   # Something that modifies `@ints` here.

   print( $out_fh pack( "L<*", @ints ) )
      or die( "Error writing to `$out_qfn`: $!\n" );
}

close( $in_fh )
   or die( "Error reading from `$in_qfn`: $!\n" );

close( $out_fh )
   or die( "Error writing to `$out_qfn`: $!\n" );