# Something like this:
use IO::Select;

my $bladeenc_cmd = 'bladeenc -whatever args';
my $cdparanoia_cmd = 'cdparanoia -whatever else args';

open P1, "$bladeenc_cmd|" or die "bladeenc: $!";
open P2, "$cdparanoia_cmd|" or die "cdparanoia: $!";

local $SIG{PIPE} = sub { warn "pipe closed"; }

my $s = IO::Select->new();
my $timeout = 100;    # msec(?)

$s->add(\*P1);
$s->add(\*P2);

my @ready;
while (@ready = $s->can_read($timeout)) {
  foreach my $fh (@ready) {
     if ($fh == \*P1) {
       my $line = <$fh>;
       # write to first window
     }
     if ($fh == \*P2) {
       my $line = <$fh>;
       # write to second window
     }
  }
}

# you get the idea ...