#!/usr/bin/perl

use strict;
use warnings;

use Time::Piece;
use Time::Seconds;

my $DATEFORMAT
  = '%d.%m.%y %H:%M:%S';    # siehe http://www.unix.com/man-page/FreeBSD/3/strftime/

my $from = "05.12.14 12:00:44,050000";
$from =~ s/,\d+//;
my $to = "05.12.14 12:00:44,070425";
$to =~ s/,\d+//;

my $t1 = Time::Piece->strptime( $from, $DATEFORMAT );
my $t2 = Time::Piece->strptime( $to,   $DATEFORMAT );
if ( $t1 == $t2 ) {
    $t1 += ONE_MINUTE;
    $t1 = $t1->strftime($DATEFORMAT);

    $t2 -= ONE_MINUTE;
    $t2 = $t2->strftime($DATEFORMAT);
}

print $t1, "\n", $t2, "\n";

=comment

Ergibt:

05.12.14 12:01:44
05.12.14 11:59:44