-my $prev_hour = 0;
-my $prev_min = 0;
-my $prev_sec = 0;
-my $new_duration = DateTime::Duration->new(years => 1900, hours => $prev_hour, minutes => $prev_min, seconds => $prev_sec);
-my $duration_format = DateTime::Format::Duration->new(pattern => '%H:%M:%S.%3N', normalize => 1);
+my $chapter_timecode = DateTime::Duration->new(years => 2000, hours => 0, minutes => 0, seconds => 0);
+my $timecode_format = DateTime::Format::Duration->new(pattern => '%H:%M:%S.%3N', normalize => 1);