- var_dump: documentation ( source)
- sscanf: documentation ( source)
<?php
$time = '00:02:14.31';
sscanf($time, '%d:%d:%d.%d', $hours, $minutes, $seconds, $microseconds);
$total = ($microseconds * 100)
+ ($seconds * 1000)
+ ($minutes * 60 * 1000)
+ ($hours * 60 * 60 * 1000);
var_dump($total);