- substr: documentation ( source)
- str_replace: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
$fileName = "140908181323-q6nr12vo-8900001-08031970805-byC1.mp3";
echo date('Y-m-d H:i:s', strtotime(str_replace("_","",substr($fileName,0,11)))).substr($fileName,12);