Yeah, I know where the problem resides. It’s line #669 of smartyoutube.php:
preg_match_all( "/((http(v|vh|vhd)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?youtube\.com\/watch(\?v\=|\/v\/|#!v=)([a-zA-Z0-9\-\_]{11})([^<\s]*))|((http(v|vh|vhd)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?youtu\.be\/([a-zA-Z0-9\-\_]{11}))|((http(v|vh|vhd)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?metacafe\.com\/watch\/([a-zA-Z0-9\-\_]{7})\/([^<^\/\s]*)([\/])?)|((http(v|vh|vhd)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?vimeo\.com\/([a-zA-Z0-9\-\_]{8})([\/])?)|((http(v|vh|vhd)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?liveleak\.com\/view(\?i\=)([a-zA-Z0-9\-\_]*))|((http(v|vh|vhd)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?facebook\.com\/video\/video.php\?v\=([a-zA-Z0-9\-\_]*))|((http(vp|vhp)?:\/\/)?([a-zA-Z0-9\-\_]+\.|)?youtube\.com\/(view_play_list\?p\=|playlist\?list\=)([a-zA-Z0-9\-\_]{18,34})([^<\s]*))/", $the_content, $matches, PREG_SET_ORDER );
This line searches for https://vimeo.com/XXXXXXXX, eight digits video id. When video id is shorter you must fill it with zeroes in leftmost positions: 1234567 -> 01234567.
