Create PHP script creating caps from videos

Hello, I'm currently developing a video management platform for private use based on php. I've git a player that is capable of displaying thumbnails for preview purposes when I hover the payers track at any position but I need to provide a sprite image of screencaps of the video in order to use that feature. As I don't have much experience in that context I'm looking for someone who is capable of creating a php code that is creating caps from a bunch of videos whose URL I store in a database. Then compile all caps of one video into a single sprite image and implement it in the jwPlayer I'm using. Please use the word caps in your bid to show that you've read the requirements before you post.