Convert Images to Video Tool

We're in need of a tool which should be working as a service that's invoked to convert some images into video and post back the video url. This service should be running on the server and be available for a method call which sends an array of images url, loads them and convert them to video and then post back the video url. The output format we're after would be FLV (using FFMPEG) or other known video format. We're mostly interested in someone who done this before and would be only a matter of plug-in into the application as we're short in schedule.