Video file convertor with watch folder

I need a application that runs in the background, and watches a folder, or a group of folders that can convert video files. The app must do the following: - the application must work on a windows platform (bonus money for a version that works on Linux and Mac this can be arranged with the programmer for how much) - convert all video formats to any other video format (for windows media files, a .prx file must be able to be used for setting encoding profile) - watch a folder, or groups of folders, including sub folders - run in the background and automatically see/check for new files and Que/start converting them and output the converted file to a specific folder - email a list of new files found, which files have been converted, and which are still left in the Que