copy videos from you tube and convert

hello friends. i want a Linux server based php script which is done some work automatically. i want add some youtube bulk watch url in it. script auto download videos from it in all formats which available on youtube. like mp4 1080p, 720p, 480p, 360p, 240p, 3gp 240p, 144p mp3 320, 128, 48kbps after download these formats from one video add in it my site watermark. i want if need video convert then script auto detect video conversion settings not size or quality lose. i tell about my site in inbox its already work like smiler but in it i need currently convert videos manually. after done all things script move video to other server direct download like. i use for my site 4 server for load balancing. if need run script with admin panel no problem. i want plz BID only who is really understand what m want and able to make this script. or do any same type work already. need done php script, templates, some other user friendly features.