Modification done to the code of a single page that coninuosly plays alternating live video feeds and recorded videos

I have a single html page that is an art project. The site plays videos which are meant to act like movie. The videos are a mix of live video streams from IP cameras and also recorded video. The live stream videos also play have a recorded audio file that plays along with them. Here is my problem : when an IP camera is down but the url still exists it will still load and play as a black image. I would like my page to detect if the camera is down or is blacked out and then play an alternate feed or video. Here is my url so you can see what I am dealing with. [login to view URL]