An active router architecture for multicast video distribution

Video distribution over the Internet poses many challenges. Due to the best-effort nature of today´s public data networks, end system applications cannot rely on either bandwidth or delay guarantees. We designed and implemented a prototype of a multicast video distribution architecture involving knowledgeable active routers, a scalable video codec based on the wavelet transformation, and a high-performance video scaling algorithm implemented as a router plug-in. The plug-in scales the video with an average overhead of only 22 μs per video datagram and is installed on-the-fly on the routers after the sender starts transmitting video for the first time. Through experiments on our test network, we show that we can dramatically improve the video quality on the receivers (up to 15 dB PSNR) by scaling the video on the routers to almost any target bandwidth. The target bandwidth is evaluated by the router solely based on monitoring of the load situation of the router´s downstream links and can be adjusted within 50 ms