Scalable video delivery to unicast handheld-based clients

This paper discusses the proxy gateway and unicast client of a scalable video delivery system. The aim is to deliver video to heterogeneous clients using only a single video stream. This is possible using a layered wavelet-based codec that allows a video stream to be encoded and divided, and is then distributed using several multicast channels. A layered multicast method of delivery allows each client to control the amount of video information it receives, and hence the video quality, without the server having to transcode or modify the video stream. However, because there are devices that cannot receive multicast data, e.g., handheld devices or PDAs, a proxy gateway was developed to receive the multicast stream and retransmit them in a unicast manner The proxy gateway, designed primarily to support the low-powered handheld devices, also performs buffering and other actions that may require amounts of memory that handheld devices do not have. This complete system is now in its final stage of development and the performance of the proxy gateway and unicast handheld-based client have been tested.