Patent ID: 7237032

Claim:
computer-implemented process for obtaining progressively higher quality versions of an audio-only program, video-only program, or audio and video program over a client-server based network, comprising a client computer performing the process actions of: requesting a base quality version of the program from a server over the network, wherein the base quality version of the program comprises layer data of a layered unicast having hierarchically related layers in that the lowest level layer is a base layer and each subsequently higher level layer adds enhancing information for enhancing the quality of the program that can be rendered from the layers preceding it in the hierarchy, and wherein requesting a base quality version of the program from a server over the network comprises requesting as many layers, in the order of their position in the hierarchy starting with the base layer, as can be transmitted from the server to the client without exceeding the available bandwidth of the network; receiving and caching the requested layer data associated with the base quality version of the program; requesting at least one enhancement layer of the layered unicast from the server over the network; receiving and caching the requested enhancement layer data; and combining the requested enhancement layer data with the previously cached layer data associated with the base quality version of the program as it is received to produce a higher quality version of the program.