Patent ID: 7028096

Claim:
A method of caching in a system for transmitting a plurality of media data titles to one or more client(s) from a central server computer system and a proxy server computer system located in a computer network, said proxy server computer system located in the network between the central server computer system and the one or more client(s), wherein each media data title is divided into blocks to be transmitted to the one or more client(s) in a time sequence, and each block is divided into sub-blocks, comprising: causing the central server computer system to transmit data in the media data titles to the proxy server computer system via a backbone network connection, and the proxy server computer system to transmit data in the media data titles to one or more client(s) via a local network connection; identifying which sub-blocks from different blocks of each media data title that are to be cached, wherein the identified sub-blocks include some sub-blocks in each of the blocks of at least one media data title; caching only the identified sub-blocks at the proxy server computer system to reduce the transmission bit rate of the central server computer system in the network for transmitting data in the media data titles to the proxy server computer system; and combining sub-blocks of a media data title cached at the proxy server computer system with sub-blocks of the media data title not cached at the proxy server computer system and transmitted from the central server computer system to the proxy server computer system through the network, for delivery to the one or more client(s), wherein a peak transmission rate in the backbone network connection for the central server computer system to transmit data in the media data titles to the proxy server computer system is reduced; wherein the media data titles include video titles and the sub-blocks comprise partial information of video frames, wherein the video frames are to be transmitted sequentially wherein the combining combines the partial information of video frames from the proxy server computer system with complementary partial information of such video frames from the central server computer system into complete video frames and sending the complete video frames to the client(s); and wherein the partial information comprise video information obtained at a set of sampling times and at a first sampling rate lower than that of a video source from which said information originates, and wherein the combining combines the video information at the lower first sampling rate from the proxy server computer system with complementary video information taken at sampling times different from the set of sampling times of such video frames from the central server computer system into video data at a sampling rate higher than the first sampling rate and sending the video data at the higher sampling rate to the client(s).