Due to the real-time characteristic

live streaming applications attract more and more attentions.Most existing live streaming applications provide streaming clients with the same data at the same time

which do not match with each user's requirement.In this paper

a novel software architecture is proposed which can be used to implement a time-shifting live streaming system.Besides

this paper also proposes a novel algorithm to calculate the play time for the time-shifting system.At last

a system based on the proposed architecture and algorithm has been developed and deployed successfully in Shanghai Daning IPTV(internet-protocol television) systems.