To provide the audio and/or video program of a higher quality version progressively through a client server based network.

In response to a user command for browsing a specific program, a client requests hierarchic data related to that program to the server. Based on a bandwidth available on the network, the number of continuous layers to be transmitted is also specified. Subsequently, data is received from the server, cached and rendered upon reception before being presented to a browser. Upon receiving a request for a higher quality version from the user, enhance layers related to the program are requested as much as possible using the available bandwidth. Requested data is received and combined with lower layer data stored previously and the program of a higher quality version is rendered and a new version is presented to the user.