Today the problem of transmitting data over heterogeneous networks has received considerable attention. In this paper we propose the design of a system to transmit in realtime high-quality video signal over Internet. To do that, we present a Multiple Description (MD) coding based on polyphase down sampling algorithm that splits an image source in an arbitrary number of balanced descriptions. Our goal is to obtain both the best reconstruction quality from the received descriptions (also only one) and a subjective indistinguishable reconstruction from the original, if all the descriptions are available.