Sub-band coding has been investigated for the novel application of video transmission over packet-switched networks. The scheme, which divides the input signal into frequency bands in all three dimensions, seems promising in that it lends itself to parallel implementation, it is robust enough to handle errors due to lost packets; and it yields high compression with sustained good quality. Moreover, it may be well integrated with the network to handle issues like flow-control and error-handling. The article presents the underlying design goals together with a software implementation and associated results.