Technical backgrounder-hierarchical vector quantization

The hierarchical vector quantization (HVQ) image-compression technology significantly advances the state-of-the-art of motion video transmission for two-way video-conferencing. HVQ technology provides approximately a 70% improvement in transmission efficiency over motion-compensated transform algorithm, the most advanced image-compression technology in the world prior to HVQ. In order to show how the HVQ works, the author describes the compression techniques that preceded it. It is concluded that HVQ greatly improves upon transform coding, significantly enhancing image quality by eliminating the artifacts and other image distortions inherent in transform coding