Multi-resolution shape coding algorithm for MPEG-4

The MPEG-4 visual standard is developed to provide users a new level of interaction with visual contents. It is the first international standard allowing for transmitting arbitrarily shaped video objects and provides technologies to view, access and manipulate objects rather than pixels. MPEG-4 scalability features enable the content providers to transmit the same content through channels with variable bandwidths. In this paper, we propose a new coding technique employing quadtree-based decomposition to obtain a shape representation at different resolution levels. Fewer bits coding the shape can be sent on a bandwidth-limited channel while sacrificing the resolution. This is convenient for browsing applications or viewing a high-resolution image on a lower-resolution display device. The proposed scheme can improve coding efficiency and get a good tradeoff between bit-rate and distortion. The method is shown to be simple, efficient solution and suitable for hardware implementation.