I. Introduction
Aseries of nonscalable hybrid video coders such as MPEG-x and H.26x has been successfully developed. The latest video coding standard H.264/AVC [1] jointly developed by ISO and ITU provides more than 50% bitrate saving against MPEG-2 video coding standard [2] at the same quality and also contains many network-friendly features. However, the generated nonscalable bitstream cannot adapt to video transmission well on time-varying networks including wireless and cable channels or terminal devices with different processing capabilities regarding available memory, computation power and accessible bandwidth etc. Scalable video coding is more effective to address these situations since its generated bitstream is decodable at different bit-rates which may have different quality levels, temporal or spatial resolutions etc.