H.263-based SNR scalable video codec

We propose a H.263-based video coder with two-layer SNR scalability. The base layer is coded by using the default H.263 coding algorithms to achieve high compressed video data and the enhanced layer is coded by advanced coding such as HVS-based quantization updating. The enhanced layer contains only coded refinement data for the DCT coefficients of the base layer. Bitstream syntax and semantics for enhancement layer are designed and quantizer design using the HVS is proposed. Data from the two layers are combined after inverse quantization processes and inverse DCT coefficients by adding in the decoder.