Two-layer encoding for hybrid high-definition DVD

A hybrid high-definition encoder and method are disclosed, for processing signal data as a plurality of block transform coefficients for each of base layer data and enhancement layer data, where the encoder includes a two-layer decomposition unit for decomposing an original high-definition signal data sequence into base layer data and enhancement layer data, a standard-definition encoder coupled to the decomposition unit for encoding the base layer data as a base layer bitstream embodying a standard-definition data sequence, and a high-definition encoder coupled to the decomposition unit and the standard-definition encoder for encoding only the difference between the high-definition data and the standard-definition data as base layer picture user data embodying a high-definition data sequence.