A system for performing high efficiency coding of an image signal includes a differential signal generating section, a processing section, a supply section, a coefficient train outputting section, and a code assigning section. The differential signal generating section generates a differential image signal between a current image signal inputted thereto and a prediction image signal inputted thereto for the current image signal with respect to a target block. The current image signal and the differential image signal each include a plurality of blocks and the target block is one of the plurality of blocks. The processing section executes processing of a one-dimensional orthogonal transform and a quantization for an inputted objective image signal, with respect to the target block, to generate the processing result as quantization coefficients. The supply section supplies the processing section with the differential image signal as the objective image signal with respect to the target block. The coefficient train outputting section generates a quantization coefficient train from the quantization coefficients. The code assigning section assigns a code to each quantization coefficient of the train to generate a transmission signal.