Patent ID: 8582649

Claim:
An encoding device which performs image compression with differential encoding, the encoding device comprising: a computer configured to provided: a calculation result storage unit being adapted to store information based on results of a differential calculation of the differential encoding along with information on reference pictures used for the differential calculation; a determination unit which determines, from the information based on results and the information on reference pictures stored in the calculation result storage unit, whether or not the differential calculation has been performed on a reference picture for the differential calculation of a target picture undergoing the image compression, wherein a determination by the determination unit that the differential calculation has been performed thereby indicates that information based on a result of the differential calculation of the target picture is stored in the calculation result storage unit; and a differential encoding unit which when it is determined by the determination unit that the differential calculation has been performed, reads, from the calculation result storage unit, the information based on the result of the differential calculation of the target picture stored in the calculation result storage unit instead of recalculating the differential calculation of the target picture, and outputs a result in accordance with the information read from the calculation result storage unit, and when it is determined by the determination unit that the differential calculation has not been performed, performs the differential calculation of the target picture, and outputs a result based on the performed differential calculation.