IMAGE DECODING APPARATUS, IMAGE DECODING METHOD, IMAGE DECODING PROGRAM, RECEIVING APPARATUS, RECEIVING METHOD AND RECEIVING PROGRAM

摘要

PROBLEM TO BE SOLVED: To reduce an encoding amount of quantization parameters so as to improve encoding efficiency.SOLUTION: An image decoding apparatus encodes an image and decodes a bit stream whose differential quantization parameter is encoded in a quantization encoding block unit that is a management unit for quantization parameter made by dividing the image. The image decoding apparatus comprises: a first encoded bit stream decoding unit 202 to decode a bit stream in the quantization decoding block unit and to extract a differential quantization parameter for a quantization decoding block of a decoding target; a prediction quantization parameter derivation unit 205 to derive a prediction quantization parameter using the quantization parameter of a plurality of quantization decoding blocks which precedes the quantization decoding block of the decoding target in decoding order; and a quantization parameter generation unit 203 to generate a quantization parameter for the quantization decoding block of the decoding target by addition of a differential quantization parameter for the quantization decoding block of the decoding target and the prediction quantization parameter.