IMAGE DECODING DEVICE, IMAGE DECODING METHOD, IMAGE DECODING PROGRAM, RECEPTION DEVICE, RECEPTION METHOD AND RECEPTION PROGRAM

摘要

PROBLEM TO BE SOLVED: To improve encoding efficiency by reducing a code amount of a quantization parameter.SOLUTION: An image decoding device encodes an image and decodes a bit stream for which a differential quantization parameter is encoded for the unit of a quantization decoding block that is a management unit of a quantization parameter obtained by dividing the image. In the image decoding device, a first encoded bit stream decoding part 202 decodes the bit stream for the unit of a quantization decoding block and extracts a differential quantization parameter of the quantization decoding block subjected to decoding. A predictive quantization parameter derivation part 205 derives a predictive quantization parameter by using quantization parameters of a plurality of quantization decoding blocks that are preceding to the quantization decoding block subjected to decoding, in the order of decoding. A quantization parameter generation part 203 generates a quantization parameter of the quantization decoding block subjected to decoding by adding the differential quantization parameter of the quantization decoding block subjected to decoding and the predictive quantization parameter.SELECTED DRAWING: Figure 2