Patent ID: 8682090

Claim:
An image information decoding apparatus, comprising: a processor; an inverse quantization unit configured by the processor to: perform an inverse quantization of an encoded image in accordance with an inverse quantization scaling factor, the encoded image corresponding to a chroma signal; and generate inverse quantization coefficients corresponding to the chroma signal; an inverse transformation unit configured by the processor to perform an inverse transformation of the inverse quantized coefficients and generate a decoded image corresponding to the chroma signal based on an output of the inverse transformation; and an intra-image prediction unit configured by the processor to: perform intra prediction of the decoded image in an intra DC prediction mode; and generate, when the chroma signal format has a 4:4:4 format, a prediction image corresponding to the chroma signal by: dividing a block of 16×16 pixels into four unit blocks of 8×8 pixels arranged in longitudinal and lateral directions within the block of 16×16 pixels; and calculating, for each of the unit blocks of 8×8 pixels, mean pixel values using pixel values of vertical and horizontal pixels disposed adjacent to the block of 16×16 pixels, wherein the inverse quantization unit is further configured by the processor to determine the inverse quantization scaling factor based on a normalization coefficient of the inverse transformation and a block size of the inverse transformation.