Patent ID: 7912301

Claim:
An image information decoding apparatus for performing inverse quantization and inverse orthogonal transformation to image compressed information on a block basis, the image information decoding apparatus comprising: decoding means for decoding quantized and encoded transform coefficients, a chroma format signal indicating resolution of a color signal, and a color space signal indicating color space; inverse quantization means for adaptively changing inverse quantization technique in accordance with the chroma format signal and the color space signal to inverse-quantize the transform coefficients; inverse transformation means for performing inverse integral transformation of the inverse-quantized transform coefficients; and intra-image prediction means for generating a prediction image of the color signal at a block size corresponding to the chroma format signal and the color space signal by using an output signal from the inverse transform means; wherein the chroma format signal at least includes 4:2:0 format, 4:2:2 format, and 4:4:4 format, and the color space signal at least includes YCbCr, RGB, and XYZ, and when the chroma format signal is 4:2:0 format and the color space signal is YCbCr, the block size is adaptively changed and the prediction image is generated on an 8×8 pixel basis, when the chroma format signal is 4:2:2 format and the color space signal is YCbCr, the block size is adaptively changed and the prediction image is generated on an 8×16 pixel basis in which blocks of 8×8 pixels are arranged in a longitudinal direction, and when the chroma format signal is 4:4:4 format and the color space signal is YCbCr, RGB, or XYZ, the block size is adaptively changed and the prediction image is generated on a 16×16 pixel basis in which blocks of 8×8 pixels are arranged in longitudinal and lateral directions.