Patent ID: 7492950

Claim:
An image information encoding apparatus for performing orthogonal transformation of an input image signal on a block basis for quantization, the image information encoding apparatus comprising: intra-image prediction means for adaptively changing block size used for prediction based on a chroma format signal indicating resolution of a color signal and a color space signal indicating color space for generating a prediction image for the input image signal; transformation means for performing, on a predetermined block size basis, integral transformation of a difference signal between the prediction image generated by the intra-image prediction means and an original image, and for generating transform coefficients; quantization means for adaptively changing quantization technique in accordance with transformation processing by the transformation means to quantize the transform coefficients; and encoding means for encoding the quantized transform coefficients, the chroma format signal, and the color space signal; 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 intra-image prediction means adaptively changes the block size and generates the prediction image on an 8×8 pixel basis, when the chroma format signal is 4:2:2 format and the color space signal is YCbCr, the intra-image prediction means adaptively changes the block size and generates the prediction image 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 intra-image prediction means adaptively changes the block size and generates the prediction image on a 16×16 pixel basis in which blocks of 8×8 pixels are arranged in longitudinal and lateral directions.