Image encoding apparatus for determining quantization parameter, image encoding method, and program

Abstract

An amount of code is reduced for blocks in which visible degradation is not easily susceptible, while a large amount of code is assigned to blocks whose degradation in image quality is easily perceptible thereby suppressing the number of blocks for which a process is performed to achieve high quality image and thus suppressing an increase in the total amount of code. An input image is encoded in units of blocks. A block evaluation value for the block is calculated. The block is divided into N sub-blocks where N is equal to or greater than 2, and a sub-block evaluation value is calculated for each sub-block. A quantization parameter for the block is controlled based on the block evaluation value and the sub-block evaluation values.