To prevent or reduce deterioration of image quality caused by coding even if an abrupt luminance change occurs with flash or the like.

An image coding apparatus encodes image data by intra-encoding and inter-encoding. The apparatus comprises coding units (108, 115) configured to encode each picture in picture data for a first block, a luminance change detecting unit (105) configured to detect a luminance change for each picture and to detect a block affected by the luminance change, and code amount adjustment means (117, 118) configured to increase an amount of code allocated to the first block if the first block corresponds to the block affected by the luminance change, based on the result of detection in the luminance change detecting unit.

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