Patent ID: 8249373

Claim:
An image decoding apparatus comprising: a memory; a detecting part which receives data of a plurality of macroblocks included in an image and detects whether or not a first macroblock included in the plurality of macroblocks has an intra-block; and a control part which writes a DCT coefficient of the first macroblock into the memory when the detecting part determines that the first macroblock has the intra-block, and does not write the DCT coefficient of the first macroblock into the memory when the detecting part determines that the first macroblock has no intra-block, wherein a flag indicating that the DCT coefficient of a third macroblock adjacent to the upper side of the first macroblock in the image is used in the decoding of the first macroblock is set when detecting that the third macro block is the intra-block and the first block is provided in the lower side of the third block, and wherein the control part uses the DCT coefficient of the third macroblock in the decoding of the first macroblock when detecting that the flag is set and the control part does not use the DCT coefficient of the third macroblock in the decoding of the first macroblock when detecting the flag is not set.