<p>An audio decoding apparatus is provided for receiving a bit stream on a block-by-block basis, decoding one block of the bit stream to form decoded audio data for a plurality of channels, and storing the decoded audio data for each of the plurality of channels in a memory device, thereby down-mixing the decoded audio data for each of the plurality of channels. The audio decoding apparatus includes an operation section for down-mixing the decoded audio data for each of the plurality of channels corresponding to a first block of the bit stream in the memory section while a second block of the bit stream is decoded. <IMAGE></p>