IMAGE DECODER, IMAGE DECODING METHOD, AND IMAGE DECODING PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an image decoder which can decode the code data of image size larger than specified without changing an image memory and a decoded image display. SOLUTION: An image decoder computes a motion vector by a motion vector computer 18 (S14) if it is a macro block for coding between frames, and converts it to its quarter by a motion vector 1/4 converter 17 (S15). It takes out a quarter estimated reference image from a recomposed image (S16), based on the converted quarter motion vector by a reference image quarter intake part 16, and magnifies it to four times by an QCIF→CIF magnifier 14 (S17). It generates a recomposed image by adding a quadrupled estimated reference image to a decoded image after finish of reverse DCT conversion (S18). It scales down the image data again from the CIF size to QCIF size and stores it in an image memory 11 (S10), and displays the scaled-down image on a decoded image display 13 (S11 and S12).