Moving image data editing apparatus, moving image data reproducing apparatus, moving image data editing method, and moving image data reproducing method

This invention is directed to the provision of a moving image data editing apparatus 1 for applying masking to a portion of an image by editing moving image data in which each frame is divided into pixel blocks of a predetermined size and encoded on a pixel block basis. Moving image data editing apparatus 1 comprises: pixel block extracting means 11 for extracting from an input data stream of moving image data 71 pixel blocks BL2 and BL4 that are located within the region 72 to which masking is to be applied; fixed pattern inserting means 12 for inserting precoded fixed pattern data 73 into the original positions of extracted pixel blocks BL2 and BL4 in the data stream; and pixel block inserting means 13 for inserting extracted pixel blocks BL2 and BL4 as user data into the data stream.