Patent ID: 7161982

Claim:
A motion video encoding device which adaptively selects and uses intra-frame encoding or inter-frame prediction encoding for encoding each block as an encoding unit, comprising: frame memory means for storing an input image and a reference image as the result of decoding of a frame before; block encoding means for referring to the input image stored in the frame memory means and carrying out a block encoding process for each block of the input image according to a selected encoding mode and a quantization step designating the width of quantization of image data and thereby generating coded data; code counting means for monitoring the coded data and thereby counting the code volume from the latest synchronization code pattern inserted in the coded data to coded data of a block that has been encoded latest; code volume control means for referring to the code volume of the coded data outputted by the block encoding means and a pixel value distribution statistic obtained by analyzing the input image and the reference image stored in the frame memory means, thereby calculating the quantization step for each block and for each selectable encoding mode so that image distortion caused by the block encoding process will be minimum, and outputting a code volume predicted value assigned to a target block which will be encoded next, under the condition that the code volume for a frame should be a preset volume or less; data loss probability estimation means for estimating the probability that data loss will occur to the target block due to transmission error, based on the code volume predicted value assigned to the target block, the code volume counted by the code counting means, and a preset error probability per bit; frame coding distortion estimation means for estimating frame coding distortion as image distortion caused by the block encoding processes for the frame, by referring to the pixel value distribution statistic of the input image obtained by the code volume control means; degradation power calculation means for calculating degradation power as error power between the input image and a decoded image assuming that data loss occurred to the target block during data transmission of the coded data, by use of the input image or the reference image stored in the frame memory means; degradation estimation calculation means for calculating a degradation estimation as an expected value of image degradation occurring to the target block due to data loss caused by transmission error, for each block and for each selectable encoding mode, based on the degradation power calculated by the degradation power calculation means and the data loss probability estimated by the data loss probability estimation means; and mode selection means for selecting an optimum encoding mode for the target block by referring to the degradation estimation calculated by the degradation estimation calculation means and the frame coding distortion estimated by the frame coding distortion estimation means.