Patent ID: 7949048
Filing Date: 2011-05-24
Classification: H04N

Abstract:
1. A video decoding method for subjecting a to-be-decoded block of a to-be-decoded image to motion compensated prediction decoding, the method comprising: decoding encoded data of a to-be-decoded image to obtain a quantized orthogonal transform coefficient, motion vector information and index information; calculating a first distance between a first reference image designated by the index information and the to-be-decoded image, and a second distance between the first reference image and a second reference image designated by the index information; calculating a first weighting factor for the first reference image and a second weighting factor for the second reference image based on a ratio of the first distance to the second distance; generating a prediction image by calculating a linear sum of an image of a region specified by the motion vector information in the first reference image and an image of a region specified by the motion vector information in the second reference image; obtaining a prediction error by subjecting the quantized orthogonal transform coefficient information to inverse quantization and inverse orthogonal transform; and generating a reproduction image signal by adding the prediction error and the prediction image, wherein the calculating the first weighting factor sets values of both of the first weighting factor and the second weighting factor to a value for an average prediction if: (1) the second weighting factor is larger than an upper limit, or (2) the second weighting factor is smaller than a lower limit, or (3) the second distance is 0.