Patent ID: 7885332
Filing Date: 2011-02-08
Classification: H04N

Abstract:
1. A video encoding method for subjecting a to-be-encoded block of an input image to motion compensated prediction encoding with reference to a first reference image and a second reference image, comprising: calculating (A) a first distance between the first reference image and the input image and (B) a second distance between the first reference image and the second reference image; 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; obtaining a pixel value of a prediction image by calculating a linear sum of a pixel value of the first reference image and a pixel value of the second reference image according to the first weighting factor and the second weighting factor; generating a prediction error representing an error of the prediction image with respect to the to-be-encoded block; and encoding quantized orthogonal transform coefficient information obtained by the prediction error to orthogonal transform and quantization; wherein the calculating the first and second weighting factors 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, or (4) at least one of the first image and the second image is a long term reference image.