Video encoding method and apparatus and video decoding method and apparatus

Abstract

A video encoding method includes extracting at least one reference macroblock from each of a plurality of reference frames to generate a plurality of reference macroblocks, computing a linear sum of the reference macroblocks using weighting factors to generate a predictive macroblock, generating a motion vector between the video macroblock and the reference macroblock corresponding to the predictive macroblock, generating a prediction error signal between the predictive macroblock and the video macroblock, and encoding the prediction error signal, a first index indicating the plurality of reference frames, a second index indicating the weighting factors and the motion vector.

1 . A video encoding method of performing a motion compensated prediction interframe encoding on a video macroblock of a video picture, using a plurality of reference pictures and a motion vector between the video macroblock and at least one reference picture, the method comprising: 
 determining at least one weighting factor and at least one DC offset value;    calculating a linear sum of a plurality of reference blocks extracted from the reference picture using weighting factors;    adding the linear sum and the DC offset value to generate a prediction block;    generating a prediction error signal between the prediction block and the video block; and    encoding information items indicating the prediction error signal, the reference picture, the weighting factor, the DC offset value and the motion vector,    wherein determining the weighting factor includes expressing and determining the weighting factor by a rational number using a denominator to be a power of 2 set for every video picture, and encoding the information items includes encoding information items of the denominator and the numerator of the rational number as information of the weighting factor.    
   
   
       2 . A video encoding apparatus configured to perform a motion compensated prediction interframe encoding on a video macroblock of a video picture, using a plurality of reference pictures and a motion vector between the video macroblock and at least one reference picture, the apparatus comprising: 
 a determining unit configured to determine at least one weighting factor and at least one DC offset value;    a calculator configured to calculate a linear sum of a plurality of reference blocks extracted from the reference picture using weighting factors;    an adder configured to add the linear sum and the DC offset value to generate a prediction block;    a generator configured to generate a prediction error signal between the prediction block and the video block; and    an encoder configured to encode information items indicating the prediction error signal, the reference picture, the weighting factor, the DC offset value and the motion vector,    wherein the determining unit includes a weighting factor unit configured to express and determine the weighting factor by a rational number using a denominator to be a power of 2 set for every video picture, and the encoder is configured to encode information items of the denominator and the numerator of the rational number as information of the weighting factor.