Patent ID: 8681869

Claim:
A method for measuring distortion of a current block of an input video signal, used to estimate motion by estimating high-frequency and low-frequency components of the current block, the method applied to a video encoder and a video decoder, the method comprising: calculating the sum of distortion values of the high-frequency component of the current block using a value obtained by subtracting pixel values of reference blocks of the current block and a difference value between mean values of the current and reference blocks from pixel values of the current block; calculating the sum of first distortion values of the low-frequency component of the current block using the pixel values of the current block and the pixel values of the reference blocks of the current block; calculating a second distortion value of the low-frequency component of the current block by multiplying the sum of the distortion values of the low-frequency component of the current block by an efficiency value of the low-frequency component estimation of the current block; adding the sum of the distortion values of the high-frequency component of the current block and the second distortion value of the low-frequency component of the current block; comparing a first rate-distortion cost obtained when a determined reference block is offset by a compensated value of the estimated low-frequency component with a second rate-distortion cost obtained when the determined reference block is not offset by the compensated value of the estimated low-frequency component; wherein when the first rate-distortion cost is less than the second rate-distortion cost, the compensated value of the estimated low-frequency component is added to the determined reference block, and when the first rate-distortion cost is greater than the second rate-distortion cost, the compensated value of the estimated low-frequency component is not added to the determined reference block; and generating a residual signal of the current block.