Patent ID: 7161983

Claim:
A video encoder for motion compensated encoding of video data comprising: means for generating a first motion vector for a first image segment S K of a current frame to be encoded, based on a reference frame; motion field encoding means for representing the first motion vector as a first motion coefficient vector c K comprising a first set of absolute motion coefficients c i , such that c i ·f i (x,y) represents an approximation of the first motion vector, f i (x,y) defines a set of basis functions and i is an index that defines correspondences between particular basis functions and absolute motion coefficients c i ; means for generating a second motion vector for a second image segment S L of the current frame to be subsequently encoded, based on the reference frame; motion field encoding means for representing the second motion vector as a second motion coefficient vector c L comprising a second set of absolute motion coefficients c j , such that c j ·f j (x,y) represents an approximation of the second motion vector, f j (x,y) defines a set of basis functions and j is an index that defines correspondences between particular basis functions and absolute motion coefficients c j ; motion coefficient prediction means for predicting a predicted motion coefficient vector p L for the second image segment S L , the predicted motion coefficient vector p L comprising a set of predicted motion coefficients p j , based upon the previously generated first motion coefficient vector c K ; means for representing each of the absolute motion coefficients c j of the second set of absolute motion coefficients as a sum of a corresponding predicted motion coefficient p j and refinement motion coefficient r j , where each of the refinement motion coefficients r j represents the difference between one of the absolute motion coefficients c j and the corresponding predicted motion coefficient p j ; means for representing the second motion coefficient vector c L as a vector r L of refinement motion coefficients r j .