MOTION ESTIMATION METHOD USING ADAPTIVE MODE DECISION

A motion estimation method using adaptive mode decision is disclosed. The method includes a motion vector difference value calculation step of calculating a motion vector difference value using an input motion vector estimation value x component for a current block and an input x offset corresponding to a current SAD. At the MVD Variable Length Coding (VLC) step, the length of a bit string, which is obtained by performing variable-length coding on an MVDx, is calculated. At a motion vector difference value calculation step, a motion vector difference value is calculated using an input motion vector estimation value y component for a current block and an input y offset corresponding to the current SAD. At an MVD VLC step, the length of a bit string, which is obtained by performing variable-length coding on an MVDy, is calculated. Thereafter, the amount of motion vector coding is produced by adding the MVDx and the MVDy. The amount of texture coding of a current block or a macro block is estimated using SAD values and quantization coefficients of previous macro blocks. A SAD correction coefficient is produced using the amount of motion vector coding and the texture vector coding amount. Finally, the SAD values are multiplied by the SAD correction coefficient, thus correcting the SAD values.