Abstract: A method for fast multiple reference frame motion estimation, which is used to perform motion estimation between a current frame and reference frames Fn?1, Fn?2, . . . , Fn?k. The method performs a special block matching to find a plurality of motion vectors for blocks of each frame with respective to a previous frame and then composes motion vector(s) of the current frame referring to the reference frame Fn?(k?1) and a motion vector of the reference frame Fn?(k?1) referring to the reference frame Fn?k into composed motion vectors of the current frame referring to the reference frame Fn?k for the block in the current frame. The method selects a composed motion vector with a minimum of cost function from the composed motion vectors produced when composing the motion vectors and then finely adjusts the composed motion vector selected, thereby obtaining an adjusted motion vector.

Abstract: A method for fast macroblock mode decision is disclosed. The method includes: (A) determining if a motion cost at the origin (0, 0) or a prediction motion vector (PMV) for a 4n*4n macroblock is smaller than a first threshold; (B) if the motion cost is smaller than the first threshold, determining a macroblock mode as 4n*4n and ending the method; (C) if the motion cost is not smaller than the first threshold, using an adaptive diversity search strategy to perform motion estimation on four 2n*2n blocks associated with the 4n*4n macroblock; (D) determining if all motion costs of the four 2n*2n blocks in step (C) are smaller than a second threshold; and (E) if step (D) determines that the motion costs of the four 2n*2n blocks are smaller than the second threshold, determining the macroblock mode as 2n*2n and ending the method.

Abstract: A method for fast macroblock mode decision is disclosed. The method includes: (A) determining if a motion cost at the origin (0, 0) or a prediction motion vector (PMV) for a 4n*4n macroblock is smaller than a first threshold; (B) if the motion cost is smaller than the first threshold, determining a macroblock mode as 4n*4n and ending the method; (C) if the motion cost is not smaller than the first threshold, using an adaptive diversity search strategy to perform motion estimation on four 2n*2n blocks associated with the 4n*4n macroblock; (D) determining if all motion costs of the four 2n*2n blocks in step (C) are smaller than a second threshold; and (E) if step (D) determines that the motion costs of the four 2n*2n blocks are smaller than the second threshold, determining the macroblock mode as 2n*2n and ending the method.

Abstract: A method for fast multiple reference frame motion estimation, which is used to perform motion estimation between a current frame and reference frames Fn?1, Fn?2, . . . , Fn?k. The method performs a special block matching to find a plurality of motion vectors for blocks of each frame with respective to a previous frame and then composes motion vector(s) of the current frame referring to the reference frame Fn?(k?1) and a motion vector of the reference frame Fn?(k?1) referring to the reference frame Fn?k into composed motion vectors of the current frame referring to the reference frame Fn?k for the block in the current frame. The method selects a composed motion vector with a minimum of cost function from the composed motion vectors produced when composing the motion vectors and then finely adjusts the composed motion vector selected, thereby obtaining an adjusted motion vector.