| CPC H04N 19/513 (2014.11) [H04N 19/139 (2014.11); H04N 19/176 (2014.11)] | 12 Claims |

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1. A method for motion estimation, comprising:
searching for a start search point in a target macroblock to obtain a start search point;
when it is determined, according to a cost value of the start search point, that early termination is not performed, determining a first search range according to a motion vector of a previous frame of a target position in the target macroblock;
performing an asymmetrical cross search according to the first search range to obtain a first target search point;
when it is determined, according to the cost value of the start search point and a cost value of the first target search point, that early termination is not performed, performing rectangular window full search to obtain a second target search point;
when it is determined, according to the cost value of the start search point and a cost value of the second target search point, that early termination is not performed, determining a second search range according to the motion vector of the previous frame of the target position in the target macroblock and a motion vector of previous two frames of the target position in the macroblock;
performing extended multi-level hexagonal grid search according to the second search range, to obtain a third target search point;
when it is determined, according to the cost value of the start search point and a cost value of the third target search point, that early termination is not performed, performing extended hexagonal search to obtain a fourth target search point; and
determining a motion vector of the target macroblock according to the fourth target search point.
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