Weighted prediction (WP) is a tool to compensate the brightness difference in video sequences with brightness variations. In this paper, some weight parameter determination methods are surveyed, and a weighted prediction algorithm together with the hardware architecture design is proposed. The main idea of the algorithm is to limit the number of weight parameters transmitted by quantizing the parameter into levels and using only offset as the parameter. As a result, the extra parameters sent in each slice header is thus limited by the number of levels, and the parameter determination process requires much less computations. By further utilizing sub-sampling of brightness levels and estimated offset sum, a simplified architecture is also proposed. Simulation result shows that the later architecture achieves a coding gain of about 0.5 dB over weighted prediction method in JM9.6 and has a minimum overhead to hardware implementation.