Because there are many formats in video signals, it is hard to exchange information among them. It could be solved by the technologies, such as video format conversion. Based on discussing the algorithms of video format conversion, two algorithms with good effects, which are convenient for hardware implementation, are proposed. They are windowed function(with enhanced edge) algorithm and median filtering(with enhanced edge) algorithm. The first algorithm is simulated by software and tested on the FPGA board, and the results prove that the image has good quality and strong robustness. The second algorithm, by using the correlative information of space and time of the signal, also made the image get good quality with a sharper edge and lower hardware cost. Both algorithms have great practical value.