Power consumption of a decoder is reduced. The decoder includes an FPGA. The FPGA performs at least one processing to decode the data. In the case where the data has first resolution, an input data signal of the FPGA is a binary signal and a clock frequency of the FPGA is a first frequency. In the case where the resolution of the data is lower than the first resolution, the input data signal of the FPGA is a pulse signal and the FPGA operates at a second frequency which is lower than the first frequency. The FPGA operates at the first clock frequency in the case of decoding 8K data and the FPGA operates at the second clock frequency in the case of decoding 4K or 2K data.