A data processing system includes a first virtual machine, a second virtual machine, a switching unit, an external data processing device, and a video output unit. The first virtual machine performs video processing on input processing data. The second virtual machine transmits/receives the processing data to/from an outside. The switching unit switches an input destination of the processing data from the first virtual machine to the second virtual machine. The external data processing device receives the processing data transmitted from the second virtual machine, performs the video processing on the processing data, and transmits the processing data to the second virtual machine. The video output unit outputs, to a video output device, the processing data on which the video processing has been performed by the first virtual machine, and outputs, to the video output device, the processing data that the second virtual machine has received.