Multi-mode printing control system

1. Field of the Invention An apparatus and a method for generating and outputting image data. The method and apparatus includes inputting information output from an external apparatus, judging whether or not the inputted information includes specific control data, and controlling switching between a plurality of modes based on whether the inputted information includes the specific control data. The plurality of modes including a first mode in which the image data is converted into a video signal in parallel with description processing of the image data and a second mode in which the image data is converted into the video signal after the description processing of one page of the image data is performed.