1. A broadcasting signal processing apparatus comprising: a signal receiver which receives a broadcasting signal, the broadcast signal including an application program for providing broadcasting information; a signal processor which processes the broadcasting signal so that a video is displayed based on the broadcasting signal received by the signal receiver; and a controller which controls the signal processor so that, if an adjustment condition of the video being displayed is satisfied while the application program is executed, execution of the application program is paused without terminating the application program and the video being displayed is adjusted while the application program is paused, wherein the application program comprises a graphic user interface (GUI), and the application program displays the broadcasting information through providing the GUI on a display, the GUI provided by the application program is displayed simultaneously with the video while the application program is executed, and the GUI of the application program is not displayed while the application program is paused, and the controller changes a current state of the application program from an execution state to a pause state by calling a function of the application program that pauses the execution of the application program.