Display apparatus, image processing system, display method and image processing method

PURPOSE: A display device, an image processing system, a display method, and an image processing method are provided to enable a plurality of user to watch each of the different contents through one display device or to enable to easily check the contents in which other user is watching. CONSTITUTION: An output unit (130) is operated in a first mode, which displays only in an image frame of one contents which is outputted from the signal processing units (120-1~120-n) through a display unit, or in a second mode, which combines and displays an image frame of each of the contents which is outputted from the signal processing units through the display unit. A control unit (160) controls the output unit according to the operation status of a video call processing unit (190) and decides the combination of the image frame of each of the contents which is outputted from the signal processing units. [Reference numerals] (110) Receiving unit; (120) Signal processing unit; (130) Output unit; (140) Synchronization signal generating unit; (150) Interface unit; (160) Control unit; (190) Video call processing unit