Method and device for synthesizing three-dimensional background content

A method for synthesizing three-dimensional (3D) background content and application content by a device, the method comprising:

• receiving the application content from an external device connected to the device, wherein the application content comprises two dimensional (2D) non-stereoscopic content;
• generating output stereoscopic content by synthesizing the application content and the 3D background content including at least one of a 3D stereoscopic video and a 3D stereoscopic image;
• and
• transmitting the generated output stereoscopic content to the external device,
• wherein the generating of the output stereoscopic content comprises disposing the application content to be displayed in a first region of a display of the external device and disposing the 3D background content to be displayed in a second region of the display.