Patent ID: 8306386

Claim:
A playback device comprising: a memory having memory areas for a video plane for storing a moving image, an image plane for storing a GUI image to be displayed as a GUI, and a still plane for storing a background image; a moving image writer operable to write the moving image onto the video plane; a GUI image writer operable to write the GUI image onto the image plane; a background image writer operable to write the background image onto the still plane; a composite outputter operable to (a) read the moving image written onto the video plane and the GUI image written onto the image plane without reading the background image written onto the still plane if the moving image has a predetermined size sufficient to cover the whole background image, and read the moving image written onto the video plane, the GUI image written onto the image plane, and the background image written onto the still plane if the moving image does not have the predetermined size, (b) combine the read images by overlaying to generate a composite image, and (c) output an image signal representing the composite image; and a virtual machine operable to execute an application obtained from a source outside of the playback device, the application outputting an image using the moving image and configured to issue an instruction controlling the moving image to be displayed either as a full screen display or as a scaled-down screen display, wherein the predetermined size is a size of the moving image written onto the video plane, and the composite outputter reads the background image written onto the still plane if the application executed by the virtual machine issues a scaling-down instruction for the video plane that stores the moving image displayed as a full screen, and does not read the background image written onto the still plane if the application does not issue the scaling-down instruction, wherein the composite outputter, the moving image writer, the GUI image writer, and the background image writer share a memory bus connected to the memory unit, and the GUI image writer uses, if the composite outputter does not read the background image stored on the still plane, a time or a band of the memory bus allocated to the reading of the background image from the still plane, for writing the GUI image onto the image plane.