Patent ID: 8165458

Claim:
A playback device comprising: a reading unit operable to read an application program, image data, a video stream, and an application management file from a recording medium; a virtual machine unit operable to execute the application program; a memory unit including an image data area for storing the image data; a playback unit operable to play back video data with use of the image data and the video stream in accordance with the application program; a management unit operable to, in accordance with the application management file, instruct the virtual machine unit to start and terminate the application program, and instruct the memory unit to change the image data area, the management unit further operable to cause the virtual machine unit to forcibly terminate the application program before instructing the memory unit to change the image data area even when the application management file specifies the continuous execution of the application program; the playback device further comprising a network interface unit operable to download data of a browser screen from a server device on an external network, wherein the playback unit is operable in a live playback mode to synthesize the browser screen with a video image played back from the recording medium, and the changing of the image data area includes one of allocating a cache area in the image data area and freeing the cache area from the image data area, the cache area being for temporarily storing data of a current browser screen and a previous browser screen; wherein, when the image data includes left-view image data and right-view image data for a 3D menu, the changing of the image data area includes freeing the cache area from the image data area and using a free area available by freeing the cache area to store the left-view image data and the right-view image data; and wherein the management unit, in accordance with the application program, accepts from a user an instruction specifying whether or not the 3D menu should be played back, causes the virtual machine unit to check a capacity of the memory unit when the instruction specifies that the 3D menu should be played back, provides the memory unit with an instruction when the capacity of the memory unit is larger than a predetermined threshold value, the instruction being to free the cache area and use the free area to store the left-view image data and the right-view image data, and disables playback of the 3D menu when the capacity of the memory unit is smaller than the predetermined threshold value.