Patent ID: 8259123
Filing Date: 2012-09-04
Classification: H04N

Abstract:
1. An image processing apparatus for processing compression encoded data of a moving picture and outputting image data divided into a plurality of frames for displaying of the moving picture on a display device, the image processing apparatus comprising: a compressed moving picture memory that stores the compression encoded data of the moving picture; a work memory that is rewriteable; a decoding section that uses a storage area of the work memory as a ring buffer composed of a plurality of frame buffers, each for storing image data of one frame, that executes a decoding process on the compression encoded data of the moving picture stored in the compressed moving picture memory while selecting one of the frame buffers of the ring buffer in a circular manner, and that stores the image data that is a decoding result of the compression encoded data of the moving picture in the selected frame buffer; a frame memory that stores image data to be displayed on the display device; a controller that outputs a decoding command to the decoding section to initiate the decoding process of the compression encoded data of the moving picture stored in the compressed moving picture memory, and that outputs a drawing command involving designation of a frame buffer among the frame buffers of the ring buffer, the designated frame buffer storing the image data to be subjected to a drawing process of the moving picture, the controller outputting the decoding command and the drawing command at respective timings so that the decoding process and the drawing process are performed asynchronously with respect to each other; and a display control section that performs the drawing process for displaying the image data stored in the frame memory on the display device, the display control section being configured to receive the drawing command from the controller, to read the image data from the frame buffer designated by the drawing command among the frame buffers of the ring buffer, and to reflect the read image data on the image data stored in the frame memory, wherein the drawing process and the decoding process are performed in parallel but independently of each other, wherein the decoding section includes a drawing-completed frame buffer pointer that indicates a frame buffer storing the image data that has completed the drawing process, and the decoding section continues the decoding process on condition that a frame buffer available for storing a decoding result of the compression encoded data of the moving picture is present among the frame buffers up to the frame buffer indicated by the drawing-completed frame buffer pointer, wherein the controller outputs an update command for update control of the drawing-completed frame buffer pointer to the decoding section in accordance with progression of the drawing process, wherein the controller supplies a manual update command to the decoding section when the controller outputs a new drawing command that changes designation of the frame buffer which stores the image data to be subjected to the drawing process, and wherein the decoding section executes the update control of the drawing-completed frame buffer pointer once in synchronism with vertical scanning of the display device whenever the manual update command is received.