| 摘要 |
PURPOSE: A method and apparatus is provided for downsizing a digital video image, such as an image corresponding to the MPEG-2 standard. CONSTITUTION: A method and apparatus for downsizing a digital video image, such as an image corresponding to the MPEG-2 standard. A system is particularly suitable for providing a reduced image for a picture-in-picture mode on a television. Digital video pixel data that is received from a channel is decompressed to provide pixel data of an original image (e.g., A1, A2, A3, A4). Horizontally adjacent pixel pairs of the original image are averaged to provide horizontally downsized pixel data (e.g., (A1+A2)/2, (A3+A4)/2), which is stored in a first bank of a multi-bank memory. Data from every other pixel of the original image (e.g., A2, A4) is stored in a second bank of the dual-bank memory. To obtain a downsized image, vertically adjacent lines of the horizontally downsized pixel data are retrieved from the first bank, and averaged to provide vertically and horizontally downsized pixel data for display. Alternatively, to recover pixel data corresponding to the original image for decompressing predictive-coded images, portions of the horizontally downsized pixel data may be retrieved from the first bank with corresponding portions of the data from the second bank (e.g., A1=2(A1+A2)/2-A2). |
