As image displaying techniques are rapidly developed, more and more display interfaces such as television (TV) sets and computer screens have upgraded to support high definition (HD) display in addition to standard definition (SD) display. That is, there are multi-format display interfaces which are capable of supporting displaying of various data information sizes available currently. To display image frames of different data information sizes on the multi-format display interface becomes an important issue.
Taking TV display as an example, image frames of resolution formats 480i (dimension: 720×480), 576i (dimension: 720×576), 480p (dimension: 720×480), and 576p (dimension: 720×576) are classified as SD formats. Images frames of resolution formats 720p (dimension: 1280×720) and 1080i (dimension: 1920×1080) and 1080p (dimension: 1920×1080) are classified as HD formats, in which 1080p is referred to “full HD”. The character “i” indicates “interlace”, means that a frame is divided into two fields to be output at two time points. The character “p” indicates “progressive”, means that a frame is scanned line by line and output at a time. As known, the progressive display scheme needs a bandwidth which is almost double as compared to that required by the interface scheme. The dimension of an image frame of 200 million pixels is about the same as full HD.
For an image output device such as a digital camera, the dimension of the output image frame is of the order of millions of pixels, or even higher. In addition, the image frame which meets the standard of blu-ray disc (BD) or HDTV is at the grade of HD format. To display high-resolution images of various formats on the display interface (e.g. a TV set) with a selected resolution, flexible and adaptable adjustment of resolution to the image is required.