| 摘要 |
A video and graphics system provides square graphics pixels to blend images having 640x480 pixels, such as graphics images provided by some set top boxes and intended to be displayed at a 12.27 MHz display sample rate, with images having 704x480 pixels, such as ITU-R 601 compliant images such as NTSC SDTV images, having oblong pixels and displayed at a 13.5 MHz display sample rate. A sample rate converter including a multi-phase-multi-tap filter is used to generate square pixels. The multi-phase-multi-tap filter provides a good balance of sharpness, smoothness, anti-aliasing and reduced ringing. The multi-phase-multi-tap filter can also be used to convert images having 320x480 pixels to images having 704x480 pixels. The multi-tap filter can be used for scan rate conversion of graphics or video images for HDTV or SDTV applications. |
