PIXCI® SV
Tech Tip: Video Display for PIXCI® SV4

The PIXCI® SV4 imaging board captures video, at video rate, directly into PC memory. One method of image display is by having software copy captured images to the S/VGA. The liveliness of the image display - whether the display is full video rate, or near video rate - depends upon:
  1. The captured image's dimensions and whether it is monochrome or color. Larger images and color images require more processing, and the display may be slower.
  2. Whether the image is enhanced or colorized via lookup tables. Enhancements require more processing, and the display may be slower.
  3. The S/VGA resolution, and the displayed image's relative size. Higher resolution S/VGA displays require more data, and the display may be slower.
  4. Whether the displayed image is the same (pixel) size as the captured image, and whether the display is in monochrome mode or color mode. Resizing images requires more processing, and the display may be slower.
  5. For color video, whether the PIXCI® SV4 is generating YCrCb, using 2 bytes per pixel, or RGB using 3 bytes per pixel. The YCrCb uses less PCI bandwidth for capture, but must be converted into RGB by the processor. The RGB uses more PCI bandwidth for capture, but no extra processing is required.
  6. The speed of the PC. Processor speed, memory caches, and PCI bus bandwidth all have an effect.
  7. The speed of the S/VGA card.

The tables at right show display performance using XCAP for Windows 95.

Under Windows 95, selected S/VGA cards can receive images directly from the PIXCI® SV4, providing full, live, video display for images of any size; request the Live Video & Overlays for Win 95 Tech Tip for additional information on this feature. Capturing into PC memory has the advantage of allowing simultaneous processor access to the pixel data; sending video directly to the S/VGA card does not allow access to pixel data.

Image Display Rate - 30 fps Video Source with ATI Rage Pro (Chipset) AGP S/VGA with 233 MHz Pentium II
S/VGA Mode PIXCI® SV4 Mode Display Size Display Rate
640x480x24 Mono full VGA 30 fps
640x480x24 YCrCb 1/4 VGA 30 fps
640x480x24 YCrCb full VGA 16 fps
640x480x24 RGB full VGA 30 fps
800x600x24 Mono full VGA 26 fps
800x600x24 Mono 1/4 VGA 30 fps
800x600x24 YcrCb 1/6 VGA 30 fps
800x600x24 YcrCb 1/4 VGA 26 fps
800x600x24 YcrCb full VGA 11 fps
800x600x24 RGB full VGA 30 fps

Image Display Rate - 30 fps Video Source w. Diamond Viper 330 Riva 128 Chipset AGP S/VGA with 233 MHz Pentium II
S/VGA Mode PIXCI® SV4 Mode Display Size Display Rate
640x480x32 Mono full VGA 30 fps
640x480x32 YCrCb 1/4 VGA 30 fps
640x480x32 YCrCb full VGA 13 fps
640x480x32 RGB full VGA 30 fps
800x600x32 YcrCb 1/4 VGA 25 fps
800x600x32 YcrCb full VGA 10 fps

Image Display Rate - 30 fps Video Source with Hercules Dynamite 128 PCI S/VGA with 200 MHz Pentium Pro
S/VGA Mode PIXCI® SV4 Mode Display Size Display Rate
640x480x24 Mono 1/4 VGA 30 fps
640x480x24 Mono full VGA 23 fps
640x480x24 YCrCb 1/6 VGA 30 fps
640x480x24 YCrCb 1/4 VGA 21 fps
640x480x24 YCrCb full VGA 10 fps
640x480x24 RGB 1/4 VGA 30 fps
640x480x24 RGB full VGA 23 fps

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Modified:
27-Feb-2017