VT8601 Via, VT8601 Datasheet - Page 104

• Manufacturer Part Number: VT8601
• Description: Slot-1 / Socket-370 PCI North Bridge
• Manufacturer: Via

Video Display and Capture Engine Registers
The ProMedia integrates video display and capture engines,
which support YUV 4:2:2, YUV12 (planar) or YUV 4:1:1
data formats to accelerate software playback and video
capture functions. Video images can be captured through a
special video capture port or the PCI bus. Dual apertures on
the PCI bus enable graphics and video data to be transported
simultaneously without any software involvement. The video
image can be smoothed through a programmable multi-tap
filter to reduce the jig-jag effect after minification. The video
data can be minified to save bus bandwidth or memory space
and written into offscreen memory. The video display engine
fetches YUV 4:2:2 or planar video data from offscreen
memory and can be scaled up with linear interpolation in both
X and Y directions. The video data stream is converted into a
True Color RGB24 data stream and multiplexed with the
graphics data. Two live video windows can be supported.
The graphics data and video data can be handled smoothly in
different color depths with color key support. A hardware
anti-tear mechanism prevents the tearing effect due to frame
buffer update and eases the burden of software to flip the
page. Since the hardware synchronizes the capture or PCI
video address pointer with the playback VSYNC, the built-in
algorithm ensures the playback frame buffer is free from the
frame update. For the parameters defined here, refer to the
following figures.
Note that W1’ is defined for the anti-tearing function. W1 is
the first live video storage area and W2 is the second live
video storage area. W1 could be in either packed pixel or
planar format, while W2 can only be packed pixel mode. If
W1 is in packed pixel mode, then W1-U and W1-V are not
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Figure 8. Live Video Display Parameters
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used. If W1 is in planar mode, then W1-Y is the first live
video Y-component storage area, and W1-U (V) is the first
live video U (V) -component storage area. In the following
register definitions, a register with W1 (W2) indicates that
this parameter is applicable to the first (second) live video
window only.
Figure 7. Frame Buffer Parameters
VT8601 Apollo ProMedia
VGA Extended Registers