W99681CF Datasheet, PDF (21/78 Pages) Winbond – JPEG USB Dual Mode Camera Chip

W99681CF
VICLK
Y[7:0]
UV[7:0]
Y[7:0]
UV[7:0]
Y[7:0]
Y[7:0]
Y[7:0]
Y[7:0]
Y0
Y1
Y2
Y3
Y4
Y5
Y6
U0
V0
U2
V2
U4
V4
U6
16-bit UV Mode (CR26_10-8=00x)
Y0
Y1
Y2
Y3
Y4
Y5
Y6
V0
U0
V2
U2
V4
U4
V6
16-bit VU Mode (CR26_10-8=01x)
Y0
U0
Y1
V0
Y2
U2
Y3
8-bit YUYV Mode (CR26_10-8=100)
U0
Y0
V0
Y1
U2
Y2
V2
8-bit UYVY Mode (CR26_10-8=101)
Y0
V0
Y1
U0
Y2
V2
Y3
8-bit YVYU Mode (CR26_10-8=110)
V0
Y0
U0
Y1
V2
Y2
U2
8-bit VYUY Mode (CR26_10-8=111)
Figure 7.1 Input Video Data Formats
7.1.3 Cropping
A cropping rectangle (or window) is supported for cropping or clipping the incoming video data. Only
interested video data located inside the cropping rectangle is processed and sent to the host system.
The cropping rectangle can be moved within the input rectangle by programming the Cropping Window
Start X and Cropping Window Start Y registers. Cropping is performed based on the VS signal for
vertical cropping and HS signal for horizontal cropping. Both VS and HS are programmable polarity for
maximum flexibility.
7.1.4 Scaling
The cropped video can be down-scaled horizontally and/or vertically. The horizontal down-scaling and
vertical down-scaling are performed independently by using two DDAs (Digital Differential Accumulator)
with
Horizontal
Down - scaling
Factor
=

 Cropping
Captured Video Width
Window End X − Cropping Window
Start

X 
and
Vertical
Down
-
scaling
Factor
=


Cropping
Captured Video Height
Window End Y − Cropping Window
Start
Y
 _.
The W99681CF does not perform up-scaling during video pre-processing. To produce CIF format from
240-line video for the JPEG compression, a special vertical up-scaling can be performed by the JPEG
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Publication Release Date: March 2000
Revision A1