
FUJISTU LIMITED PRELIMINARY AND CONFIDENTIAL
MB86295S <Coral-LP>
71
Specification Manual Rev1.1
6.4 Scaling
6.4.1 Downscaling Function
When the CM bits of the video capture mode register (VCM) are 11, Coral reduces the video screen
size. The reduction can be set independently in the vertical and horizontal scales. The reduction is
set per line in the vertical direction and in 2-pixel units in the horizontal direction. The scale setting
value is defined by an input/output value. It is a 16-bit fixed fraction where the integer is represented
by 5 bits and the fraction is represented by 11 bits. Valid setting values are from 0800H to FFFF H. Set
the vertical direction at bit 31 to bit 16 of the capture scale register (CSC) and the horizontal direction
at bits 15 to bit 00.
The initial value for this register is 08000800H (once).
An example of the
expressions for setting a reductio n in the vertical and horizontal directions is shown below.
Reduction in vertical direction
576
→ 490 lines
576/490 = 1.176
1.176
×2048=2408
→ 0968H
Reduction in horizontal direction
720
→ 648 pixels
720/648 = 1.111
1.111
×2048=2275
→ 08E3H
Therefore, 096808E3H is set in CSC.
The capture horizontal pixel register (CHP) and capture vertical pixel register (CVP) are used to limit
the number of pixels processed during scaling. They are not used to set scaling values. Clamp
processing is performed on the video streaming data outside the values set in CHP and CVP. Usually,
the defaults for these registers are used.
6.4.2 Upscaling Function
Coral is able to enlarge the size of a video capture picture by the factor of 2 in both the horizontal and
vertical directions. This feature can be used to realize full-screen modes of video input streams which
have a resolution less than actual display size. In order to use magnify (up-scaling) mode, the
horizontal and vertical factor must be less than one. Do not specify different scaling ways
(reduction/enlargement) for horizontal and vertical factors ! Also initialize the following registers as
follows :
Set the magnify flag in the L1-layer mode register of the display controller.
Set the picture source size (before magnification) into CMSHP and CMSVL.
Set the final picture size (after magnification) into CMDHP and CMDVL.
An example of the expressions for setting an enlargement in the vertical and horizontal directions is
shown below :
If the input picture size is 480x360 and the display picture size is 640x480, then the parameters for
each register are as follows.
HSCALE=(480/640)*2048=0x0600
VSCALE=(360/480)*2048=0x0600
CMSHP=0x00f0
CMSVL=0x0168
CMDHP=0x0140
CMDVL=0x01e0
L1WW=0x0280
L1WH=0x01df