PNX1300/01/02/11 Data Book
Philips Semiconductors
14-26
PRELIMINARY SPECIFICATION
14.6.11.2 Parameter table
The parameter table, shown in
Table 14-14
, supplies the
input and output starting addresses and offsets for Y, U,
V, OL, B and Z, the image height in lines and width in pix-
els, and the scale factors for each component.
The input and output addresses are the byte addresses
of their respective tables. They do not need to be word or
block aligned. Note the following restriction: in packed
RGB24 to PCI operation the output address offset from
the start of video memory must be a multiple of 6 bytes,
i.e. on an even pixel boundary.
The input and output line offsets define the difference in
bytes from the address of the first pixel in the first line to
the address of the first pixel in the second line for their re-
spective blocks. The line offset must be constant for all
lines in each table. The line offset allows some space be-
tween the end of one line and the start of the next line. It
also allows the ICP to scale and filter a subset of an ex-
isting image, such as magnifying a portion of an image.
There are no restrictions on line offset values other than
they must be 16-bit, two
’
s complement integer values.
(Note that this allows negative offsets. You can use this
to flip an image vertically.)
The input and output image height and width values are
the height in lines and width in pixels per line for their re-
spective images. The height and width are 16-bit positive
binary numbers between 0 and 64K-1.
The Integer increment and Fraction increment values are
the scaling parameters. There is a separate scaling pa-
rameter for each of the Y, U and V input components.
The Integer value is a 16-bit integer, and the Fraction val-
ue is a positive binary fraction between 0 and 0.99999+.
For up scaling (output image bigger), the increment val-
ue is the inverse of the scaling value. If upscaling by a
factor of 2.5, the increment value will be the inverse of
2.50 = 0.40. The Integer increment value will be
‘
0
’
and
the Fraction increment value will be
‘
0.40
’
. For down
scaling, the increment value is equal to the scaling value.
If you are down scaling by 2.5 (output image smaller), the
Integer increment value will be
‘
2
’
, and the Fraction incre-
ment value will be
‘
0.500
’
.
To perform scaling, the Integer and Fractional increment
values must be generated and placed in the parameter
Table 14-14. Horizontal filter to RGB output parameter table
Parameter Word
Description
Upper 2 bytes
Lower 2 bytes
Input image Y start address
Y Counter
Start fraction
Y fraction increment
Y input image height
Input image U start address
U counter
Start fraction
U fraction increment
U input image height
Input image V start address
V Counter
Start fraction
V fraction increment
V Input image height
Output image start address
Control
Y Start address of X0Y0 (byte address)
Starting value: may be 0.5, etc. for interspersed convert;
Y Line offset from X0Y0 to X0Y1
Increment value for U = 1/scale factor
Y Height and width in pixels
U Start address of X0Y0 (byte address)
Starting value: may be 0.5, etc. for interspersed convert;
U Line offset from X0Y0 to X0Y1
Increment value for Y = 1/scale factor
U Height and width in pixels
V Start address of X0Y0 (byte address)
Starting value: may be 0.5, etc. for interspersed convert;
V Line offset from X0Y0 to X0Y1
Increment value for V = 1/scale factor
V Height and width in pixels
Start address of X0Y0 (byte address)
Input & output formats & control bits;
Line offset from X0Y0 to X0Y1
Height and width in output pixels
Start address of X0Y0 (byte address)
Line offset from X0Y0 to X0Y1
Input image
Y line offset
Y integer increment
Y input image width
Input image
U line offset
U integer increment
U input image Width
Input image
V line offset
V integer increment
V input image width
Output image
Line offset
Output image width
Output image height
Bit Map image start address
0
Bit map image
Line offset
RGB overlay start address
Alpha 1 & Alpha 0
Start address of X0Y0 (byte address)
Alpha 1 & Alpha 0 blend code for RGB15+
α
, etc.;
Line offset from X0Y0 to X0Y1
Start and end pixels along line
Start and end lines in frame
Overlay
Line offset
Overlay start pixel
Overlay start line
Overlay end pixel
Overlay end Line