PNX1311EH NXP Semiconductors, PNX1311EH Datasheet - Page 233

• Manufacturer Part Number: PNX1311EH
• Manufacturer: NXP Semiconductors

Specifications of PNX1311EH

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Philips Semiconductors
Table 14-13. Horizontal filter parameter table
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. The Integer value is a 16-bit in-
teger, and the Fraction value is a positive binary fraction
between 0 and 0.99999+. For up scaling (output image
bigger), the increment value is the inverse of the scaling
value. If you are upscaling by a factor of 2.5, the incre-
ment value will be the inverse of 2.50 = 0.40. The Integer
increment value will be 0 and the Fraction increment val-
ue 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 increment value will be 0.500.
To perform scaling, the Integer and Fractional increment
values must be generated and placed in the parameter
table. The simplest way to generate these values in com-
mon computer languages such as C is as follows:
1. Generate the Increment Value as a floating point
2. Multiply the Increment Value by 65536
3. Convert the result to a Long Integer (32 bits). The up-
4. Store the 32-bit Long integer in the parameter table as
The Start Fraction defines the starting value in the scal-
ing counter for each line. It is a 16-bit, two’s complement
fractional value between -0.500 and +0.49999. The Start
Fraction allows the input data to be offset by up to half a
pixel, referred to the input pixel grid. It is ‘0’ for Y and for
UV co-sited data, and set to ‘-0.25’ (C000h) for inter-
spersed to co-sited conversion of U and V data. The ‘-
0.25’ value effectively shifts the U and V data toward the
start of the line by 1/4 pixel, the amount required for con-
version.
Input image start address
Y counter
Start fraction
Fraction increment
Input image height
Output image start address
Control
Output image height
number = Input Width / Output Width
per 16 bits of the Long integer will be the Integer in-
crement value, and the lower 16 bits will be the Frac-
tional value.
the combined Integer and Fractional increment val-
ues.
Upper 2 bytes
Parameter Word
Input image
Line offset
Integer increment
Input image Width
Output Image
Line offset
Output image width
Lower 2 bytes
Start address of X0Y0 (byte address)
Starting value: may be 0.5, etc. for interspersed convert;
Line offset from X0Y0 to X0Y1
Start address of X0Y0 (byte address)
Control bits; Line offset from X0Y0 to X0Y1
Height and width in output lines and pixels
Increment value for Y = 1/scale factor
Height and width in input lines and pixels
14.6.9.3
The Control word provides bit fields which affect the hor-
izontal filtering operation. The format of the Control word
is as follows.
Bit
15
9
The Bypass bit causes the data to bypass the 5-tap filter.
The scaling operation selects the center pixel, and this
pixel is passed to the filter output. No filtering or interpo-
lation is provided. If the scaling factor is ‘1.0’, the result is
an image block move where the image is moved from
one part of SDRAM to another without modification. If the
scaling factor is other than ‘1.0’, the effective algorithm is
pixel picking, where the input pixel nearest the output
pixel location is used as the output pixel.
The GETB bit is an optional bit for large (> 4) down scal-
ing. When GETB is ‘0’ (normal operation), the 5-tap filter
receives the pixel nearest the output pixel as its center
pixel plus the two adjacent input pixels on either side of
this pixel to form the five filter inputs. When GETB is set,
the filter receives the pixel nearest the output pixel as its
center pixel plus the two pixels nearest the adjacent out-
put pixels on either side of this pixel to form the five filter
inputs. The effective algorithm is pixel picking plus 5-tap
filtering of the result. GETB also forces the scaling LSB
value to ‘0’, since output pixels are being filtered and no
PRELIMINARY SPECIFICATION
Name
Bypass
GETB
Control word format
Bypass filter. Picks nearest input pixel
and passes it to output unfiltered.
When Bypass is set & scale factor is
1.0, this results in an image block
move
Large down-scaling bit. Picks nearest
input pixels and passes them to filter.
Equivalent to bypass + 5-tap filter of
output pixels. LSB value = 0 for filter-
ing.
Description
Function
Image Coprocessor
14-23