User guide

Table Of Contents
21–12 Chapter 21: Scaler MegaCore Function
Parameter Settings
Video and Image Processing Suite January 2013 Altera Corporation
User Guide
Number of horizontal
phases
2, 4, 8, 16, 32,
64, 128, 256
Specify the number of horizontal phases.
Vertical Coefficient
Precision: Signed
On or Off
Turn on if you want the fixed-point type that stores the vertical coefficients
to have a sign bit.
Vertical Coefficient
Precision: Integer bits:
0–15, Default = 1
Specifies the number of integer bits for the fixed-point type used to store
the vertical coefficients.
Vertical Coefficient
Precision: Fraction bits:
3–15, Default = 7
Specifies the number of fractional bits for the fixed point type used to
store the vertical coefficients.
Number of bits to preserve
between vertical and
horizontal filtering
(1)
3–32, Default = 9
Specifies the number of bits to preserve between vertical and horizontal
filtering.
Horizontal Coefficient
Precision: Signed
On or Off
Turn on if you want the fixed-point type that stores the horizontal
coefficients to have a sign bit.
Horizontal Coefficient
Precision: Integer bits:
0–15, Default = 1
Specifies the number of integer bits for the fixed-point type used to store
the horizontal coefficients.
Horizontal Coefficient
Precision: Fraction bits:
0–15, Default = 7
Specifies the number of fractional bits for the fixed point type used to
store the horizontal coefficients.
Note to Table 21–5:
(1) These parameters determine the number and size of the DSP blocks. For example, with four vertical and four horizontal taps and nine bits
preserved between vertical and horizontal filtering, the scaler uses a total of eight 9×9 DSP blocks.
Table 21–5. Scaler Parameter Settings Tab, Algorithm and Precision Page (Part 2 of 2)
Parameter Value Description
Table 21–6. Scaler Parameter Settings Tab, Coefficients Page (Part 1 of 2)
Parameter Value Description
Load coefficient data at run
time
On or Off Turn on to load the coefficient data at run time.
Share horizontal / vertical
coefficients
On or Off
Turn on to map horizontal and vertical coefficients to the same
memory. When on and Load coefficient data at run time is also
on, writes to the vertical coefficients are ignored. (The choice of
read bank remains independent for horizontal and vertical
coefficients.)
Vertical Coefficient Data:
Memory banks
1–6, Default = 2
Choose the number of coefficient banks to enable double-
buffering, fast coefficient swapping or direct writes.
Vertical Coefficient Data:
Filter function
Lanczos 1–12, or Custom,
Default = Lanczos 2
You can choose from 12 pre-defined Lanczos functions or use
the coefficients saved in a custom coefficients file.
Vertical Coefficient Data:
Custom coefficient file
User specified
When a custom function is selected, you can browse for a
comma-separated value file containing custom coefficients. Key
in the path for the file that contains these custom coefficients.
Use the Preview coefficients button to view the current
coefficients in a preview window.
Vertical Coefficient Data:
Symmetric
On or Off
Turn on to save coefficient memory by using symmetric
coefficients. When on and Load coefficient data at run time is
also on, coefficient writes beyond phases 2 and 1 are ignored.
Horizontal Coefficient Data:
Memory banks
1–6, Default = 2
Choose the number of coefficient banks to enable double-
buffering, fast coefficient swapping or direct writes.
Horizontal Coefficient Data:
Filter function
Lanczos 1–12, or Custom,
Default = Lanczos 2
You can choose from 12 pre-defined Lanczos functions or use
the coefficients saved in a custom coefficients file.