The LogiCORE IP Video Scaler allows you to initialize the scaling coefficients using the COE file or to program them at a later time.
The next sections describe where to find information on how to create coefficients and how to format them for a COE file.
To generate coefficients, use one of the following methods:
COE File Format
Note: This applies to the LogiCORE IP Video Scaler v3.0 and newer.
Prior to LogiCORE IP Video Scaler v3.0, the COE input was in a different format.
It is highly recommended that all users update to the latest version of the LogiCORE IP Video Scaler.
The Video Scaler Product Guide (PG009) documents the COE file format in the "Coefficients" section.
The COE file follows the same format as found in the pcore interface to make it easier to input your coefficients at configuration or run-time depending on your application.
Xilinx LogiCORE IP Video Scaler C Model (Same coefficients as the pcore Driver):
Xilinx released a C Model with the release of the LogiCORE IP Video Scaler v4.0.
This C Model also provides the capability to generate coefficients in a ".coe" format that can be used with the LogiCORE IP Video Scaler.
For more information on how to generate a ".coe" file, see the latest version of the Video Scaler Product Guide (PG009).
Xilinx pcore Coefficients (Same coefficients as the C Model):
If you generate the LogiCORE IP Video Scaler with the pcore interface, it delivers a predefined set of scaling coefficients.
These can be found in the following file:v_scaler_v3_0_u0\drivers\scaler_v3_00_a\src\xscaler_coefs.c
The size of the xscaler_coefs.c file is quite large, and most applications probably do not need all of the coefficients.
The size of the xscaler_coefs.c file can be reduced by manually removing the unnecessary coefficients, and by modifying the provided driver files for the video scaler.
In a future release, there will be an automated method of generating a coefficient file with a reduced set of coefficients.
Third Party Tools:
There are many tools and methods for creating scaler coefficients.
Xilinx uses the Mathworks MATLAB tool to generate the coefficients provided in the xscaler_coefs.c file, which are based on the Lanczos algorithm.
You can use Google or Bing to search for other tools or algorithms.
You can also look at IEEE partners on Video Scaler design.
The following list might be useful as a starting point to find the algorithm that best fits your application:
Bilinear -The Video Scaler emulates a Bilinear implementation when you select two taps.
Bicubic - The Video Scaler emulates a Bicubic implementation when you select four taps.
For a detailed list of LogiCORE IP Video Scaler Release Notes and Known Issues, see (Xilinx Answer 31958).