Blur (clip, float amount)
Blur (clip, float amountH, float amountV, bool MMX)
Sharpen (clip, float amount)
Sharpen (clip, float amountH, float amountV, bool MMX)
This is a simple 3x3-kernel blurring filter. The largest allowable argument for
Blur is about 1.58, which corresponds to a (1/3,1/3,1/3) kernel.
A value of 1.0 gets you a (1/4,1/2,1/4) kernel. If you want a large-radius
Gaussian blur, I recommend chaining several copies of Blur(1.0)
together. (Anybody remember Pascal's triangle?)
Negative arguments to Blur actually sharpen the image, and in fact
Sharpen(n) is just an alias for Blur(-n). The smallest
allowable argument to Blur is -1.0 and the largest to
Sharpen is 1.0.
You can use 2 arguments to set independent Vertical and Horizontal amounts.
Like this, you can use Blur(0,1) to filter only Vertically,
for example to blend interlaced lines together. By default
amountV=amountH.
A Known issue, with the MMX routines is the lack of full 8 bit precision in the calculations. This can lead to banding in the resultant image. Set the MMX=False option to use the slower but more accurate C++ routines if this is a concern.
$Date: 2006/12/03 11:37:04 $