fftfilt
Apply arbitrary expressions to samples in frequency domain
- 'dc_Y'
-
Adjust the dc value (gain) of the luma plane of the image. The filter accepts an integer value in range
0
to1000
. The default value is set to0
. - 'dc_U'
-
Adjust the dc value (gain) of the 1st chroma plane of the image. The filter accepts an integer value in range
0
to1000
. The default value is set to0
. - 'dc_V'
-
Adjust the dc value (gain) of the 2nd chroma plane of the image. The filter accepts an integer value in range
0
to1000
. The default value is set to0
. - 'weight_Y'
-
Set the frequency domain weight expression for the luma plane.
- 'weight_U'
-
Set the frequency domain weight expression for the 1st chroma plane.
- 'weight_V'
-
Set the frequency domain weight expression for the 2nd chroma plane.
- 'eval'
-
Set when the expressions are evaluated.
It accepts the following values:
- 'init'
-
Only evaluate expressions once during the filter initialization.
- 'frame'
-
Evaluate expressions for each incoming frame.
Default value is 'init'.
The filter accepts the following variables:
- 'X'
- 'Y'
-
The coordinates of the current sample.
- 'W'
- 'H'
-
The width and height of the image.
- 'N'
-
The number of input frame, starting from 0.
Command line examples
- High-pass:
fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
- Low-pass:
fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
- Sharpen:
fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
- Blur:
fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'