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.
- WS, HS
-
The size of FFT array for horizontal and vertical processing.
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)))'