FFT-based FIR

FFT-based FIR

Status:

Maintained

Keyframes:

No

Source library:

avfilter

Source filter:

fftfilt

Available:

On Master only:

No

Known bugs:

No

Description

This effect/filter applies arbitrary expressions to samples in frequency domain. It is a Finite Impulse Response (FIR)[1] filter using Fast Fourier Transform (FFT)[2].

Parameters

Parameter	Value	Description
Gain in Y / U / V plane	Integer	Set the gain value for the Y (luma), U (1st chroma) or V (2nd chroma) plane. Allowed values are 0 to 250, default is 0.
Luminance Y / U / V plane	Float	Set the frequency domain weight value for the Y (luma), U (1st chroma) or V (2nd chroma) plane. Allowed values are 0.000 to 5.000, default is 1.000.
Evaluate	Selection	Set when the expressions are evaluated.

The following selection items are available:

Evaluate

init	Only evaluate expressions once during filter initialization (default)
frame	Evaluate expressions for each incoming frame

Warnung

If Evaluate is set to frame render times will be significantly longer as each frame is evaluated individually.

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[1]

For more information about FIR see this article: What is an FIR filter?

[2]

This is a good introduction to Fourier Transforms in image processing.