FFmpeg 2.5.11
Since* 2.0
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Make or reverse a natural vignetting effect.

The filter accepts the following options:

angle, a

Set lens angle expression as a number of radians.

The value is clipped in the [0,PI/2] range.

Default value: "PI/5"

x0, y0

Set center coordinates expressions. Respectively "w/2" and "h/2" by default.

mode

Set forward/backward mode.

Available modes are:

forward

The larger the distance from the central point, the darker the image becomes.

backward

The larger the distance from the central point, the brighter the image becomes. This can be used to reverse a vignette effect, though there is no automatic detection to extract the lens angle and other settings (yet). It can also be used to create a burning effect.

Default value is forward.

eval

Set evaluation mode for the expressions (angle, x0, y0).

It accepts the following values:

init

Evaluate expressions only once during the filter initialization.

frame

Evaluate expressions for each incoming frame. This is way slower than the init mode since it requires all the scalers to be re-computed, but it allows advanced dynamic expressions.

Default value is init.

dither

Set dithering to reduce the circular banding effects. Default is 1 (enabled).

aspect

Set vignette aspect. This setting allows one to adjust the shape of the vignette. Setting this value to the SAR of the input will make a rectangular vignetting following the dimensions of the video.

Default is 1/1.

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Expressions

The alpha, x0 and y0 expressions can contain the following parameters.

w, h

input width and height

n

the number of input frame, starting from 0

pts

the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in TB units, NAN if undefined

r

frame rate of the input video, NAN if the input frame rate is unknown

t

the PTS (Presentation TimeStamp) of the filtered video frame, expressed in seconds, NAN if undefined

tb

time base of the input video

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Examples

  • Apply simple strong vignetting effect:

    vignette=PI/4
  • Make a flickering vignetting:

    vignette='PI/4+random(1)*PI/50':eval=frame