Fill borders of the input video, without changing video stream dimensions. Sometimes video can have garbage at the four edges and you may not want to crop video input to keep size multiple of some number.

This filter accepts the following options:

left

Number of pixels to fill from left border.

right

Number of pixels to fill from right border.

top

Number of pixels to fill from top border.

bottom

Number of pixels to fill from bottom border.

mode

Set fill mode.

It accepts the following values:

smear

fill pixels using outermost pixels

mirror

fill pixels using mirroring (half sample symmetric)

fixed

fill pixels with constant value

reflect

fill pixels using reflecting (whole sample symmetric)

wrap

fill pixels using wrapping

fade

fade pixels to constant value

margins

fill pixels at top and bottom with weighted averages pixels near borders

Default is smear.

color

Set color for pixels in fixed or fade mode. Default is black.