Swap two rectangular objects in video.

This filter accepts the following options:

w

Set object width.

h

Set object height.

x1

Set 1st rect x coordinate.

y1

Set 1st rect y coordinate.

x2

Set 2nd rect x coordinate.

y2

Set 2nd rect y coordinate.

All expressions are evaluated once for each frame.

The all options are expressions containing the following constants:

w, h

The input width and height.

a

same as w / h

sar

input sample aspect ratio

dar

input display aspect ratio, it is the same as (w / h) * sar

n

The number of the input frame, starting from 0.

t

The timestamp expressed in seconds. It’s NAN if the input timestamp is unknown.

pos

the position in the file of the input frame, NAN if unknown