Compute and apply a lookup table from two video inputs.
This filter accepts the following parameters:
- c0
-
set first pixel component expression
- c1
-
set second pixel component expression
- c2
-
set third pixel component expression
- c3
-
set fourth pixel component expression, corresponds to the alpha component
Each of them specifies the expression to use for computing the lookup table for the corresponding pixel component values.
The exact component associated to each of the c* options depends on the format in inputs.
The expressions can contain the following constants:
- w, h
-
The input width and height.
- x
-
The first input value for the pixel component.
- y
-
The second input value for the pixel component.
- bdx
-
The first input video bit depth.
- bdy
-
The second input video bit depth.
All expressions default to "x".
Examples
-
Highlight differences between two RGB video streams:
lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1)'
-
Highlight differences between two YUV video streams:
lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1)'