Filter geq
  Apply generic equation to each pixel.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
geq AVOptions:
  lum_expr          <string>     ..FV.... set luminance expression
  lum               <string>     ..FV.... set luminance expression
  cb_expr           <string>     ..FV.... set chroma blue expression
  cb                <string>     ..FV.... set chroma blue expression
  cr_expr           <string>     ..FV.... set chroma red expression
  cr                <string>     ..FV.... set chroma red expression
  alpha_expr        <string>     ..FV.... set alpha expression
  a                 <string>     ..FV.... set alpha expression
  red_expr          <string>     ..FV.... set red expression
  r                 <string>     ..FV.... set red expression
  green_expr        <string>     ..FV.... set green expression
  g                 <string>     ..FV.... set green expression
  blue_expr         <string>     ..FV.... set blue expression
  b                 <string>     ..FV.... set blue expression

This filter has support for timeline through the 'enable' option.

