Apply a frei0r effect to the input video.

To enable compilation of this filter you need to install the frei0r header and configure FFmpeg with --enable-frei0r.

The filter supports the syntax:

filter_name[{:|=}param1:param2:...:paramN]

filter_name is the name of the frei0r effect to load. If the environment variable FREI0R_PATH is defined, the frei0r effect is searched in each one of the directories specified by the colon (or semicolon on Windows platforms) separated list in FREIOR_PATH, otherwise in the standard frei0r paths, which are in this order: HOME/.frei0r-1/lib/, /usr/local/lib/frei0r-1/, /usr/lib/frei0r-1/.

param1, param2, ... , paramN specify the parameters for the frei0r effect.

A frei0r effect parameter can be a boolean (whose values are specified with "y" and "n"), a double, a color (specified by the syntax R/G/B, R, G, and B being float numbers from 0.0 to 1.0) or by an av_parse_color() color description), a position (specified by the syntax X/Y, X and Y being float numbers) and a string.

The number and kind of parameters depend on the loaded effect. If an effect parameter is not specified the default value is set.

Some examples follow:

• Apply the distort0r effect, set the first two double parameters:

  frei0r=distort0r:0.5:0.01

• Apply the colordistance effect, take a color as first parameter:

  frei0r=colordistance:0.2/0.3/0.4
  frei0r=colordistance:violet
  frei0r=colordistance:0x112233

• Apply the perspective effect, specify the top left and top right image positions:

  frei0r=perspective:0.2/0.2:0.8/0.2

For more information see: http://frei0r.dyne.org