Filter derain
  Apply derain filter to the input.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
derain AVOptions:
  filter_type       <int>        ..FV..... filter type(derain/dehaze) (from 0 to 1) (default derain)
     derain          0            ..FV..... derain filter flag
     dehaze          1            ..FV..... dehaze filter flag
  dnn_backend       <int>        ..FV..... DNN backend (from 0 to 1) (default native)
     native          0            ..FV..... native backend flag
  model             <string>     ..FV..... path to model file

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

