Filter interlace
  Convert progressive video into interlaced.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
interlace AVOptions:
  scan              <int>        ..FV.... scanning mode (from 0 to 1) (default tff)
     tff                          ..FV.... top field first
     bff                          ..FV.... bottom field first
  lowpass           <int>        ..FV.... set vertical low-pass filter (from 0 to 2) (default linear)
     off                          ..FV.... disable vertical low-pass filter
     linear                       ..FV.... linear vertical low-pass filter
     complex                      ..FV.... complex vertical low-pass filter


