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             0            ..FV..... top field first
     bff             1            ..FV..... bottom field first
  lowpass           <flags>      ..FV..... set vertical low-pass filter (default linear)
     off                          ..FV..... disable vertical low-pass filter
     linear                       ..FV..... linear vertical low-pass filter
     complex                      ..FV..... complex vertical low-pass filter


