Filter afftfilt
  Apply arbitrary expressions to samples in frequency domain.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
afftfilt AVOptions:
  real              <string>     ..F.A.... set channels real expressions (default "1")
  imag              <string>     ..F.A.... set channels imaginary expressions
  win_size          <int>        ..F.A.... set window size (from 4 to 17) (default w4096)
     w16                          ..F.A....
     w32                          ..F.A....
     w64                          ..F.A....
     w128                         ..F.A....
     w256                         ..F.A....
     w512                         ..F.A....
     w1024                        ..F.A....
     w2048                        ..F.A....
     w4096                        ..F.A....
     w8192                        ..F.A....
     w16384                       ..F.A....
     w32768                       ..F.A....
     w65536                       ..F.A....
     w131072                      ..F.A....
  win_func          <int>        ..F.A.... set window function (from 0 to 18) (default hann)
     rect                         ..F.A.... Rectangular
     bartlett                     ..F.A.... Bartlett
     hann                         ..F.A.... Hann
     hanning                      ..F.A.... Hanning
     hamming                      ..F.A.... Hamming
     sine                         ..F.A.... Sine
  overlap           <float>      ..F.A.... set window overlap (from 0 to 1) (default 0.75)


