Filter aeval
  Filter audio signal according to a specified expression.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
aeval AVOptions:
  exprs             <string>     ..F.A.... set the '|'-separated list of channels expressions
  channel_layout    <string>     ..F.A.... set channel layout
  c                 <string>     ..F.A.... set channel layout


