Filter asetrate
  Change the sample rate without altering the data.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
asetrate AVOptions:
  sample_rate       <int>        ..F.A.... set the sample rate (from 1 to INT_MAX) (default 44100)
  r                 <int>        ..F.A.... set the sample rate (from 1 to INT_MAX) (default 44100)


