Filter afreqshift
  Apply frequency shifting to input audio.
    slice threading supported
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
afreqshift AVOptions:
  shift             <double>     ..F.A....T set frequency shift (from -2.14748e+09 to INT_MAX) (default 0)

This filter has support for timeline through the 'enable' option.

