Filter sinc
  Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients.
    Inputs:
        none (source filter)
    Outputs:
       #0: default (audio)
sinc AVOptions:
  sample_rate       <int>        ..F.A.... set sample rate (from 1 to INT_MAX) (default 44100)
  r                 <int>        ..F.A.... set sample rate (from 1 to INT_MAX) (default 44100)
  nb_samples        <int>        ..F.A.... set the number of samples per requested frame (from 1 to INT_MAX) (default 1024)
  n                 <int>        ..F.A.... set the number of samples per requested frame (from 1 to INT_MAX) (default 1024)
  hp                <float>      ..F.A.... set high-pass filter frequency (from 0 to INT_MAX) (default 0)
  lp                <float>      ..F.A.... set low-pass filter frequency (from 0 to INT_MAX) (default 0)
  phase             <float>      ..F.A.... set filter phase response (from 0 to 100) (default 50)
  beta              <float>      ..F.A.... set kaiser window beta (from -1 to 256) (default -1)
  att               <float>      ..F.A.... set stop-band attenuation (from 40 to 180) (default 120)
  round             <boolean>    ..F.A.... enable rounding (default false)
  hptaps            <int>        ..F.A.... set number of taps for high-pass filter (from 0 to 32768) (default 0)
  lptaps            <int>        ..F.A.... set number of taps for low-pass filter (from 0 to 32768) (default 0)


