Filter acrossfade
  Cross fade two input audio streams.
    Inputs:
       #0: crossfade0 (audio)
       #1: crossfade1 (audio)
    Outputs:
       #0: default (audio)
acrossfade AVOptions:
  nb_samples        <int>        ..F.A.... set number of samples for cross fade duration (from 1 to 2.14748e+008) (default 44100)
  ns                <int>        ..F.A.... set number of samples for cross fade duration (from 1 to 2.14748e+008) (default 44100)
  duration          <duration>   ..F.A.... set cross fade duration (default 0)
  d                 <duration>   ..F.A.... set cross fade duration (default 0)
  overlap           <boolean>    ..F.A.... overlap 1st stream end with 2nd stream start (default true)
  o                 <boolean>    ..F.A.... overlap 1st stream end with 2nd stream start (default true)
  curve1            <int>        ..F.A.... set fade curve type for 1st stream (from 0 to 17) (default tri)
     tri             0            ..F.A.... linear slope
     qsin            1            ..F.A.... quarter of sine wave
     esin            2            ..F.A.... exponential sine wave
     hsin            3            ..F.A.... half of sine wave
     log             4            ..F.A.... logarithmic
     ipar            5            ..F.A.... inverted parabola
     qua             6            ..F.A.... quadratic
     cub             7            ..F.A.... cubic
     squ             8            ..F.A.... square root
     cbr             9            ..F.A.... cubic root
     par             10           ..F.A.... parabola
     exp             11           ..F.A.... exponential
     iqsin           12           ..F.A.... inverted quarter of sine wave
     ihsin           13           ..F.A.... inverted half of sine wave
     dese            14           ..F.A.... double-exponential seat
     desi            15           ..F.A.... double-exponential sigmoid
     losi            16           ..F.A.... logistic sigmoid
     nofade          17           ..F.A.... no fade; keep audio as-is
  c1                <int>        ..F.A.... set fade curve type for 1st stream (from 0 to 17) (default tri)
     tri             0            ..F.A.... linear slope
     qsin            1            ..F.A.... quarter of sine wave
     esin            2            ..F.A.... exponential sine wave
     hsin            3            ..F.A.... half of sine wave
     log             4            ..F.A.... logarithmic
     ipar            5            ..F.A.... inverted parabola
     qua             6            ..F.A.... quadratic
     cub             7            ..F.A.... cubic
     squ             8            ..F.A.... square root
     cbr             9            ..F.A.... cubic root
     par             10           ..F.A.... parabola
     exp             11           ..F.A.... exponential
     iqsin           12           ..F.A.... inverted quarter of sine wave
     ihsin           13           ..F.A.... inverted half of sine wave
     dese            14           ..F.A.... double-exponential seat
     desi            15           ..F.A.... double-exponential sigmoid
     losi            16           ..F.A.... logistic sigmoid
     nofade          17           ..F.A.... no fade; keep audio as-is
  curve2            <int>        ..F.A.... set fade curve type for 2nd stream (from 0 to 17) (default tri)
     tri             0            ..F.A.... linear slope
     qsin            1            ..F.A.... quarter of sine wave
     esin            2            ..F.A.... exponential sine wave
     hsin            3            ..F.A.... half of sine wave
     log             4            ..F.A.... logarithmic
     ipar            5            ..F.A.... inverted parabola
     qua             6            ..F.A.... quadratic
     cub             7            ..F.A.... cubic
     squ             8            ..F.A.... square root
     cbr             9            ..F.A.... cubic root
     par             10           ..F.A.... parabola
     exp             11           ..F.A.... exponential
     iqsin           12           ..F.A.... inverted quarter of sine wave
     ihsin           13           ..F.A.... inverted half of sine wave
     dese            14           ..F.A.... double-exponential seat
     desi            15           ..F.A.... double-exponential sigmoid
     losi            16           ..F.A.... logistic sigmoid
     nofade          17           ..F.A.... no fade; keep audio as-is
  c2                <int>        ..F.A.... set fade curve type for 2nd stream (from 0 to 17) (default tri)
     tri             0            ..F.A.... linear slope
     qsin            1            ..F.A.... quarter of sine wave
     esin            2            ..F.A.... exponential sine wave
     hsin            3            ..F.A.... half of sine wave
     log             4            ..F.A.... logarithmic
     ipar            5            ..F.A.... inverted parabola
     qua             6            ..F.A.... quadratic
     cub             7            ..F.A.... cubic
     squ             8            ..F.A.... square root
     cbr             9            ..F.A.... cubic root
     par             10           ..F.A.... parabola
     exp             11           ..F.A.... exponential
     iqsin           12           ..F.A.... inverted quarter of sine wave
     ihsin           13           ..F.A.... inverted half of sine wave
     dese            14           ..F.A.... double-exponential seat
     desi            15           ..F.A.... double-exponential sigmoid
     losi            16           ..F.A.... logistic sigmoid
     nofade          17           ..F.A.... no fade; keep audio as-is


