Add support for Bauer stereophonic-to-binaural (bs2b)

[Farnjang]

What do you want to be added?

Support for Bauer stereophonic-to-binaural DSP

Additional context

BS2B reduces the 'stereo fatigue' one can experience when listening to music with headphones for extended periods of time

[iiPythonx]

According to the ffmpeg bs2b docs, you can add the following to your Feishin MPV parameters:

--af-add=lavfi=[bs2b=profile=default]

Substituting default with your profile of choice, or manually setting fcut and feed to your liking.

[kgarner7]

Given that there is an FFmpeg option for mpv, and no plans to do something similar for web audio (although it is technically possible), I'm going to go ahead and close this issue.