Clean up MIDI stuff and document it

[endolith]

No description provided.

[endolith]

Current scheme of rotating through channels still has audible pitch shifts in it.

Alternatively, I could assign a certain amount of pitch shift to each channel and adjust it by a smaller amount, but then if you play multiple tones near that pitch shift it could still be audible.

Other possibilities:

• OpenSoundControl - Just a generic communication protocol, doesn't have any standard way of sending notes, de facto or otherwise
• MIDI Tuning Standard (MTS) - lets you define specific scales, but not send arbitrary frequencies?
• HD-MIDI - is an old name for MIDI 2.0? I think?
• MIDI 2.0 - has a "Note On With Attribute # 3 Pitch 7.9" that allows you to send individual notes with precise frequency? Yay that's what I want! Except it's not actually supported by any synthesizers yet. Boo.
• MIDI Polyphonic Expression (MPE) - lets you set pitch bends per-note? That seems good enough, too, but maybe also not supported by anything. 😕

Could MTS be combined with channel rotation to get an improved system?

[endolith]

Actually, maybe MPE is most commonly-supported?

• https://support.roli.com/support/solutions/articles/36000037202-compatible-synths-daws-and-instruments
• https://community.polyexpression.com/t/hardware-synths-supporting-mpe-wiki/32/4
• https://www.keithmcmillen.com/matrix/#software
• https://www.idesignsound.com/best-mpe-vst-synths-samplers-effects/