Playback

[1j01]

As long as this doesn't complicate the app too much, it'd be nice to be able to play back recordings, for these reasons:

• In case you don't have software installed to play MIDI files (such as VLC, configured with a downloaded soundfont)
• If it's easier to use than such software, due to the convenience of being built-in
• To use the visualization to render video after-the-fact
  • Most playback software doesn't support MIDI visualization, especially of pitch bends.
  • This would be an easier workflow for video production than recording live, as it's hard to get the timings all lined up without latency, especially if you want notes to fall down onto the piano, rather than going out from the piano, which requires a screen's worth of latency for the notes to fall down, or magical future-prediction powers.

What this might look like:
I could add a "MIDI file playback" heading and file selector to the Input section, but there would need to be controls for pausing/playing, stopping, seeking, zooming, and volume adjustment; and those aren't "input" in the same way; they aren't MIDI data sources.
So I might need a new "Playback" section, at which point it might make sense to have the file input there, I'm not sure.
There should also be a way to play back what you just recorded (without saving and loading a file). Naturally playback can work using the recording, until you load a file, but should it automatically revert to using the recording buffer if you play notes? My gut says no, since you could have a MIDI device sending a reset signal before automatically powering off, which shouldn't interrupt your listening; or you could want to play along with a recording, to make a second part. Maybe if playback is finished, though, it should reset.
And there would need to be a soundfont / playback engine. There are libraries for this part.

Alternatively I could make a separate app for playing MIDI files, reusing the MIDI visualization between apps. This wouldn't have the convenience advantage of built-in playback, unless there's some linking/communication between the apps.