BPM = 60E6 / (No of microseconds per MIDI quarter-note as given by set_tempo meta event)
- Programming MIDI
- http://www.music.mcgill.ca/~ich/classes/mumt306/StandardMIDIfileformat.html
- https://www.fourmilab.ch/webtools/midicsv/
- https://www.cs.cmu.edu/~music/cmsip/readings/davids-midi-spec.htm
- https://github.com/OneLoneCoder/olcPixelGameEngine/blob/master/Videos/OneLoneCoder_PGE_MIDI.cpp
- http://www.gweep.net/~prefect/eng/reference/protocol/midispec.html
- https://www.eecs.umich.edu/courses/eecs373/Lec/StudentF18/MIDI%20Presentation.pdf
- https://stackoverflow.com/questions/2038313/converting-midi-ticks-to-actual-playback-seconds