Hum, sing, or play a single-line melody — from the mic or an audio file — and get
back a Standard MIDI File (.mid) of the notes. It tracks the pitch with the tuner's
detector, decides where each note begins and ends, and writes them out. This is
monophonic: one note at a time (a voice, a flute, a bassline) — chords and full
mixes are out of scope. Everything runs here; nothing is uploaded.