How Musescore works?

Thank you so much for the direction. It really helps!

I notice that in midi file.cpp, there's a function that finds chords.

Is it an algorithm published in a research paper?


//---------------------------------------------------------
// findChords
//---------------------------------------------------------

void MidiTrack::findChords()
{
EventList dl;
int n = _events.size();

Drumset* drumset;
if (_drumTrack)
drumset = smDrumset;
else
drumset = 0;
int jitter = 3; // tick tolerance for note on/off

for (int i = 0; i < n; ++i) {
Event* e = _events[i];
if (e == 0)
continue;
if (e->type() != ME_NOTE) {
dl.append(e);
continue;
}

int ontime = e->ontime();
int offtime = e->offtime();
Event* chord = new Event(ME_CHORD);
chord->setOntime(ontime);
chord->setDuration(e->duration());
chord->notes().append(e);
int voice = 0;
chord->setVoice(voice);
dl.append(chord);
_events[i] = 0;

bool useDrumset = false;
if (drumset) {
int pitch = e->pitch();
if (drumset->isValid(pitch)) {
useDrumset = true;
voice = drumset->voice(pitch);
chord->setVoice(voice);
}
}
for (int k = i + 1; k < n; ++k) {
if (_events[k] == 0 || _events[k]->type() != ME_NOTE)
continue;
Event* nn = _events[k];
if (nn->ontime() - jitter > ontime)
break;
if (qAbs(nn->ontime() - ontime) > jitter || qAbs(nn->offtime() - offtime) > jitter)
continue;
int pitch = nn->pitch();
if (useDrumset) {
if (drumset->isValid(pitch) && drumset->voice(pitch) == voice) {
chord->notes().append(nn);
_events[k] = 0;
}
}
else {
chord->notes().append(nn);
_events[k] = 0;
}
}
}
_events = dl;
}