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// Convert the input structure to a more useful structure where each item has a length of its own.
var instrumentIndexToName = require('./instrument-index-to-name');
var createNoteMap = function(sequence) {
var map = [];
for (var i = 0; i < sequence.tracks.length; i++)
map.push([]);
// TODO-PER: handle more than one note in a track
var nextNote = {};
var currentInstrument = instrumentIndexToName[0];
// ev.start and ev.duration are in whole notes. Need to turn them into
sequence.tracks.forEach(function(track, i) {
track.forEach(function(ev) {
switch (ev.cmd) {
case "note":
// ev contains:
// {"cmd":"note","pitch":72,"volume":95,"start":0.125,"duration":0.25,"instrument":0,"gap":0}
// where start and duration are in whole notes, gap is in 1/1920 of a second (i.e. MIDI ticks)
var inst = ev.instrument !== undefined ? instrumentIndexToName[ev.instrument] : currentInstrument
if (ev.duration > 0) {
var gap = ev.gap ? ev.gap : 0;
var len = ev.duration;
gap = Math.min(gap, len * 2 / 3);
var obj = {
pitch: ev.pitch,
instrument: inst,
start: Math.round((ev.start) * 1000000)/1000000,
end: Math.round((ev.start + len - gap) * 1000000)/1000000,
volume: ev.volume
};
if (ev.startChar)
obj.startChar = ev.startChar;
if (ev.endChar)
obj.endChar = ev.endChar;
if (ev.style)
obj.style = ev.style;
if (ev.cents)
obj.cents = ev.cents;
map[i].push(obj);
}
break;
case "program":
currentInstrument = instrumentIndexToName[ev.instrument];
break;
case "text":
// Ignore the track names - that is just for midi files.
break;
default:
// TODO-PER: handle other event types
console.log("Unhandled midi event", ev);
}
});
});
return map;
};
module.exports = createNoteMap;
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