// Turns a channel event into a musical note object.
public Note EventToNote(ChannelEvent eventIn)
{
Note note = new Note();
note.SetPitch((NotePitch)eventIn.GetParam1());
note.SetVelocity(eventIn.GetParam2());
note.SetChannel(eventIn.GetChannel());
return(note);
}
public void ParseEvents()
{
Dictionary <NotePitch, Stack <Note> > activeNotes = new Dictionary <NotePitch, Stack <Note> >(); // Dictionary of all notes that have a NoteOn but no NoteOff.
uint timeElapsed = 0;
for (int i = 0; i < midiEvents.Count; i++)
{
Event tempEvent = midiEvents.ElementAt(i);
timeElapsed += tempEvent.GetTime();
switch (tempEvent.GetEventType())
{
case MidiEventType.NoteOn:
ChannelEvent tempNoteOnEvent = (ChannelEvent)tempEvent;
Note currentNoteOn = EventToNote(tempNoteOnEvent);
currentNoteOn.SetTime(timeElapsed);
// If there is already an active note in this pitch, add the new note to the existing stack.
if (activeNotes.ContainsKey(currentNoteOn.GetPitch()))
{
activeNotes[currentNoteOn.GetPitch()].Push(currentNoteOn);
}
else // If there is no active note in this pitch, create the stack and then add the note.
{
Stack <Note> notesStack = new Stack <Note>();
notesStack.Push(currentNoteOn);
activeNotes.Add(currentNoteOn.GetPitch(), notesStack);
}
break;
case MidiEventType.NoteOff:
ChannelEvent tempNoteOffEvent = (ChannelEvent)tempEvent;
Note currentNoteOff = EventToNote(tempNoteOffEvent);
// If there is already at least one active note in this pitch, pop the latest one and finalise its duration.
if (activeNotes.ContainsKey(currentNoteOff.GetPitch()))
{
Note tempNote = activeNotes[currentNoteOff.GetPitch()].Pop();
tempNote.SetDuration(timeElapsed - tempNote.GetTime());
notes.Add(tempNote);
if (activeNotes[currentNoteOff.GetPitch()].Count == 0) // If the stack of notes is empty, remove the entry from the dictionary of active notes.
{
activeNotes.Remove(currentNoteOff.GetPitch());
}
}
else // If there was a note off event at a certain pitch with no note on events at that pitch.
{
throw new InvalidOperationException("Note off without corresponding note on.");
}
break;
case MidiEventType.SetTempo:
bpm = CalculateBPM(((NumMetaEvent)tempEvent).GetNum());
break;
case MidiEventType.TimeSignature:
timeSig = CalculateTimeSignature(((NumMetaEvent)tempEvent).GetNum());
break;
case MidiEventType.EndOfTrack:
midiLength = timeElapsed > midiLength ? timeElapsed : midiLength;
timeElapsed = 0;
break;
}
}
}
private int ParseChannelEvent(int index, uint time, byte type)
{
uint channel = (uint)(type & 0x0F);
MidiEventType eventType = (MidiEventType)(type & 0xF0);
ChannelEvent channelEvent = new ChannelEvent();
channelEvent.SetChannel(channel);
channelEvent.SetTime(time);
channelEvent.SetEventType(eventType);
Console.WriteLine("--- Channel: " + channel);
Console.WriteLine("--- Time: " + time);
Console.WriteLine("--- Event Type: " + eventType);
byte param1;
byte param2;
switch (eventType)
{
case MidiEventType.NoteOn:
param1 = midi[index++];
param2 = midi[index++];
channelEvent.SetParam1(param1);
channelEvent.SetParam2(param2);
if (param2 == 0)
{
channelEvent.SetEventType(MidiEventType.NoteOff);
}
Console.WriteLine("--- Note: " + param1);
Console.WriteLine("--- Velocity: " + param2);
break;
case MidiEventType.NoteOff:
param1 = midi[index++];
param2 = midi[index++];
channelEvent.SetParam1(param1);
channelEvent.SetParam2(param2);
Console.WriteLine("--- Note: " + param1);
Console.WriteLine("--- Velocity: " + param2);
break;
case MidiEventType.NoteAftertouch:
param1 = midi[index++];
param2 = midi[index++];
channelEvent.SetParam1(param1);
channelEvent.SetParam2(param2);
Console.WriteLine("--- Note: " + param1);
Console.WriteLine("--- Amount: " + param2);
break;
case MidiEventType.Controller:
param1 = midi[index++];
param2 = midi[index++];
channelEvent.SetParam1(param1);
channelEvent.SetParam2(param2);
Console.WriteLine("--- Controller: " + param1);
Console.WriteLine("--- Value: " + param2);
break;
case MidiEventType.ProgramChange:
param1 = midi[index++];
channelEvent.SetParam1(param1);
Console.WriteLine("--- Program: " + param1);
break;
case MidiEventType.ChannelAftertouch:
param1 = midi[index++];
channelEvent.SetParam1(param1);
Console.WriteLine("--- Amount: " + param1);
break;
case MidiEventType.PitchBend:
param1 = midi[index++];
param2 = midi[index++];
channelEvent.SetParam1(param1);
channelEvent.SetParam2(param2);
Console.WriteLine("--- LSB Value: " + param1);
Console.WriteLine("--- MSB Value: " + param2);
break;
default:
return(-1);
}
midiEvents.Add(channelEvent);
return(index);
}
