public static List <MidiNote> GetNotes(Sequence sequence)
{
sequencer.Sequence = sequence;
List <MidiNote> notes = new List <MidiNote>();
foreach (Track track in sequence)
{
// Scan all of the notes
for (int i = 0; i < track.Count; i++)
{
MidiEvent midiEvent = track.GetMidiEvent(i);
if (midiEvent.MidiMessage.MessageType == MessageType.Channel)
{
var message = midiEvent.MidiMessage as ChannelMessage;
if (message.Data2 > 0 && message.Command == ChannelCommand.NoteOn)
{
MidiNote note = CreateNote(track, midiEvent, i);
notes.Add(note);
}
}
}
}
notes.Sort((a, b) => a.Start.CompareTo(b.Start));
return(SplitNotes(notes));
}
private static MidiNote CreateNote(Track track, MidiEvent startEvent, int i)
{
MidiEvent endEvent = FindNoteOff(track, startEvent, i);
ChannelMessage start = startEvent.MidiMessage as ChannelMessage;
ChannelMessage end = endEvent.MidiMessage as ChannelMessage;
MidiNote midiNote = new MidiNote();
float volume = Math.Min(1f, start.Data2 / 127f);
midiNote.Note = new MusicNote(Math.Max(0, start.Data1 - 12)); //, volume);
midiNote.Start = TimeSpan.FromMilliseconds(sequencer.TicksToMilliseconds(startEvent.AbsoluteTicks));
if (end == null)
{
midiNote.Duration = TimeSpan.FromMilliseconds(sequencer.TicksToMilliseconds(track.Length)) - midiNote.Start;
}
else
{
midiNote.Duration = TimeSpan.FromMilliseconds(sequencer.TicksToMilliseconds(endEvent.AbsoluteTicks)) - midiNote.Start;
}
return(midiNote);
}
private static List <MidiNote> SplitNotes(List <MidiNote> inputNotes)
{
List <MidiNote> outputNotes = new List <MidiNote>();
//Dictionary<int, MidiNote> playingNotes = new Dictionary<int, MidiNote>();
MidiNote lastNote = new MidiNote();
for (int i = 0; i < inputNotes.Count; i++)
{
MidiNote note = inputNotes[i];
/*foreach (var pair in playingNotes.ToArray()) {
* int index = pair.Key;
* MidiNote pNote = pair.Value;
* if (note.Start >= pNote.End) {
* playingNotes.Remove(index);
* }
* else {
* outputNotes[index].End = note.Start;
* }
* }*/
if (i != 0 && lastNote.End > note.Start)
{
lastNote.End = note.Start;
outputNotes[outputNotes.Count - 1] = lastNote;
}
//playingNotes.Add(i, note);
outputNotes.Add(note);
}
for (int i = 0; i < outputNotes.Count; i++)
{
MidiNote note = outputNotes[i];
if (note.Duration <= TimeSpan.Zero)
{
outputNotes.RemoveAt(i);
i--;
}
}
return(outputNotes);
}
private static void WriteNote(BinaryWriter writer, MidiNote note, PCMModifiers mods)
{
// Square wave
MusicNote musicNote = note.Note;
musicNote.Octave += mods.OctaveOffset;
musicNote.Octave = Math.Max(mods.MaxOctave, musicNote.Octave);
int max = (int)Math.Round(sbyte.MaxValue * note.Note.Volume * mods.Volume);
int min = (int)Math.Round(sbyte.MinValue * note.Note.Volume * mods.Volume);
int range = max - min;
//int halfRange = range / 2;
float freq = note.Note.Frequency;
float period = mods.SampleRate / freq;
int start = (int)Math.Round(note.Start.TotalSeconds * mods.SampleRate);
int length = (int)Math.Round(note.Duration.TotalSeconds * mods.SampleRate);
writer.BaseStream.Position = start;
bool up = true;
int inc = (int)Math.Round(period / 2);
int next = inc;
for (int i = 0; i < length; i++)
{
int sample;
float dif = next - i;
if (dif <= 0)
{
up = !up;
next += inc;
//dif++;
dif++;
}
if (dif >= 1)
{
if (up)
{
sample = max;
}
else
{
sample = min;
}
}
else
{
if (up != (dif >= 0.5f))
{
sample = max;
}
else
{
sample = min;
}
/*if (up)
* sample = (int) (max - range * dif);
* else
* sample = (int) (min + range * dif);*/
}
writer.Write(unchecked ((byte)(sample & 0xFF)));
}
}
