/** Parse the given Midi file, and return an instance of this MidiFile
* class. After reading the midi file, this object will contain:
* - The raw list of midi events
* - The Time Signature of the song
* - All the tracks in the song which contain notes.
* - The number, starttime, and duration of each note.
*/
public void parse(MidiFileReader file, string filename)
{
string id;
int len;
this.filename = filename;
tracks = new List<MidiTrack>();
trackPerChannel = false;
id = file.ReadAscii(4);
if (id != "MThd") {
throw new MidiFileException("Doesn't start with MThd", 0);
}
len = file.ReadInt();
if (len != 6) {
throw new MidiFileException("Bad MThd header", 4);
}
trackmode = file.ReadShort();
int num_tracks = file.ReadShort();
quarternote = file.ReadShort();
events = new List<MidiEvent>[num_tracks];
for (int tracknum = 0; tracknum < num_tracks; tracknum++) {
events[tracknum] = ReadTrack(file);
MidiTrack track = new MidiTrack(events[tracknum], tracknum);
if (track.Notes.Count > 0) {
tracks.Add(track);
}
}
/* Get the length of the song in pulses */
foreach (MidiTrack track in tracks) {
MidiNote last = track.Notes[track.Notes.Count-1];
if (this.totalpulses < last.StartTime + last.Duration) {
this.totalpulses = last.StartTime + last.Duration;
}
}
/* If we only have one track with multiple channels, then treat
* each channel as a separate track.
*/
if (tracks.Count == 1 && HasMultipleChannels(tracks[0])) {
tracks = SplitChannels(tracks[0], events[tracks[0].Number]);
trackPerChannel = true;
}
CheckStartTimes(tracks);
/* Determine the time signature */
int tempo = 0;
int numer = 0;
int denom = 0;
foreach (List<MidiEvent> list in events) {
foreach (MidiEvent mevent in list) {
if (mevent.Metaevent == MetaEventTempo && tempo == 0) {
tempo = mevent.Tempo;
}
if (mevent.Metaevent == MetaEventTimeSignature && numer == 0) {
numer = mevent.Numerator;
denom = mevent.Denominator;
}
}
}
if (tempo == 0) {
tempo = 500000; /* 500,000 microseconds = 0.05 sec */
}
if (numer == 0) {
numer = 4; denom = 4;
}
timesig = new TimeSignature(numer, denom, quarternote, tempo);
}
public bool useDefaultInstruments; /** If true, don't change instruments */
#endregion Fields
#region Constructors
public MidiOptions(MidiFile midifile)
{
int numtracks = midifile.Tracks.Count;
tracks = new bool[numtracks];
mute = new bool[numtracks];
instruments = new int[numtracks];
for (int i = 0; i < tracks.Length; i++) {
tracks[i] = true;
mute[i] = false;
instruments[i] = midifile.Tracks[i].Instrument;
if (midifile.Tracks[i].InstrumentName == "Percussion") {
tracks[i] = false;
}
}
useDefaultInstruments = true;
scrollVert = true;
largeNoteSize = false;
if (tracks.Length == 1) {
twoStaffs = true;
}
else {
twoStaffs = false;
}
showNoteLetters = NoteNameNone;
showLyrics = true;
showMeasures = false;
shifttime = 0;
transpose = 0;
key = -1;
time = midifile.Time;
colors = null;
shadeColor = Color.FromArgb(210, 205, 220);
shade2Color = Color.FromArgb(80, 100, 250);
combineInterval = 40;
tempo = midifile.Time.Tempo;
pauseTime = 0;
playMeasuresInLoop = false;
playMeasuresInLoopStart = 0;
playMeasuresInLoopEnd = midifile.EndTime() / midifile.Time.Measure;
}
/** In Midi Files, time is measured in pulses. Notes that have
* pulse times that are close together (like within 10 pulses)
* will sound like they're the same chord. We want to draw
* these notes as a single chord, it makes the sheet music much
* easier to read. We don't want to draw notes that are close
* together as two separate chords.
*
* The SymbolSpacing class only aligns notes that have exactly the same
* start times. Notes with slightly different start times will
* appear in separate vertical columns. This isn't what we want.
* We want to align notes with approximately the same start times.
* So, this function is used to assign the same starttime for notes
* that are close together (timewise).
*/
public static void RoundStartTimes(List<MidiTrack> tracks, int millisec, TimeSignature time)
{
/* Get all the starttimes in all tracks, in sorted order */
List<int> starttimes = new List<int>();
foreach (MidiTrack track in tracks) {
foreach (MidiNote note in track.Notes) {
starttimes.Add( note.StartTime );
}
}
starttimes.Sort();
/* Notes within "millisec" milliseconds apart will be combined. */
int interval = time.Quarter * millisec * 1000 / time.Tempo;
/* If two starttimes are within interval millisec, make them the same */
for (int i = 0; i < starttimes.Count - 1; i++) {
if (starttimes[i+1] - starttimes[i] <= interval) {
starttimes[i+1] = starttimes[i];
}
}
CheckStartTimes(tracks);
/* Adjust the note starttimes, so that it matches one of the starttimes values */
foreach (MidiTrack track in tracks) {
int i = 0;
foreach (MidiNote note in track.Notes) {
while (i < starttimes.Count &&
note.StartTime - interval > starttimes[i]) {
i++;
}
if (note.StartTime > starttimes[i] &&
note.StartTime - starttimes[i] <= interval) {
note.StartTime = starttimes[i];
}
}
track.Notes.Sort(track.Notes[0]);
}
}
