private long GetAbsoluteTime(double startTime)
{
TempoIndex currentTempo = _tempoIdx.First();
// Finds last tempo change before event
foreach (TempoIndex idx in _tempoIdx.Skip(1))
{
if (idx.RealTime <= startTime)
{
currentTempo = idx;
}
else
{
break;
}
}
double difference = startTime - currentTempo.RealTime;
long absoluteTicks = currentTempo.AbsoluteTime + (1000L * (long)difference * DELTA_TICKS_PER_QUARTER) / currentTempo.MicroPerQuarter;
// Applies quantization and snaps to grid
int q = DELTA_TICKS_PER_QUARTER / 32; // 1/128th quantization
if (absoluteTicks % q != 0)
{
long before = absoluteTicks % q;
long after = q - before;
if (before < after)
{
absoluteTicks -= before;
}
else
{
absoluteTicks += after;
}
}
return(absoluteTicks);
}
private List <MidiEvent> CreateTempoTrack(Tempo tempo, TimeSignature ts)
{
List <MidiEvent> track = new List <MidiEvent>();
_tempoIdx.Clear();
track.Add(new NAudio.Midi.TextEvent("bfTempo", MetaEventType.SequenceTrackName, 0));
if (tempo.Events.Count <= 0 || tempo.Events[0].Start > 0.0f)
{
var idxEntry = new TempoIndex(0, 0, 120);
//track.Add(new NAudio.Midi.TempoEvent(idxEntry.MicroPerQuarter, idxEntry.AbsoluteTime));
_tempoIdx.Add(idxEntry);
}
long GetAbsoluteTime(double startTime, TempoIndex currentTempo)
{
double difference = startTime - currentTempo.RealTime;
long absoluteTicks = currentTempo.AbsoluteTime + (1000L * (long)difference * DELTA_TICKS_PER_QUARTER) / currentTempo.MicroPerQuarter;
//int q = DELTA_TICKS_PER_QUARTER / 32; // 1/128th quantization
//if (absoluteTicks % q != 0) absoluteTicks += q - (absoluteTicks % q);
// Applies quantization and snaps to grid
int q = DELTA_TICKS_PER_QUARTER / 32; // 1/128th quantization
if (absoluteTicks % q != 0)
{
long before = absoluteTicks % q;
long after = q - before;
if (before < after)
{
absoluteTicks -= before;
}
else
{
absoluteTicks += after;
}
}
return(absoluteTicks);
}
// Adds tempo changes
if (tempo.Events.Count > 0)
{
var firstTempo = tempo.Events.First();
var idxEntry = new TempoIndex()
{
AbsoluteTime = _tempoIdx.Count > 0 ? GetAbsoluteTime(firstTempo.Start, _tempoIdx.Last()) : 0,
RealTime = firstTempo.Start,
BPM = firstTempo.BPM
};
track.Add(new NAudio.Midi.TempoEvent(idxEntry.MicroPerQuarter, idxEntry.AbsoluteTime));
_tempoIdx.Add(idxEntry);
foreach (var tempoEntry in tempo.Events.Skip(1))
{
idxEntry = new TempoIndex()
{
AbsoluteTime = GetAbsoluteTime(tempoEntry.Start, _tempoIdx.Last()),
RealTime = tempoEntry.Start,
BPM = tempoEntry.BPM
};
track.Add(new NAudio.Midi.TempoEvent(idxEntry.MicroPerQuarter, idxEntry.AbsoluteTime));
_tempoIdx.Add(idxEntry);
}
}
// Adds time signature changes
foreach (var time in ts.Events)
{
int den = (int)Math.Log(time.Measure, 2);
track.Add(new TimeSignatureEvent(this.GetAbsoluteTime(time.Start), time.Beat, den, 24, 8));
}
// Sort by absolute time (And ensure track name is first event)
track.Sort((x, y) => (int)(x is NAudio.Midi.TextEvent ? int.MinValue : x.AbsoluteTime - y.AbsoluteTime));
// Adds end track
track.Add(new MetaEvent(MetaEventType.EndTrack, 0, track.Last().AbsoluteTime));
return(track);
}
