public BeatTracker(BeatTracker tracker)
{
Interval = tracker.Interval;
NextPrediction = tracker.NextPrediction;
ProcessedItems = new List <BeatEvent>(tracker.ProcessedItems);
Rating = tracker.Rating;
OriginalScore = tracker.OriginalScore;
}
static void Main(string[] args)
{
bool edit_only = false;
bool find_hierarchy = true;
if (!edit_only)
{
MidiReader reader = new MidiReader();
Console.WriteLine("Ready to record. Press any key to begin.");
Console.ReadKey();
reader.Start();
Console.WriteLine("Recording started. Press any key to stop the recording.");
Console.ReadKey();
reader.Stop();
Console.WriteLine("Recording finished. Processing...");
List <BeatEvent> beatEvents = TempoInferrer.NotesToEvents(reader.FetchEventList());
List <IntervalCluster> intervalClusters = TempoInferrer.EventsToClusters(beatEvents);
intervalClusters = TempoInferrer.RateClusters(intervalClusters);
BeatTracker finalBeat = BeatInferrer.FindBeat(intervalClusters, beatEvents);
RhythmStructure rhythm = RhythmCreator.CreateRhythm(finalBeat, beatEvents);
if (find_hierarchy)
{
rhythm = HierarchicalRhythmInferrer.FindRepeatingUnit(rhythm);
}
AsciiTabRenderer.RenderAsciiTab(rhythm);
Console.WriteLine("ASCII Tab rendered to tab.txt.");
if (find_hierarchy)
{
HierarchicalRhythm hRhythm = HierarchicalRhythmInferrer.CreateHierarchicalRhythm(rhythm);
hRhythm.Print();
}
}
/* Read in (possibly edited) ASCII tab and convert to Sonic Pi */
SonicPiEmitter.EmitSonicPi();
Console.WriteLine("Sonic Pi code emitted to sonicpi.txt");
Console.ReadKey();
}
/* Create a rhythm from a tracker and list of events, by quantizing the events
* according to the beat tracker given to the function. */
public static RhythmStructure CreateRhythm(BeatTracker tracker, List <BeatEvent> events)
{
const byte numDivisions = 4;
int eventIndex = 0;
RhythmStructure rhythm = new RhythmStructure(tracker.Interval);
/* Iterate over all the beats and semiquavers, and set the semiquaver interval. */
for (int i = 0; i < tracker.ProcessedItems.Count; i++)
{
BeatEvent baseEvent = tracker.ProcessedItems[i];
double interval;
if (i != tracker.ProcessedItems.Count - 1)
{
BeatEvent nextEvent = tracker.ProcessedItems[i + 1];
interval = (nextEvent.Time - baseEvent.Time) / 4;
}
else
{
interval = (tracker.NextPrediction - baseEvent.Time) / 4;
}
for (int j = 0; j < numDivisions; j++)
{
HashSet <Drum> drums = new HashSet <Drum>();
/* Determine the time at which one semiquaver event occurs and then quantizes each note event to the semiquaver. */
double baseTime = baseEvent.Time + (j * interval);
if (eventIndex < events.Count && baseTime - (interval / 2) < events[eventIndex].Time && baseTime + (interval / 2) > events[eventIndex].Time)
{
foreach (NoteEvent noteEvent in events[eventIndex].Notes)
{
if (indexToDrum.Keys.Contains(noteEvent.Channel))
{
Drum drum = indexToDrum[noteEvent.Channel];
drums.Add(drum);
}
}
eventIndex++;
}
rhythm.AddDrums(drums);
}
}
return(rhythm);
}
public static BeatTracker FindBeat(List <IntervalCluster> tempoHypotheses, List <BeatEvent> events)
{
/* First, create all the trackers. */
List <BeatTracker> trackers = new List <BeatTracker>();
for (int i = 0; i < tempoHypotheses.Count; i++)
{
IntervalCluster cluster = tempoHypotheses[i];
foreach (BeatEvent startEvent in events.Where(e => e.Time < initialPeriod).ToList())
{
trackers.Add(new BeatTracker(cluster.MeanLength, startEvent, cluster.Rating));
}
}
/* Iterate through every event in the rhythm, processing each tracker. */
foreach (BeatEvent _event in events)
{
List <BeatTracker> newTrackers = new List <BeatTracker>();
for (int i = trackers.Count - 1; i >= 0; i--)
{
/* If any tracker has gone too long without detecting a beat candidate, drop it. */
BeatTracker tracker = trackers[i];
if (_event.Time - tracker.ProcessedItems[tracker.ProcessedItems.Count - 1].Time > maximumInterval)
{
trackers.RemoveAt(i);
}
else
{
/* Catch the trackers up with the current event. */
while (tracker.NextPrediction + (outerWindowFactor * tracker.Interval) < _event.Time)
{
tracker.NextPrediction += tracker.Interval;
}
/* Check whether the event is a feasible beat time. */
if (_event.Time > tracker.NextPrediction - (outerWindowFactor * tracker.Interval) &&
(_event.Time < tracker.NextPrediction + (outerWindowFactor * tracker.Interval)))
{
/* If it's too close to be sure, create another tracker. */
if (Math.Abs(_event.Time - tracker.NextPrediction) > innerWindow)
{
newTrackers.Add(new BeatTracker(tracker));
}
/* Update the tracker to prepare for the next loop iteration. */
double error = _event.Time - tracker.NextPrediction;
tracker.Interval += error * correctionFactor;
tracker.NextPrediction = _event.Time + tracker.Interval;
tracker.ProcessedItems.Add(_event);
// NOTE: It might be useful to have drum specific stuff as well as velocity
tracker.Rating += (1 - (Math.Abs(error) / (2 * tracker.NextPrediction))) * _event.Notes.Sum(n => n.Velocity);
}
}
}
// Add new trackers to the list
foreach (BeatTracker tracker in newTrackers)
{
trackers.Add(tracker);
}
// Remove duplicate trackers
List <BeatTracker> nextTrackers = new List <BeatTracker>();
foreach (BeatTracker tracker in trackers)
{
bool matchFound = false;
foreach (BeatTracker nextTracker in nextTrackers)
{
if (!matchFound && SimilarTrackers(tracker, nextTracker))
{
nextTracker.TakeBestTracker(tracker);
matchFound = true;
}
}
if (!matchFound)
{
nextTrackers.Add(tracker);
}
}
trackers = nextTrackers;
}
/* Weight each tracker's rating by the original score, so as to avoid very short beat selections. */
foreach (BeatTracker tracker in trackers)
{
tracker.Rating *= tracker.OriginalScore;
}
trackers = trackers.OrderByDescending(t => t.Rating).ToList();
// TODO: There are a lot of trackers that appear to be duplicates. Investigate.
for (int i = 0; i < Math.Min(trackers.Count, 10); i++)
{
trackers[i].PrintTracker();
}
return(trackers[0]);
}
/* Fuzzy comparison of trackers, since they can be non-identical but functionally the same. */
static bool SimilarTrackers(BeatTracker first, BeatTracker second)
{
return((Math.Abs(first.Interval - second.Interval) < 10) && (Math.Abs(first.NextPrediction - second.NextPrediction) < 20));
}
