private void UpdateEvent(AudioDetectorType type, double significance)
{
this.eventBuffer.AddOrUpdate(
type,
audioDetectorType => {
return(new AudioEvent()
{
type = audioDetectorType,
significance = significance,
});
},
(audioDetectorType, existingAudioEvent) => {
existingAudioEvent.significance = Math.Max(
existingAudioEvent.significance,
significance
);
return(existingAudioEvent);
}
);
}
private void UpdateEnergyHistory()
{
var energyLevels = new Dictionary <AudioDetectorType, double>();
foreach (var key in bins.Keys)
{
energyLevels[key] = 0.0;
}
for (int i = 1; i < this.AudioData.Length / 2; i++)
{
foreach (var pair in bins)
{
AudioDetectorType type = pair.Key;
double[] window = pair.Value;
if (WindowContains(window, i))
{
energyLevels[type] += this.AudioData[i] * this.AudioData[i];
}
}
}
foreach (var type in bins.Keys)
{
double current = energyLevels[type];
double[] history = this.energyHistory[type];
double previous = history[
(this.currentHistoryOffset + historyLength - 1) % historyLength
];
double change = current - previous;
double avg = history.Average();
double max = history.Max();
double ssd = history.Select(val => (val - avg) * (val - avg)).Sum();
double sd = Math.Sqrt(ssd / historyLength);
double stdsFromAverage = (current - avg) / sd;
if (type == AudioDetectorType.Kick)
{
if (
current > max &&
stdsFromAverage > this.config.kickT &&
avg < this.config.kickQ &&
current > .001
)
{
double significance = Math.Atan(
stdsFromAverage / (this.config.kickT + 0.001)
) * 2 / Math.PI;
this.UpdateEvent(type, significance);
}
}
else if (type == AudioDetectorType.Snare)
{
if (
current > max &&
stdsFromAverage > this.config.snareT &&
avg < this.config.snareQ &&
current > .001
)
{
double significance = Math.Atan(
stdsFromAverage / (this.config.snareT + 0.001)
) * 2 / Math.PI;
this.UpdateEvent(type, significance);
}
}
}
foreach (var type in bins.Keys)
{
this.energyHistory[type][this.currentHistoryOffset] =
energyLevels[type];
}
this.currentHistoryOffset = (this.currentHistoryOffset + 1)
% historyLength;
}
