public void CopyValues(CamdPitchCandidate other)
{
halftone = other.halftone;
error = other.error;
normalizedError = other.normalizedError;
normalizedErrorWithBias = other.normalizedErrorWithBias;
}
public CamdAudioSamplesAnalyzer(int sampleRateHz, int maxSampleLength)
{
this.maxSampleLength = maxSampleLength;
float[] halftoneFrequencies = MidiUtils.PrecalculateHalftoneFrequencies(MinNote, NumHalftones);
halftoneDelays = MidiUtils.PrecalculateHalftoneDelays(sampleRateHz, halftoneFrequencies);
for (int i = 0; i < currentCandidates.Length; i++)
{
currentCandidates[i] = new CamdPitchCandidate();
}
}
private void FindBestCandidate(CamdPitchCandidate[] currentCandidates, CircularBuffer <CamdPitchCandidate> bestCandidateHistory)
{
bestCurrentCandidate = null;
currentCandidates.ForEach((currentCandidate) =>
{
// Bias towards recently detected pitches.
// For candidates with similar normalizedError,
// this will prefer a candidate that has been detected before, which reduces the "jitter" of the pitch detection.
// However, if a new pitch has been clearly identified with significantly less normalizedError,
// then an old detected pitch from the history will not be used instead because its normalizedError will still be less - even without bias.
currentCandidate.normalizedErrorWithBias = currentCandidate.normalizedError;
if (HalftoneContinuationBias >= 0 && HalftoneContinuationBias <= 1)
{
for (int historyIndex = 0; historyIndex < bestCandidateHistory.Size; historyIndex++)
{
if (bestCandidateHistory[historyIndex].halftone == currentCandidate.halftone)
{
// The further away in the history the halftone was before, the less the bias will impact the current candidate.
float biasConsideringHistoryDistance = HalftoneContinuationBias - (HalftoneContinuationBias * (historyIndex / bestCandidateHistory.Size));
currentCandidate.normalizedErrorWithBias = currentCandidate.normalizedError * (1 - biasConsideringHistoryDistance);
// Do not apply bias multiple times.
break;
}
}
}
if (currentCandidate.halftone >= 0 &&
(bestCurrentCandidate == null ||
bestCurrentCandidate.halftone < 0 ||
currentCandidate.normalizedErrorWithBias < bestCurrentCandidate.normalizedErrorWithBias))
{
bestCurrentCandidate = currentCandidate;
}
});
CamdPitchCandidate bestHistoryCandidate = null;
for (int i = 0; i < bestCandidateHistory.Size; i++)
{
// Do not consider the biased error when comparing best candidate from history.
CamdPitchCandidate historyCandidate = bestCandidateHistory[i];
if (historyCandidate.halftone >= 0 &&
(bestHistoryCandidate == null ||
bestHistoryCandidate.halftone < 0 ||
historyCandidate.normalizedError < bestHistoryCandidate.normalizedError))
{
bestHistoryCandidate = historyCandidate;
}
}
// Do not consider the biased error when comparing best candidate from history.
bestCandidate = (bestHistoryCandidate == null || bestCurrentCandidate.normalizedErrorWithBias < bestHistoryCandidate.normalizedError)
? bestCurrentCandidate
: bestHistoryCandidate;
}
public CamdPitchCandidate(CamdPitchCandidate other)
{
CopyValues(other);
}