public float DetectPitch(float[] buffer, int inFrames)
{
Func <int, int, float> window = HammingWindow;
if (prevBuffer == null)
{
prevBuffer = new float[inFrames];
}
// double frames since we are combining present and previous buffers
int frames = inFrames * 2;
if (fftBuffer == null)
{
fftBuffer = new float[frames * 2]; // times 2 because it is complex input
}
for (int n = 0; n < frames; n++)
{
if (n < inFrames)
{
fftBuffer[n * 2] = prevBuffer[n] * window(n, frames);
fftBuffer[n * 2 + 1] = 0; // need to clear out as fft modifies buffer
}
else
{
fftBuffer[n * 2] = buffer[n - inFrames] * window(n, frames);
fftBuffer[n * 2 + 1] = 0; // need to clear out as fft modifies buffer
}
}
// assuming frames is a power of 2
SmbPitchShift.smbFft(fftBuffer, frames, -1);
float binSize = sampleRate / frames;
int minBin = (int)(85 / binSize);
int maxBin = (int)(300 / binSize);
float maxIntensity = 0f;
int maxBinIndex = 0;
for (int bin = minBin; bin <= maxBin; bin++)
{
float real = fftBuffer[bin * 2];
float imaginary = fftBuffer[bin * 2 + 1];
float intensity = real * real + imaginary * imaginary;
if (intensity > maxIntensity)
{
maxIntensity = intensity;
maxBinIndex = bin;
}
}
return(binSize * maxBinIndex);
}
public void ShiftPitch(float[] inputBuff, float inputPitch, float targetPitch, float[] outputBuff, int nFrames)
{
UpdateSettings();
detectedPitch = inputPitch;
float shiftFactor = 1.0f;
if (this.settings.SnapMode)
{
if (inputPitch > 0)
{
shiftFactor = snapFactor(inputPitch);
shiftFactor += addVibrato(nFrames);
}
}
else
{
float midiPitch = targetPitch;
shiftFactor = 1.0f;
if (inputPitch > 0 && midiPitch > 0)
{
shiftFactor = midiPitch / inputPitch;
}
}
if (shiftFactor > 2.0)
{
shiftFactor = 2.0f;
}
if (shiftFactor < 0.5)
{
shiftFactor = 0.5f;
}
// fftFrameSize was nFrames but can't guarantee it is a power of 2
// 2048 works, let's try 1024
int fftFrameSize = 2048;
int osamp = 8; // 32 is best quality
SmbPitchShift.smbPitchShift(shiftFactor, nFrames, fftFrameSize, osamp, this.sampleRate, inputBuff, outputBuff);
//vibrato
//addVibrato(outputBuff, nFrames);
shiftedPitch = inputPitch * shiftFactor;
updateShifts(detectedPitch, shiftedPitch, this.currPitch);
}
