FFT不精确C＃

byte[] buffer = new byte[8192];
int bytesRead;
do
{
  bytesRead = stream16.Read(buffer, 0, buffer.Length);
} while (bytesRead != 0);

public int Read(byte[] buffer, int offset, int bytesRead)
{
  int frames = bytesRead / sizeof(float);
  float pitch = DetectPitch(waveBuffer.FloatBuffer, frames);
}

private float DetectPitch(float[] buffer, int inFrames)
{
  Func<int, int, float> window = HammingWindow;
  if (prevBuffer == null)
  {
    prevBuffer = new float[inFrames]; //only contains zeroes
  }  

  // 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
     }
   }
   SmbPitchShift.smbFft(fftBuffer, frames, -1);
  }

float binSize = sampleRate / frames;
int minBin = (int)(82.407 / binSize); //lowest E string on the guitar
int maxBin = (int)(1244.508 / binSize); //highest E string on the guitar

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;