| 64 | #if MY_PITCHSHIFTER |
| 65 | |
| 66 | void PitchShifter::Process(float* buffer, int bufferSize) |
| 67 | { |
| 68 | PROFILER(PitchShifter); |
| 69 | |
| 70 | const int osamp = mOversampling; |
| 71 | const int stepSize = mFFTBins / osamp; |
| 72 | const double expct = 2. * M_PI * (double)stepSize / (double)mFFTBins; |
| 73 | const double freqPerBin = gSampleRate / (double)mFFTBins; |
| 74 | |
| 75 | mLatency = mFFTBins - stepSize; |
| 76 | |
| 77 | mRollingInputBuffer.WriteChunk(buffer, bufferSize, 0); |
| 78 | |
| 79 | //copy rolling input buffer into working buffer and window it |
| 80 | mRollingInputBuffer.ReadChunk(mFFTData.mTimeDomain, mFFTBins, latency); |
| 81 | Mult(mFFTData.mTimeDomain, mWindower, mFFTBins); |
| 82 | |
| 83 | mFFT.Forward(mFFTData.mTimeDomain, |
| 84 | mFFTData.mRealValues, |
| 85 | mFFTData.mImaginaryValues); |
| 86 | |
| 87 | const int fftFrameSize2 = mFFTBins / 2; |
| 88 | |
| 89 | // this is the analysis step |
| 90 | for (int k = 0; k <= fftFrameSize2; k++) |
| 91 | { |
| 92 | // de-interlace FFT buffer |
| 93 | float real = mFFTData.mRealValues[k]; |
| 94 | float imag = mFFTData.mImaginaryValues[k]; |
| 95 | |
| 96 | // compute magnitude and phase |
| 97 | double mag = 2. * sqrt(real * real + imag * imag); |
| 98 | double phase = atan2(imag, real); |
| 99 | |
| 100 | // compute phase difference |
| 101 | double diff = phase - mLastPhase[k]; |
| 102 | mLastPhase[k] = phase; |
| 103 | |
| 104 | // subtract expected phase difference |
| 105 | diff -= (double)k * expct; |
| 106 | |
| 107 | // map delta phase into +/- Pi interval |
| 108 | long qpd = diff / M_PI; |
| 109 | if (qpd >= 0) |
| 110 | qpd += qpd & 1; |
| 111 | else |
| 112 | qpd -= qpd & 1; |
| 113 | diff -= M_PI * (double)qpd; |
| 114 | |
| 115 | // get deviation from bin frequency from the +/- Pi interval |
| 116 | double deviation = osamp * diff / (2. * M_PI); |
| 117 | |
| 118 | // compute the k-th partials' true frequency |
| 119 | double freq = (double)k * freqPerBin + deviation * freqPerBin; |
| 120 | |
| 121 | // store magnitude and true frequency in analysis arrays |
| 122 | mAnalysisMag[k] = mag; |
| 123 | mAnalysisFreq[k] = freq; |