D:/work/code_by/Wave/pitchlib.cpp

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#include <math.h>
#include <stdlib.h>
#include <string.h>

static const double LOG2 = 0.69314718;

float freqToSmtn(float freq)
{
  return freq <= 0.0f? 0.0f : 69.0 + 12.0 * log(freq / 440.0) / LOG2;
}

float smtnToFreq(int smtn)
{
  return 440.0 * pow(2.0, (smtn - 69) / 12.0);
}

static int round(float f)
{
  return floor(f + 0.5);
}

static float frameFreq(int *frame, int frameSize, int sampleRate)
{
  int i, j, t, sum, threshold;
  int *vec;
  int minIndex[2];

  for (i = 0, j = 0; i < frameSize; i++)
    j += abs(frame[i]);
  if (j < frameSize * 3)  //音量太小
    return 0.0f;

  vec = new int[frameSize];
  t = sampleRate / 1047;  //假設pitch不超過84
  for (i = t - 1, threshold = -1; i < frameSize; i++)
  {
    for (j = frameSize - i - 1, sum = 0; j >= 0; j--)
      sum += abs(frame[j] - frame[j + i]);
    vec[i] = sum;
    if (sum > threshold)
      threshold = sum;
  }
  threshold /= 4;

  for (i = t, j = 0; i < frameSize - 1; i++)
    if (vec[i - 1] >= vec[i] && vec[i] < vec[i + 1] && vec[i] <= threshold)
    {
      minIndex[j++] = i;
      if (j >= 2)
        break;
    }
  delete[] vec;

  if (j == 0)
    return 0.0f;
  if (j == 2)
    if (abs((minIndex[1] - minIndex[0]) * 10 / minIndex[0] - 10) > 1)
      return 0.0f;

  return (float)sampleRate / minIndex[0];
}

static float medianIgnore0(float *vec, int vecSize)
{
  int i, j, k;
  float *vecbak;
  float tmp;

  if (vecSize == 0)
    return 0;
  if (vecSize == 1)
    return vec[0];

  vecbak = new float[vecSize];
  memcpy(vecbak, vec, vecSize * sizeof(float));
  for (i = 0; i < vecSize - 1; i++)
  {
    k = i;
    for (j = i + 1; j < vecSize; j++)
      if (vecbak[j] > vecbak[k])
        k = j;
    if (k != i)
    {
      tmp = vecbak[i];
      vecbak[i] = vecbak[k];
      vecbak[k] = tmp;
    }
  }

  for (i = vecSize - 1; i > 0; i--)
    if (vecbak[i] != 0.0f)
      break;
  tmp = vecbak[i >> 1];
  delete[] vecbak;
  return tmp;
}

static int medianIgnore0(int *vec, int vecSize)
{
  int i, j, k, tmp;
  int *vecbak;

  if (vecSize == 0)
    return 0;
  if (vecSize == 1)
    return vec[0];

  vecbak = new int[vecSize];
  memcpy(vecbak, vec, vecSize * sizeof(int));
  for (i = 0; i < vecSize - 1; i++)
  {
    k = i;
    for (j = i + 1; j < vecSize; j++)
      if (vecbak[j] > vecbak[k])
        k = j;
    if (k != i)
    {
      tmp = vecbak[i];
      vecbak[i] = vecbak[k];
      vecbak[k] = tmp;
    }
  }

  for (i = vecSize - 1; i > 0; i--)
    if (vecbak[i] != 0)
      break;
  tmp = vecbak[i >> 1];
  delete[] vecbak;
  return tmp;
}

void processWave(int *wave, int waveSize)
{
  int i, mean;

  if (waveSize == 0)
    return;

  for (i = 0, mean = 0; i < waveSize; i++)
    mean += wave[i];
  mean /= waveSize;
  if (mean != 0)
    for (i = 0; i < waveSize; i++)
      wave[i] -= mean;
}

int waveToPitch(int *wave, int waveSize, int sampleRate, int pitchRate, float *&fpitch, int *used)
{
  int i, pitchSize;
  int *frame, frameSize, frameStep;

  frameSize = sampleRate / 20;
  frameStep = sampleRate / pitchRate;
  pitchSize = (waveSize - frameSize) / frameStep;
  if (pitchSize <= 0)
  {
    if (used != NULL)
      *used = 0;
    return 0;
  }
  if (used != NULL)
    *used = pitchSize * frameStep;

  if (fpitch == NULL)
    fpitch = new float[pitchSize];
  for (i = 0, frame = wave; i < pitchSize; i++, frame += frameStep)
    fpitch[i] = freqToSmtn(frameFreq(frame, frameSize, sampleRate));

  return pitchSize;
}

void smoothPitch(float *fpitch, int pitchSize, int rate)
{
  int i, w;
  float *pitchbak;

  if (pitchSize < rate)
    return;

  pitchbak = new float[pitchSize];
  memcpy(pitchbak, fpitch, pitchSize * sizeof(float));

  w = rate >> 1;
  fpitch[0] = medianIgnore0(pitchbak, w);
  for (i = 1; i < w; i++)
  {
    fpitch[i] = medianIgnore0(pitchbak, (i << 1) + 1);
    if (fabs(fpitch[i] - fpitch[i - 1]) < 1.0f)
      fpitch[i] = fpitch[i - 1];
    else if (fabs(fpitch[i] - fpitch[i + 1]) >= 1.0f)
      fpitch[i] = fpitch[i - 1];
  }
  for (; i < pitchSize - w; i++)
  {
    fpitch[i] = medianIgnore0(pitchbak + i - w, rate);
    if (fabs(fpitch[i] - fpitch[i - 1]) < 1.0f)
      fpitch[i] = fpitch[i - 1];
    else if (fabs(fpitch[i] - fpitch[i + 1]) >= 1.0f)
      fpitch[i] = fpitch[i - 1];
  }
  for (; i < pitchSize - 1; i++)
  {
    fpitch[i] = medianIgnore0(pitchbak + (i << 1) - pitchSize + 1, ((pitchSize - i) << 1) - 1);
    if (fabs(fpitch[i] - fpitch[i - 1]) < 1.0f)
      fpitch[i] = fpitch[i - 1];
  }
  fpitch[i] = medianIgnore0(pitchbak + pitchSize - w, w);

  delete[] pitchbak;
}

void correctPitch(float *fpitch, int pitchSize, int *pitch)
{
  int i, j, s, shift;
  int whiteSum, maxWhiteSum;
  int white[] = {1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1};

  for (j = shift = 6 * 10, maxWhiteSum = -1; j > -6 * 10; j--)
  {
    for (i = 0, whiteSum = 0; i < pitchSize; i++)
      if (fpitch[i] != 0.0f)
      {
        s = floor(fpitch[i] + (j + 5) / 10.0f);
        whiteSum += white[s % 12];  //白鍵數目和
      }
    if (whiteSum > maxWhiteSum)
    {
      maxWhiteSum = whiteSum;
      shift = j;
    }
  }

  //====================== from Roger
  for (i = 0; i < pitchSize; i++)
  {
    pitch[i] = fpitch[i] == 0.0f? 0 : floor(fpitch[i] + (shift + 5) / 10.0f);
    if (white[pitch[i] % 12] == 0)  //黑鍵要修正
      if (fpitch[i] + shift / 10.0f <= pitch[i])
        --pitch[i];
      else
        ++pitch[i];
  }
  //======================
}
void limitPitch(float *fpitch, int pitchSize, float minPitch, float maxPitch)
{
  int i;

  for (i = 0; i < pitchSize; i++)
    if (fpitch[i] != 0.0f)
      if (fpitch[i] < minPitch)
        fpitch[i] = 0.0f;
      else if (fpitch[i] > maxPitch)
        fpitch[i] = 0.0f;
}

void limitPitch(int *pitch, int pitchSize, int minPitch, int maxPitch)
{
  int i;

  for (i = 0; i < pitchSize; i++)
    if (pitch[i] != 0)
      if (pitch[i] < minPitch)
        pitch[i] = 0;
      else if (pitch[i] > maxPitch)
        pitch[i] = 0;
}


void trimPitch(float *pitch, int pitchSize, int &from, int &to)
{
  for (from = 0; from < pitchSize; from++)
    if (pitch[from] != 0.0f)
      break;
  for (to = pitchSize - 1; to > from; to--)
    if (pitch[to] != 0.0f)
      break;
}
void trimPitch(int *pitch, int pitchSize, int &from, int &to)
{
  for (from = 0; from < pitchSize; from++)
    if (pitch[from] != 0)
      break;
  for (to = pitchSize - 1; to > from; to--)
    if (pitch[to] != 0)
      break;
}

int stairPitch(int *pitch, int pitchSize, int pitchRate, int tempo, int beatsPerMeasure)
{
  int i, from, to, m, count;
  float f;

  if (pitchSize == 0)
    return 0;

  count = pitch[0] == 0? 0 : -1;
  to = 0;
  while (to < pitchSize)
  {
    for (from = to; from < pitchSize; from++)
      if (pitch[from] != 0)
        break;
    if (from == pitchSize)
    {
      ++count;
      break;
    }
    for (to = from + 1; to < pitchSize; to++)
      if (pitch[to] == 0)
        break;

    m = to - from > 0? medianIgnore0(pitch + from, to - from) : 0;
    for (i = from; i < to; i++)
      pitch[i] = m;
    if (m != 0)
      count += 2;
  }

  /*//======================  //from khair
  int pitchPerMeasure = pitchRate * beatsPerMeasure * 60 / tempo;
  for (i = 0; i < pitchSize; i++)
  {
    m = pitch[i] % 12;
    if (m == 1 || m == 3 || m == 6 || m == 8 || m == 10)  //黑鍵，要修正
    {
      from = i / pitchPerMeasure * pitchPerMeasure;
      to = from + pitchPerMeasure - 1;
      if (to >= pitchSize)
        break;

      f = i == from? 0.0f : (float)(pitch[i] - pitch[from]) / (i - from) - (float)(pitch[to] - pitch[from]) / (to - from);
      if (f > 0)
        --pitch[i];
      else if (f < 0)
        ++pitch[i];
      else
      {
        f = (float)(pitch[to] - pitch[from]) / (to - from);
        if (f >= 0)
          ++pitch[i];
        else
          --pitch[i];
      }
    }
  }
  //======================*/

  return count;
}

int pitchToMidi(int *pitch, int pitchSize, int *midi)
{
  int i, from, d;
  int midiSize;

  midiSize = from = 0;
  for (i = 0; i < pitchSize; i++)
    if (pitch[i] != 0)
      break;
  d = i;
  while (i < pitchSize)
  {
    for (from = i++; i < pitchSize; i++)
      if (pitch[i] == 0)
        break;
    for (++i; i < pitchSize; i++)
      if (pitch[i] != 0)
        break;

    midi[midiSize] = pitch[from];
    midi[midiSize + 1] = i - from + d;
    d = 0;
    midiSize += 2;
  }

  return midiSize;
}

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