Pitch PitchDetector::process(float *input, unsigned int numberOfSamples)
{
assert(this->numberOfSamples==numberOfSamples);
int n = numberOfSamples;
float *originalReal = this->FFTBuffer;
// 1.1.时域上加窗
vDSP_vmul(input, 1, this->windowFunc, 1, originalReal, 1, n);
// 分前后加窗没什么不一样啊
// vDSP_vmul(input, 1, this->windowFunc, 1, originalReal+(n/2), 1, n/2);
// vDSP_vmul(input+(n/2), 1, this->windowFunc+(n/2), 1, originalReal, 1, n/2);
// 2.拆成复数形似{1+2i, 3+4i, ..., 1023+1024i} 原始数组可以认为是（COMPLEX*）交错存储 现在拆成COMPLEX_SPLIT非交错（分轨式）存储
vDSP_ctoz((COMPLEX*)originalReal, 2, &this->A, 1, n/2); // 读取originalReal以2的步长塞进A里面
// // 3.fft变换的预设
float originalRealInLog2 = log2f(n);
// FFTSetup setupReal = vDSP_create_fftsetup(originalRealInLog2, FFT_RADIX2);
// 4.傅里叶变换
vDSP_fft_zrip(this->setupReal, &this->A, 1, originalRealInLog2, FFT_FORWARD);
// 5.转换成能量值
vDSP_zvabs(&this->A, 1, this->magnitudes, 1, n/2);
Float32 one = 1;
vDSP_vdbcon(this->magnitudes, 1, &one, this->magnitudes, 1, n/2, 0);
// 6.获取基频f0
float maxValue;
vDSP_Length index;
vDSP_maxvi(this->magnitudes, 1, &maxValue, &index, n/2);
// 6.1.微调参数
double alpha = this->magnitudes[index - 1];
double beta = this->magnitudes[index];
double gamma = this->magnitudes[index + 1];
double p = 0.5 * (alpha - gamma) / (alpha - 2 * beta + gamma);
// 7.转换为频率 indexHZ = index * (SampleRate / (n/2))
float indexHZ = (index+p) * ((this->sampleRate*1.0) / n);
// 8.乐理信息生成
Pitch pitch;
pitch.frequency = indexHZ;
pitch.amplitude = beta;
pitch.key = 12 * log2(indexHZ / 127.09) + 28.5;
pitch.octave = (pitch.key - 3.0) / 12 + 1;
calStep(&pitch);
pitch.stepString = calStep(indexHZ);
return pitch;
}
Error_t
VectorMaxVI(float* value, unsigned* index, const float* src, unsigned length)
{
#ifdef __APPLE__
// Use the Accelerate framework if we have it
vDSP_maxvi(src, 1, value, (unsigned long*)index, length);
#else
float res = FLT_MIN;
for (unsigned i = 0; i < length; ++i)
{
if (src[i] > res)
{
*value = res = src[i];
*index = i;
}
}
#endif
return NOERR;
}
uint_t
fvec_max_elem (fvec_t * s)
{
#ifndef HAVE_ACCELERATE
uint_t j, pos = 0;
smpl_t tmp = 0.0;
for (j = 0; j < s->length; j++) {
pos = (tmp > s->data[j]) ? pos : j;
tmp = (tmp > s->data[j]) ? tmp : s->data[j];
}
#else
smpl_t tmp = 0.;
uint_t pos = 0.;
#if !HAVE_AUBIO_DOUBLE
vDSP_maxvi(s->data, 1, &tmp, (vDSP_Length *)&pos, s->length);
#else
vDSP_maxviD(s->data, 1, &tmp, (vDSP_Length *)&pos, s->length);
#endif
#endif
return pos;
}
