staffpad::anonymous_namespace{TimeAndPitch.cpp} Namespace Reference

Functions
float	lagrange6 (const float(&smp)[6], float t)
void	generateRandomPhaseVector (float *dst, size_t size, std::mt19937 &gen)
float	_unwrapPhase (float arg)
void	_unwrapPhaseVec (float *v, int n)
void	_fft_shift (float *v, int n)
	rotate even-sized array by half its size to align fft phase at the center More...
void	_lr_to_ms (float *ch1, float *ch2, int n)
void	_ms_to_lr (float *ch1, float *ch2, int n)

Variables
constexpr double	twoPi = 6.28318530717958647692f

Function Documentation

_fft_shift()

void staffpad::anonymous_namespace{TimeAndPitch.cpp}::_fft_shift	(	float *	v,
		int	n
	)

rotate even-sized array by half its size to align fft phase at the center

Definition at line 205 of file TimeAndPitch.cpp.

{
  assert((n & 1) == 0);
  int n2 = n >> 1;
  audio::simd::perform_parallel_simd_aligned(v, v + n2, n2, [](auto& a, auto& b) {
    auto tmp = a;
    a = b;
    b = tmp;
  });
}

References staffpad::audio::simd::perform_parallel_simd_aligned().

Referenced by staffpad::TimeAndPitch::_process_hop().

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_lr_to_ms()

void staffpad::anonymous_namespace{TimeAndPitch.cpp}::_lr_to_ms	(	float *	ch1,
		float *	ch2,
		int	n
	)

Definition at line 216 of file TimeAndPitch.cpp.

{
  audio::simd::perform_parallel_simd_aligned(ch1, ch2, n, [](auto& a, auto& b) {
    auto l = a, r = b;
    a = 0.5f * (l + r);
    b = 0.5f * (l - r);
  });
}

References staffpad::audio::simd::perform_parallel_simd_aligned().

Referenced by staffpad::TimeAndPitch::_process_hop().

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_ms_to_lr()

void staffpad::anonymous_namespace{TimeAndPitch.cpp}::_ms_to_lr	(	float *	ch1,
		float *	ch2,
		int	n
	)

Definition at line 225 of file TimeAndPitch.cpp.

{
  audio::simd::perform_parallel_simd_aligned(ch1, ch2, n, [](auto& a, auto& b) {
    auto m = a, s = b;
    a = m + s;
    b = m - s;
  });
}

References staffpad::audio::simd::perform_parallel_simd_aligned().

Referenced by staffpad::TimeAndPitch::_process_hop().

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_unwrapPhase()

float staffpad::anonymous_namespace{TimeAndPitch.cpp}::_unwrapPhase ( float  arg )

inline

Definition at line 193 of file TimeAndPitch.cpp.

{
  using namespace audio::simd;
  return arg - rint(arg * 0.15915494309f) * 6.283185307f;
}

References staffpad::audio::simd::rint().

Referenced by staffpad::TimeAndPitch::_time_stretch().

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_unwrapPhaseVec()

void staffpad::anonymous_namespace{TimeAndPitch.cpp}::_unwrapPhaseVec	(	float *	v,
		int	n
	)

Definition at line 199 of file TimeAndPitch.cpp.

{
  audio::simd::perform_parallel_simd_aligned(v, n, [](auto& a) { a = a - rint(a * 0.15915494309f) * 6.283185307f; });
}

References staffpad::audio::simd::perform_parallel_simd_aligned(), and staffpad::audio::simd::rint().

Referenced by staffpad::TimeAndPitch::_process_hop().

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generateRandomPhaseVector()

void staffpad::anonymous_namespace{TimeAndPitch.cpp}::generateRandomPhaseVector	(	float *	dst,
		size_t	size,
		std::mt19937 &	gen
	)

Definition at line 48 of file TimeAndPitch.cpp.

{
   std::vector<std::complex<float>> v(size);
   std::uniform_real_distribution<float> dis(
      -3.14159265358979323846f, 3.14159265358979323846f);
   std::for_each(dst, dst + size, [&dis, &gen](auto& a) { a = dis(gen); });
}

References size.

Referenced by staffpad::TimeAndPitch::setup().

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lagrange6()

float staffpad::anonymous_namespace{TimeAndPitch.cpp}::lagrange6 ( const float(&)  smp[6], float  t  )

inline

6-point lagrange interpolator SNR ~ -35.2db interpolates between samples 2 and 3 using t.

smp pointer to a memory region containing 6 samples t fractional sample to interpolate t >= 0 && t < 1 return value the interpolated sample

Definition at line 30 of file TimeAndPitch.cpp.

{
  auto* y = &smp[2];
 
  auto ym1_y1 = y[-1] + y[1];
  auto twentyfourth_ym2_y2 = 1.f / 24.f * (y[-2] + y[2]);
  auto c0 = y[0];
  auto c1 = 0.05f * y[-2] - 0.5f * y[-1] - 1.f / 3.f * y[0] + y[1] - 0.25f * y[2] + 1.f / 30.f * y[3];
  auto c2 = 2.f / 3.f * ym1_y1 - 1.25f * y[0] - twentyfourth_ym2_y2;
  auto c3 = 5.f / 12.f * y[0] - 7.f / 12.f * y[1] + 7.f / 24.f * y[2] - 1.f / 24.f * (y[-2] + y[-1] + y[3]);
  auto c4 = 0.25f * y[0] - 1.f / 6.f * ym1_y1 + twentyfourth_ym2_y2;
  auto c5 = 1.f / 120.f * (y[3] - y[-2]) + 1.f / 24.f * (y[-1] - y[2]) + 1.f / 12.f * (y[1] - y[0]);
 
  // Estrin's scheme
  auto t2 = t * t;
  return (c0 + c1 * t) + (c2 + c3 * t) * t2 + (c4 + c5 * t) * t2 * t2;
}

Referenced by staffpad::TimeAndPitch::feedAudio().

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Variable Documentation

twoPi

constexpr double staffpad::anonymous_namespace{TimeAndPitch.cpp}::twoPi = 6.28318530717958647692f

constexpr

Definition at line 20 of file TimeAndPitch.cpp.

Referenced by staffpad::TimeAndPitch::setup().