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Fix/pitch shift #166

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Fix/pitch shift #166

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90978ea
changed clamping of phasor to allow negative frequency
Oct 1, 2021
6bcc406
simplified pitch shifter, and fixed issues with negative tranposition.
Oct 1, 2021
56525c3
changed quantize default to false, and added documentation for init.
Oct 1, 2021
8fa08b1
fixed the 'fun' param to work the same when transposing below 0, and …
Oct 11, 2021
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2 changes: 1 addition & 1 deletion Source/Control/phasor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ float Phasor::Process()
}
if(phs_ < 0.0f)
{
phs_ = 0.0f;
phs_ += TWOPI_F;
}
return out;
}
113 changes: 47 additions & 66 deletions Source/Effects/pitchshifter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,13 +10,6 @@
#include "Utility/delayline.h"
#include "Control/phasor.h"

/** Shift can be 30-100 ms lets just start with 50 for now.
0.050 * SR = 2400 samples (at 48kHz)
*/
#define SHIFT_BUFFER_SIZE 16384
//#define SHIFT_BUFFER_SIZE 4800
//#define SHIFT_BUFFER_SIZE 8192
//#define SHIFT_BUFFER_SIZE 1024

namespace daisysp
{
Expand Down Expand Up @@ -49,7 +42,7 @@ t = 1 - ((s *f) / R)
r is the sample_rate

solving for t = 12.0
f = (12 - 1) * 48000 / SHIFT_BUFFER_SIZE;
f = (12 - 1) * 48000 / kShiftDelaySize;

\todo - move hash_xs32 and myrand to dsp.h and give appropriate names
*/
Expand All @@ -58,42 +51,55 @@ class PitchShifter
public:
PitchShifter() {}
~PitchShifter() {}
/** Initialize pitch shifter


/** Initialize pitch shifter
* \param sr the expected samplerate in Hz of the audio engines
* \param quantize_semitones locks transpositions to integer values (defaults to false)
*/
void Init(float sr)
void Init(float sr, bool quantize_semitones = false)
{
force_recalc_ = false;
sr_ = sr;
mod_freq_ = 5.0f;
SetSemitones();
for(uint8_t i = 0; i < 2; i++)
{
gain_[i] = 0.0f;
d_[i].Init();
phs_[i].Init(sr, 50, i == 0 ? 0 : PI_F);
}
shift_up_ = true;
del_size_ = SHIFT_BUFFER_SIZE;
del_size_ = kShiftDelaySize;
SetDelSize(del_size_);
fun_ = 0.0f;
fun_ = 0.0f;
quantize_semitones_ = quantize_semitones;
}

/** process pitch shifter
*/
float Process(float &in)
float Process(float in)
{
float val, fade1, fade2;
// First Process delay mod/crossfade
fade1 = phs_[0].Process();
fade2 = phs_[1].Process();
if(prev_phs_a_ > fade1)
fade1 = phs_[0].Process();
fade2 = phs_[1].Process();
bool recalc_a_fun = ((transpose_ >= 0.f) && (prev_phs_a_ > fade1))
|| ((transpose_ < 0.f) && prev_phs_a_ < fade1);
bool recalc_b_fun = ((transpose_ >= 0.f) && (prev_phs_b_ > fade2))
|| ((transpose_ < 0.f) && prev_phs_b_ < fade2);
// Randomly trigger mod recalc when tranpose is 0 so that the "fun"
// parameter still does something when not transposing
bool rand_retrig = (transpose_ >= -0.25f && transpose_ < 0.25f);
if(rand_retrig && fun_ > 0.f)
if(myrand() % 65536 < 4)
recalc_a_fun = recalc_b_fun = true;
if(recalc_a_fun)
{
mod_a_amt_ = fun_ * ((float)(myrand() % 255) / 255.0f)
* (del_size_ * 0.5f);
mod_coeff_[0]
= 0.0002f + (((float)(myrand() % 255) / 255.0f) * 0.001f);
}
if(prev_phs_b_ > fade2)
if(recalc_b_fun)
{
mod_b_amt_ = fun_ * ((float)(myrand() % 255) / 255.0f)
* (del_size_ * 0.5f);
Expand All @@ -104,13 +110,10 @@ class PitchShifter
slewed_mod_[1] += mod_coeff_[1] * (mod_b_amt_ - slewed_mod_[1]);
prev_phs_a_ = fade1;
prev_phs_b_ = fade2;
if(shift_up_)
{
fade1 = 1.0f - fade1;
fade2 = 1.0f - fade2;
}
mod_[0] = fade1 * (del_size_ - 1);
mod_[1] = fade2 * (del_size_ - 1);
fade1 = 1.0f - fade1;
fade2 = 1.0f - fade2;
mod_[0] = fade1 * (del_size_ - 1);
mod_[1] = fade2 * (del_size_ - 1);
#ifdef USE_ARM_DSP
gain_[0] = arm_sin_f32(fade1 * (float)M_PI);
gain_[1] = arm_sin_f32(fade2 * (float)M_PI);
Expand All @@ -123,9 +126,8 @@ class PitchShifter
d_[0].Write(in);
d_[1].Write(in);
// Modulate Delay Lines
//mod_a_amt = mod_b_amt = 0.0f;
d_[0].SetDelay(mod_[0] + mod_a_amt_);
d_[1].SetDelay(mod_[1] + mod_b_amt_);
// d_[0].SetDelay(mod_[0] + mod_a_amt_);
// d_[1].SetDelay(mod_[1] + mod_b_amt_);
d_[0].SetDelay(mod_[0] + slewed_mod_[0]);
d_[1].SetDelay(mod_[1] + slewed_mod_[1]);
val = 0.0f;
Expand All @@ -138,27 +140,12 @@ class PitchShifter
*/
void SetTransposition(const float &transpose)
{
float ratio;
uint8_t idx;
float ratio;
if(transpose_ != transpose || force_recalc_)
{
transpose_ = transpose;
idx = (uint8_t)fabsf(transpose);
ratio = semitone_ratios_[idx % 12];
ratio *= (uint8_t)(fabsf(transpose) / 12) + 1;
if(transpose > 0.0f)
{
shift_up_ = true;
}
else
{
shift_up_ = false;
}
mod_freq_ = ((ratio - 1.0f) * sr_) / del_size_;
if(mod_freq_ < 0.0f)
{
mod_freq_ = 0.0f;
}
transpose_ = quantize_semitones_ ? (int32_t)transpose : transpose;
ratio = pow(2.f, transpose_ / 12.f);
mod_freq_ = ((ratio - 1.0f) * sr_) / del_size_;
phs_[0].SetFreq(mod_freq_);
phs_[1].SetFreq(mod_freq_);
if(force_recalc_)
Expand All @@ -172,7 +159,7 @@ class PitchShifter
*/
void SetDelSize(uint32_t size)
{
del_size_ = size < SHIFT_BUFFER_SIZE ? size : SHIFT_BUFFER_SIZE;
del_size_ = size < kShiftDelaySize ? size : kShiftDelaySize;
force_recalc_ = true;
SetTransposition(transpose_);
}
Expand All @@ -182,29 +169,23 @@ class PitchShifter
inline void SetFun(float f) { fun_ = f; }

private:
inline void SetSemitones()
{
for(size_t i = 0; i < 12; i++)
{
semitone_ratios_[i] = powf(2.0f, (float)i / 12);
}
}
typedef DelayLine<float, SHIFT_BUFFER_SIZE> ShiftDelay;
ShiftDelay d_[2];
float pitch_shift_, mod_freq_;
uint32_t del_size_;
/** lfo stuff
*/
/** Shift can be 30-100 ms lets just start with 50 for now.
0.050 * SR = 2400 samples (at 48kHz) */
static constexpr size_t kShiftDelaySize = 16384;
typedef DelayLine<float, kShiftDelaySize> ShiftDelay;
ShiftDelay d_[2];
float pitch_shift_, mod_freq_;
uint32_t del_size_;
/** lfo stuff */
bool force_recalc_;
float sr_;
bool shift_up_;
Phasor phs_[2];
float gain_[2], mod_[2], transpose_;
float fun_, mod_a_amt_, mod_b_amt_, prev_phs_a_, prev_phs_b_;
float slewed_mod_[2], mod_coeff_[2];
/** pitch stuff
*/
float semitone_ratios_[12];

/** Config stuff */
bool quantize_semitones_;
};
} // namespace daisysp

Expand Down