ladspa-pitchshift/formantshifter.cpp
2023-10-30 06:52:43 +06:00

147 lines
4.3 KiB
C++

#include "formantshifter.h"
#include "common.h"
#include "effect.h"
#include "interpolation.h"
#include "loudness.h"
#include "mengumath.h"
#include <algorithm>
#include <array>
#include <cmath>
#include <complex>
#include <cstdint>
using namespace Mengu;
using namespace dsp;
LPCFormantShifter::LPCFormantShifter() {
_transformed_buffer.resize(OverlapSize);
}
Effect::InputDomain LPCFormantShifter::get_input_domain() {
return InputDomain::Time;
};
// push new value of signal
void LPCFormantShifter::push_signal(const Complex *input, const uint32_t &size) {
_raw_buffer.extend_back(input, size);
}
// Last value of transformed signal
uint32_t LPCFormantShifter::pop_transformed_signal(Complex *output, const uint32_t &size) {
std::array<Complex, ProcSize> freq_shifted {0};
std::array<Complex, ProcSize> samples {0};
std::array<Complex, ProcSize> shifted_samples {0};
while (_raw_buffer.size() >= ProcSize && _transformed_buffer.size() < size + OverlapSize) {
// Load sample segment. 0 unused frames
_raw_buffer.to_array(samples.data(), ProcSize);
// do the shifty
_lpc.load_sample(samples.data());
_shift_by_env(
_lpc.get_freq_spectrum().data(),
freq_shifted.data(),
_lpc.get_envelope().data(),
_shift_factor
);
_lpc.get_fft().inverse_transform(freq_shifted.data(), shifted_samples.data());
// Make downward shifts not quieter and upward shifts not louder
// Automatically adjusts for the fact that only half of the frequency spectrum is used
_loudness_norm.normalize(shifted_samples.data(), samples.data(), shifted_samples.data());
// copy to output
mix_and_extend(_transformed_buffer, shifted_samples, OverlapSize, hamming_window);
_raw_buffer.pop_front_many(nullptr, HopSize);
}
if (_transformed_buffer.size() < size + OverlapSize) {
// Not enough samples to output anything
return 0;
}
else {
return _transformed_buffer.pop_front_many(output, size);
}
}
// number of samples that can be output given the current pushed signals of the Effect
uint32_t LPCFormantShifter::n_transformed_ready() const {
return _raw_buffer.size();
};
// resets state of effect to make it reading to take in a new sample
void LPCFormantShifter::reset() {
_raw_sample_filter.reset();
_shifted_sample_filter.reset();
}
// The properties that this Effect exposes to be changed by GUI.
// The index that they are put in is considered the props id
std::vector<EffectPropDesc> LPCFormantShifter::get_property_descs() const {
return {
EffectPropDesc {
.type = EffectPropType::Slider,
.name = "Formant Shift",
.desc = "Scales the formant of pushed signals by this amount",
.slider_data = {
.min_value = 0.5,
.max_value = 2,
.scale = Exp,
}
}
};
}
// Sets a property with the specified id the value declared in the payload
void LPCFormantShifter::set_property(uint32_t id, EffectPropPayload data) {
switch (id) {
case 0:
if (data.type == Slider) {
_shift_factor = data.value;
}
break;
default:
break;
}
}
// Gets the value of a property with the specified id
EffectPropPayload LPCFormantShifter::get_property(uint32_t id) const {
return EffectPropPayload {
.type = Slider,
.value = _shift_factor,
};
};
// rescale an array in the freqency domain by the shape of an envelope if it were to be shifted up or down
void LPCFormantShifter::_shift_by_env(const Complex *input,
Complex *output,
const float *envelope,
const float shift_factor) {
for (uint32_t i = 0; i < ProcSize / 2; i++) {
uint32_t shifted_ind = i / shift_factor;
if (shifted_ind < ProcSize / 2) {
float correction = envelope[shifted_ind] / envelope[i];
if (!std::isfinite(correction)) {
output[i] = Complex(0.0f);
}
else {
output[i] = correction * input[i];
}
}
else {
// output[i] = input[size - 1];
output[i] = Complex(0.0f);
}
}
}