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/***************************************************************************
PitchShiftFilter.cpp - filter for modifying the "pitch_shift"
-------------------
begin : Wed Nov 28 2007
copyright : (C) 2007 by Thomas Eschenbacher
email : Thomas.Eschenbacher@gmx.de
based on synth_pitch_shift_impl.cc from the aRts project
copyright (C) 2000 Jeff Tranter <tranter@pobox.com>
(C) 1999 Stefan Westerfeld <stefan@space.twc.de>
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#include "config.h"
#include <math.h>
#include "libkwave/Sample.h"
#include "libkwave/Utils.h"
#include "PitchShiftFilter.h"
//***************************************************************************
Kwave::PitchShiftFilter::PitchShiftFilter()
:Kwave::SampleSource(nullptr), m_buffer(blockSize()),
m_speed(1.0), m_frequency(0.5), m_dbuffer(),
m_lfopos(0), m_b1pos(0), m_b2pos(0), m_b1inc(0), m_b2inc(0),
m_b1reset(false), m_b2reset(false), m_dbpos(0)
{
initFilter();
}
//***************************************************************************
Kwave::PitchShiftFilter::~PitchShiftFilter()
{
}
//***************************************************************************
void Kwave::PitchShiftFilter::goOn()
{
emit output(m_buffer);
}
//***************************************************************************
void Kwave::PitchShiftFilter::initFilter()
{
m_dbuffer.resize(MAXDELAY);
for (m_dbpos = 0; m_dbpos < MAXDELAY; m_dbpos++)
m_dbuffer[m_dbpos] = 0;
m_dbpos = 0;
m_lfopos = 0;
if (m_speed <= float(1.0)) {
m_b1pos = m_b2pos = 0.0;
m_b1inc = m_b2inc = 1.0f - m_speed;
} else {
/* not yet sure what would be a nice initialization here? */
m_b1pos = m_b2pos = 0.0;
m_b1inc = m_b2inc = 0.0;
}
}
//***************************************************************************
void Kwave::PitchShiftFilter::input(Kwave::SampleArray data)
{
const Kwave::SampleArray &in = data;
Q_ASSERT(Kwave::toInt(in.size()) <= m_dbuffer.size());
bool ok = m_buffer.resize(in.size());
Q_ASSERT(ok);
Q_UNUSED(ok)
const float pi2 = 2 * float(M_PI);
const float lfoposinc = static_cast<float>(m_frequency);
for (unsigned int pos = 0; pos < m_buffer.size(); pos++) {
/*
* fill delay buffer with the input signal
*/
m_dbuffer[m_dbpos] = sample2float(in[pos]);
m_lfopos += lfoposinc;
m_lfopos -= floorf(m_lfopos);
if (m_lfopos < float(0.25)) {
m_b1reset = m_b2reset = false;
}
/*
* _speed < 1.0 (downpitching)
*
* start with current sample and increase delay slowly
*
* _speed > 1.0 (uppitching)
*
* start with a sample from long ago and slowly decrease delay
*/
if (!m_b1reset && m_lfopos > float(0.25)) {
if (m_speed <= float(1.0)) {
m_b1pos = 0;
m_b1inc = 1.0f - m_speed;
} else {
m_b1inc = 1.0f - m_speed;
m_b1pos = 10.0f + ((- m_b1inc) * (1.0f / lfoposinc));
/* 10+ are not strictly necessary */
}
m_b1reset = true;
}
if (!m_b2reset && (m_lfopos > 0.75f)) {
if (m_speed <= float(1.0)) {
m_b2pos = 0;
m_b2inc = 1.0f - m_speed;
} else{
m_b2inc = 1.0f - m_speed;
m_b2pos = 10.0f + ((-m_b2inc) * (1.0f / lfoposinc));
/* 10+ are not strictly necessary */
}
m_b2reset = true;
}
m_b1pos += m_b1inc;
m_b2pos += m_b2inc;
int position, position1;
float error, int_pos;
/*
* Interpolate value from buffer position 1
*/
error = modff(m_b1pos, &int_pos);
position = m_dbpos - Kwave::toInt(int_pos);
if (position < 0)
position += MAXDELAY;
position1 = position - 1;
if (position1 < 0)
position1 += MAXDELAY;
const float b1value = m_dbuffer[position] * (1 - error) +
m_dbuffer[position1] * error;
/*
* Interpolate value from buffer position 2
*/
error = modff(m_b2pos,&int_pos);
position = m_dbpos - Kwave::toInt(int_pos);
if (position < 0)
position += MAXDELAY;
position1 = position-1;
if ( position1 < 0)
position1 += MAXDELAY;
const float b2value = m_dbuffer[position] * (1 - error) +
m_dbuffer[position1] * error;
/*
* Calculate output signal from these two buffers
*/
const float lfo = (sinf(pi2 * m_lfopos) + 1.0f) / 2.0f;
/* position sin lfo variable
*------------------------------------------------------------------
* lfo value: 0.25 1 1 => buffer 2 is used
* 0.75 -1 0 => buffer 1 is used
*/
m_buffer[pos] = float2sample(b1value * (1.0f - lfo) + b2value * lfo);
/*
* increment delay buffer position
*/
m_dbpos++;
if (m_dbpos == MAXDELAY)
m_dbpos = 0;
}
}
//***************************************************************************
void Kwave::PitchShiftFilter::setSpeed(const QVariant speed)
{
float new_speed = QVariant(speed).toFloat();
if (qFuzzyCompare(new_speed, m_speed)) return; // nothing to do
m_speed = new_speed;
initFilter();
}
//***************************************************************************
void Kwave::PitchShiftFilter::setFrequency(const QVariant freq)
{
float new_freq = QVariant(freq).toFloat();
if (qFuzzyCompare(new_freq, m_frequency)) return; // nothing to do
m_frequency = new_freq;
initFilter();
}
//***************************************************************************
//***************************************************************************
#include "moc_PitchShiftFilter.cpp"
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