Kwave::PitchShiftFilter Class Reference

#include <PitchShiftFilter.h>

Inheritance diagram for Kwave::PitchShiftFilter:

Collaboration diagram for Kwave::PitchShiftFilter:

Public Slots
void	input (Kwave::SampleArray data)
void	setSpeed (const QVariant speed)
void	setFrequency (const QVariant freq)

Signals
void	output (Kwave::SampleArray data)
Signals inherited from Kwave::StreamObject
void	attributeChanged (const QVariant value)

Public Member Functions
	PitchShiftFilter ()
virtual	~PitchShiftFilter () Q_DECL_OVERRIDE
virtual void	goOn () Q_DECL_OVERRIDE
Public Member Functions inherited from Kwave::SampleSource
	SampleSource (QObject *parent=Q_NULLPTR)
virtual	~SampleSource ()
virtual bool	done () const
Public Member Functions inherited from Kwave::StreamObject
	StreamObject (QObject *parent=Q_NULLPTR)
virtual	~StreamObject ()
virtual unsigned int	tracks () const
virtual Kwave::StreamObject *	operator[] (unsigned int track)
virtual unsigned int	tracksOfPort (const char *port) const
virtual Kwave::StreamObject *	port (const char *port, unsigned int track)
virtual unsigned int	blockSize () const
void	setAttribute (const char *attribute, const QVariant &value)

Private Types
enum	{ MAXDELAY = 1000000 }

Private Member Functions
void	initFilter ()

Private Attributes
Kwave::SampleArray	m_buffer
float	m_speed
float	m_frequency
QVector< float >	m_dbuffer
float	m_lfopos
float	m_b1pos
float	m_b2pos
float	m_b1inc
float	m_b2inc
bool	m_b1reset
bool	m_b2reset
int	m_dbpos

Additional Inherited Members
Static Public Member Functions inherited from Kwave::StreamObject
static void	setInteractive (bool interactive)

Detailed Description

Definition at line 38 of file PitchShiftFilter.h.

Member Enumeration Documentation

anonymous enum

anonymous enum

private

Enumerator
MAXDELAY

Definition at line 90 of file PitchShiftFilter.h.

{ MAXDELAY = 1000000 };

Constructor & Destructor Documentation

PitchShiftFilter()

Kwave::PitchShiftFilter::PitchShiftFilter

(

)

Constructor

Definition at line 34 of file PitchShiftFilter.cpp.

References initFilter().

    :Kwave::SampleSource(Q_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();
}

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~PitchShiftFilter()

Kwave::PitchShiftFilter::~PitchShiftFilter ( )

virtual

Destructor

Definition at line 44 of file PitchShiftFilter.cpp.

{
}

Member Function Documentation

goOn()

void Kwave::PitchShiftFilter::goOn ( )

virtual

does the calculation

Implements Kwave::SampleSource.

Definition at line 49 of file PitchShiftFilter.cpp.

References m_buffer, and output().

{
    emit output(m_buffer);
}

initFilter()

void Kwave::PitchShiftFilter::initFilter ( )

private

reset/initialize the filter and buffer

Definition at line 55 of file PitchShiftFilter.cpp.

References m_b1inc, m_b1pos, m_b2inc, m_b2pos, m_dbpos, m_dbuffer, m_lfopos, m_speed, and MAXDELAY.

Referenced by PitchShiftFilter(), setFrequency(), and setSpeed().

{
    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;
    }
}

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input

void Kwave::PitchShiftFilter::input ( Kwave::SampleArray  data )

slot

receives input data

Definition at line 75 of file PitchShiftFilter.cpp.

References float2sample(), m_b1inc, m_b1pos, m_b1reset, m_b2inc, m_b2pos, m_b2reset, m_buffer, m_dbpos, m_dbuffer, m_frequency, m_lfopos, m_speed, MAXDELAY, Kwave::SampleArray::resize(), sample2float(), Kwave::SampleArray::size(), and Kwave::toInt().

{
    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;
    }

}

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output

void Kwave::PitchShiftFilter::output ( Kwave::SampleArray  data )

signal

emits a block with the filtered data

Referenced by goOn().

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setFrequency

void Kwave::PitchShiftFilter::setFrequency ( const QVariant  freq )

slot

Sets the frequency parameter

Parameters

freq	the normed frequency

Definition at line 204 of file PitchShiftFilter.cpp.

References initFilter(), and m_frequency.

{
    float new_freq = QVariant(freq).toFloat();
    if (qFuzzyCompare(new_freq, m_frequency)) return; // nothing to do

    m_frequency = new_freq;
    initFilter();
}

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setSpeed

void Kwave::PitchShiftFilter::setSpeed ( const QVariant  speed )

slot

Sets the speed factor

Parameters

speed

factor as a double

Definition at line 194 of file PitchShiftFilter.cpp.

References initFilter(), and m_speed.

{
    float new_speed = QVariant(speed).toFloat();
    if (qFuzzyCompare(new_speed, m_speed)) return; // nothing to do

    m_speed = new_speed;
    initFilter();
}

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Member Data Documentation

m_b1inc

float Kwave::PitchShiftFilter::m_b1inc

private

Definition at line 96 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_b1pos

float Kwave::PitchShiftFilter::m_b1pos

private

Definition at line 94 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_b1reset

bool Kwave::PitchShiftFilter::m_b1reset

private

Definition at line 98 of file PitchShiftFilter.h.

Referenced by input().

m_b2inc

float Kwave::PitchShiftFilter::m_b2inc

private

Definition at line 97 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_b2pos

float Kwave::PitchShiftFilter::m_b2pos

private

Definition at line 95 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_b2reset

bool Kwave::PitchShiftFilter::m_b2reset

private

Definition at line 99 of file PitchShiftFilter.h.

Referenced by input().

m_buffer

Kwave::SampleArray Kwave::PitchShiftFilter::m_buffer

private

buffer for input

Definition at line 82 of file PitchShiftFilter.h.

Referenced by goOn(), and input().

m_dbpos

int Kwave::PitchShiftFilter::m_dbpos

private

Definition at line 100 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_dbuffer

QVector<float> Kwave::PitchShiftFilter::m_dbuffer

private

Definition at line 92 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_frequency

float Kwave::PitchShiftFilter::m_frequency

private

base frequency

Definition at line 88 of file PitchShiftFilter.h.

Referenced by input(), and setFrequency().

m_lfopos

float Kwave::PitchShiftFilter::m_lfopos

private

Definition at line 93 of file PitchShiftFilter.h.

Referenced by initFilter(), and input().

m_speed

float Kwave::PitchShiftFilter::m_speed

private

speed factor

Definition at line 85 of file PitchShiftFilter.h.

Referenced by initFilter(), input(), and setSpeed().

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The documentation for this class was generated from the following files:

• plugins/pitch_shift/PitchShiftFilter.h
• plugins/pitch_shift/PitchShiftFilter.cpp