Nsound::FilterFlanger Class Reference

A class for filtering audio in the frequecy domain. More...

#include <Nsound/FilterFlanger.h>

Inheritance diagram for Nsound::FilterFlanger:

Public Member Functions
	FilterFlanger (const float64 &sample_rate, const float64 &frequency, const float64 &max_delay_time_seconds)
	FilterFlanger (const FilterFlanger &copy)
	~FilterFlanger ()
AudioStream	filter (const AudioStream &x)
AudioStream	filter (const AudioStream &x, const float64 &frequency)
AudioStream	filter (const AudioStream &x, const float64 &frequency, const float64 &delay)
AudioStream	filter (const AudioStream &x, const Buffer &frequency, const Buffer &delay)
Buffer	filter (const Buffer &x)
Buffer	filter (const Buffer &x, const float64 &frequency)
Buffer	filter (const Buffer &x, const float64 &frequency, const float64 &delay)
Buffer	filter (const Buffer &x, const Buffer &frequency, const Buffer &delay)
float64	filter (const float64 &x)
float64	filter (const float64 &x, const float64 &frequency)
float64	filter (const float64 &x, const float64 &frequency, const float64 &delay)
FilterFlanger &	operator= (const FilterFlanger &rhs)
void	plot (boolean show_fc=false, boolean show_phase=false)
void	reset ()
void	setRealtime (bool flag)
AudioStream	filter (const AudioStream &x, const Buffer &frequencies)
Buffer	filter (const Buffer &x, const Buffer &frequencies)
Buffer	getFrequencyAxis (const uint32 n_fft=8192)
Buffer	getFrequencyResponse (const uint32 n_fft=8192)
Buffer	getImpulseResponse (const uint32 n_samples=8192)
virtual uint32	getKernelSize () const
Buffer	getPhaseResponse ()
float64	getSampleRate () const
void	plot (boolean show_phase=false)

Protected Attributes
float64	frequency_
float64	max_delay_
FilterDelay *	delay_
Generator *	gen_
float64	sample_rate_
float64	two_pi_over_sample_rate_
float64	sample_time_
uint32	kernel_size_
bool	is_realtime_

Detailed Description

A class for filtering audio in the frequecy domain.

Definition at line 49 of file FilterFlanger.h.

Constructor & Destructor Documentation

FilterFlanger::FilterFlanger	(	const float64 &	sample_rate,
		const float64 &	frequency,
		const float64 &	max_delay_time_seconds
	)

Definition at line 51 of file FilterFlanger.cc.

References delay_, frequency_, gen_, Nsound::Generator::generate(), M_ASSERT_VALUE, max_delay_, and Nsound::Filter::sample_rate_.

    :
    Filter(sample_rate),
    frequency_(frequency),
    max_delay_(max_delay_time_seconds),
    delay_(NULL),
    gen_(NULL)
{
    M_ASSERT_VALUE(frequency_, >, 0.0);
    M_ASSERT_VALUE(max_delay_, >, 0.0);

    delay_ = new FilterDelay(sample_rate_, max_delay_);

    Sine sin(sample_rate_);

    Buffer waveform = (1.0 + sin.generate(1.0, 1.0)) / 2.0;

    gen_ = new Generator(sample_rate_, waveform);
}

FilterFlanger::FilterFlanger

(

const FilterFlanger &

copy

)

Definition at line 76 of file FilterFlanger.cc.

References delay_, gen_, Nsound::Generator::generate(), max_delay_, and Nsound::Filter::sample_rate_.

    :
    Filter(copy.sample_rate_),
    frequency_(copy.frequency_),
    max_delay_(copy.max_delay_),
    delay_(NULL),
    gen_(NULL)
{
    delay_ = new FilterDelay(sample_rate_, max_delay_);

    Sine sin(sample_rate_);

    Buffer waveform = (1.0 + sin.generate(1.0, 1.0)) / 2.0;

    gen_ = new Generator(sample_rate_, waveform);

    *this = copy;
}

FilterFlanger::~FilterFlanger

(

)

Definition at line 97 of file FilterFlanger.cc.

References delay_, and gen_.

{
    delete delay_;
    delete gen_;
}

Member Function Documentation

AudioStream FilterFlanger::filter

(

const AudioStream &

x

)

Definition at line 105 of file FilterFlanger.cc.

References Nsound::Filter::filter().

Referenced by filter().

{
    return Filter::filter(x);
}

AudioStream FilterFlanger::filter	(	const AudioStream &	x,
		const float64 &	frequency
	)

Definition at line 112 of file FilterFlanger.cc.

References Nsound::Filter::filter().

{
    return Filter::filter(x, frequency);
}

AudioStream FilterFlanger::filter	(	const AudioStream &	x,
		const float64 &	frequency,
		const float64 &	delay
	)

Definition at line 119 of file FilterFlanger.cc.

References filter(), Nsound::AudioStream::getNChannels(), and Nsound::AudioStream::getSampleRate().

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequency, delay);
    }

    return y;
}

AudioStream FilterFlanger::filter	(	const AudioStream &	x,
		const Buffer &	frequency,
		const Buffer &	delay
	)

Definition at line 138 of file FilterFlanger.cc.

References filter(), Nsound::AudioStream::getNChannels(), and Nsound::AudioStream::getSampleRate().

{
    uint32 n_channels = x.getNChannels();

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequency, delay);
    }

    return y;
}

Buffer FilterFlanger::filter

(

const Buffer &

x

)

Definition at line 157 of file FilterFlanger.cc.

References filter(), frequency_, Nsound::Buffer::getLength(), max_delay_, and reset().

{
    reset();

    Buffer y(x.getLength());

    uint32 x_samples = x.getLength();

    for(uint32 i = 0; i < x_samples; ++i)
    {
        y << filter(x[i], frequency_, max_delay_);
    }

    return y;
}

Buffer FilterFlanger::filter	(	const Buffer &	x,
		const float64 &	frequency
	)

Definition at line 175 of file FilterFlanger.cc.

References filter(), Nsound::Buffer::getLength(), max_delay_, and reset().

{
    reset();

    Buffer y(x.getLength());

    uint32 x_samples = x.getLength();

    for(uint32 i = 0; i < x_samples; ++i)
    {
        y << filter(x[i], frequency, max_delay_);
    }

    return y;
}

Buffer FilterFlanger::filter	(	const Buffer &	x,
		const float64 &	frequency,
		const float64 &	delay
	)

Definition at line 193 of file FilterFlanger.cc.

References filter(), Nsound::Buffer::getLength(), and reset().

{
    reset();

    Buffer y(x.getLength());

    uint32 x_samples = x.getLength();

    for(uint32 i = 0; i < x_samples; ++i)
    {
        y << filter(x[i], frequency, delay);
    }

    return y;
}

Buffer FilterFlanger::filter	(	const Buffer &	x,
		const Buffer &	frequency,
		const Buffer &	delay
	)

Definition at line 211 of file FilterFlanger.cc.

References Nsound::Buffer::cbegin(), filter(), Nsound::Buffer::getLength(), and reset().

{
    reset();

    Buffer y(x.getLength());

    uint32 x_samples = x.getLength();

    Buffer::const_circular_iterator f = frequency.cbegin();
    Buffer::const_circular_iterator d = delay.cbegin();

    for(uint32 i = 0; i < x_samples; ++i)
    {
        y << filter(x[i], *f, *d);
    }

    return y;
}

float64 FilterFlanger::filter ( const float64 &  x )

virtual

Implements Nsound::Filter.

Definition at line 232 of file FilterFlanger.cc.

References filter(), frequency_, and max_delay_.

{
    return filter(x, frequency_, max_delay_);

}

float64 FilterFlanger::filter ( const float64 &  x, const float64 &  frequency  )

virtual

Implements Nsound::Filter.

Definition at line 240 of file FilterFlanger.cc.

References filter(), and max_delay_.

{
    return filter(x, frequency, max_delay_);

}

float64 FilterFlanger::filter	(	const float64 &	x,
		const float64 &	frequency,
		const float64 &	delay
	)

Definition at line 248 of file FilterFlanger.cc.

References delay_, Nsound::FilterDelay::filter(), gen_, and Nsound::Generator::generate().

{
    float64 f = gen_->generate(frequency);

    float64 y = delay_->filter(x, f*delay);

    return (y+x) / 2.0;
}

FilterFlanger & FilterFlanger::operator=

(

const FilterFlanger &

rhs

)

Definition at line 260 of file FilterFlanger.cc.

References delay_, frequency_, gen_, max_delay_, reset(), and Nsound::Filter::sample_rate_.

{
    if(this == &rhs)
    {
        return *this;
    }

    sample_rate_ = rhs.sample_rate_;
    frequency_   = rhs.frequency_;
    max_delay_   = rhs.max_delay_;
    *delay_      = *rhs.delay_;
    *gen_        = *rhs.gen_;

    reset();

    return *this;
}

void FilterFlanger::plot	(	boolean	show_fc = false,
		boolean	show_phase = false
	)

Definition at line 280 of file FilterFlanger.cc.

References frequency_, max_delay_, Nsound::Filter::plot(), Nsound::Filter::sample_rate_, Nsound::Plotter::subplot(), and Nsound::Plotter::title().

{
    char title[128];
    sprintf(title,
        "Flanger Frequency Response\n"
        "sr = %0.1f Hz, f = %0.1f Hz, delay = %0.3f ms",
        sample_rate_,
        frequency_,
        max_delay_ * 1000.0);

    Filter::plot(show_phase);

    Plotter pylab;

    uint32 n_rows = 1;

    if(show_phase)
    {
        n_rows = 2;
    }

    if(show_fc)
    {
        pylab.subplot(n_rows, 1, 1);
    }

    pylab.title(title);
}

void FilterFlanger::reset ( )

virtual

Implements Nsound::Filter.

Definition at line 311 of file FilterFlanger.cc.

References delay_, gen_, Nsound::FilterDelay::reset(), and Nsound::Generator::reset().

Referenced by filter(), and operator=().

{
    delay_->reset();
    gen_->reset();
}

void Nsound::Filter::setRealtime ( bool  flag )

inlineinherited

Definition at line 57 of file Filter.h.

References Nsound::Filter::is_realtime_.

{is_realtime_ = flag;}

AudioStream Filter::filter ( const AudioStream &  x, const Buffer &  frequencies  )

inherited

Definition at line 99 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), Nsound::Filter::is_realtime_, M_THROW, and Nsound::Filter::reset().

{
    if(!is_realtime_) reset();

    uint32 n_channels = x.getNChannels();

    if(is_realtime_ && n_channels > 1)
    {
        M_THROW("In real-time mode, a filter per audio channel must be used!");
    }

    AudioStream y(x.getSampleRate(), n_channels);

    for(uint32 channel = 0; channel < n_channels; ++channel)
    {
        y[channel] = filter(x[channel], frequency);
    }

    return y;
}

Buffer Filter::filter ( const Buffer &  x, const Buffer &  frequencies  )

inherited

Definition at line 161 of file Filter.cc.

References Nsound::Buffer::begin(), Nsound::Buffer::cbegin(), Nsound::Buffer::end(), Nsound::Filter::filter(), Nsound::Buffer::getLength(), Nsound::Filter::is_realtime_, and Nsound::Filter::reset().

{
    if(!is_realtime_) reset();

    Buffer::const_circular_iterator freq = frequencies.cbegin();

    Buffer::const_iterator itor = x.begin();
    Buffer::const_iterator end = x.end();

    Buffer y(x.getLength());

    while(itor != end)
    {
        y << filter(*itor, *freq);

        ++itor;
        ++freq;
    }

    return y;
}

Buffer Filter::getFrequencyAxis ( const uint32  n_fft = 8192 )

inherited

Definition at line 185 of file Filter.cc.

References Nsound::FFTransform::roundUp2(), and Nsound::Filter::sample_rate_.

Referenced by main(), Nsound::Filter::plot(), and Nsound::FilterIIR::savePlot().

{
    uint32 fft_chunk_size = FFTransform::roundUp2(
        static_cast<int32>(n_fft));

    uint32 n_samples = fft_chunk_size / 2 + 1;

    float64 f_step = (1.0 / (static_cast<float64>(fft_chunk_size) / 2.0))
                   * (sample_rate_ / 2.0);

    Buffer f_axis;

    float64 f = 0.0;

    for(uint32 i = 0; i < n_samples; ++i)
    {
        f_axis << f;
        f += f_step;
    }

    return f_axis;
};

Buffer Filter::getFrequencyResponse ( const uint32  n_fft = 8192 )

inherited

Definition at line 210 of file Filter.cc.

References Nsound::FFTransform::fft(), Nsound::Filter::getImpulseResponse(), and Nsound::Filter::sample_rate_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), FilterLeastSquaresFIR_UnitTest(), Nsound::FilterIIR::getRMS(), main(), Nsound::Filter::plot(), and Nsound::FilterIIR::savePlot().

{
    FFTransform fft(sample_rate_);

//~    fft.setWindow(HANNING);

    FFTChunkVector vec;

    vec = fft.fft(getImpulseResponse(), n_fft);

    return vec[0].getMagnitude();
}

Buffer Filter::getImpulseResponse ( const uint32  n_samples = 8192 )

inherited

Definition at line 225 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::Filter::is_realtime_, and Nsound::Filter::reset().

Referenced by Nsound::Filter::getFrequencyResponse(), Nsound::FilterHighPassFIR::getImpulseResponse(), Nsound::FilterLowPassFIR::getImpulseResponse(), Nsound::FilterLeastSquaresFIR::getImpulseResponse(), Nsound::FilterIIR::getImpulseResponse(), and Nsound::Filter::getPhaseResponse().

{
    if(!is_realtime_) reset();

    Buffer response(n_samples);

    response << filter(1.0);

    for(uint32 i = 1; i < n_samples; ++i)
    {
        response << filter(0.0);
    }

    if(!is_realtime_) reset();

    return response;
}

virtual uint32 Nsound::Filter::getKernelSize ( ) const

inlinevirtualinherited

Reimplemented in Nsound::FilterIIR, and Nsound::FilterTone.

Definition at line 96 of file Filter.h.

References Nsound::Filter::kernel_size_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterBandPassIIR::plot(), and Nsound::FilterBandRejectIIR::plot().

{return kernel_size_;};

Buffer Filter::getPhaseResponse ( )

inherited

Definition at line 245 of file Filter.cc.

References Nsound::FFTransform::fft(), Nsound::Filter::getImpulseResponse(), Nsound::Buffer::getLength(), Nsound::Filter::sample_rate_, and Nsound::Buffer::subbuffer().

Referenced by Nsound::Filter::plot().

{
    uint32 n_samples = static_cast<uint32>(sample_rate_ * 2);

    FFTransform fft(n_samples);

    FFTChunkVector vec;

    vec = fft.fft(getImpulseResponse(), n_samples);

    Buffer phase = vec[0].getPhase();

    return phase.subbuffer(0, phase.getLength() / 2 + 1);
}

float64 Nsound::Filter::getSampleRate ( ) const

inlineinherited

Definition at line 102 of file Filter.h.

References Nsound::Filter::sample_rate_.

{ return sample_rate_; };

void Filter::plot ( boolean  show_phase = false )

inherited

Definition at line 262 of file Filter.cc.

References Nsound::Plotter::figure(), Nsound::Buffer::getdB(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Buffer::getMax(), Nsound::Filter::getPhaseResponse(), Nsound::Plotter::plot(), Nsound::Plotter::subplot(), Nsound::Plotter::xlabel(), Nsound::Plotter::ylabel(), and Nsound::Plotter::ylim().

Referenced by main(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassVocoder::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandPassIIR::plot(), and Nsound::FilterParametricEqualizer::plot().

{
    Buffer x = getFrequencyAxis();
    Buffer fr = getFrequencyResponse().getdB();

    Plotter pylab;

    pylab.figure();

    uint32 n_rows = 1;
    uint32 n_cols = 1;

    if(show_phase)
    {
        n_rows = 2;
    }

    pylab.subplot(n_rows, n_cols, 1);

    // Frequency response
    pylab.plot(x,fr, "blue");

    pylab.xlabel("Frequency (Hz)");
    pylab.ylabel("Frequency Response (dB)");

    // Phase response
    if(show_phase)
    {
        pylab.subplot(n_rows, n_cols, 2);

        Buffer pr = getPhaseResponse().getdB();

        pylab.plot(x,pr);

        pylab.xlabel("Frequency (Hz)");
        pylab.ylabel("Phase Response (dB)");
    }

    float64 ymax = fr.getMax();
    float64 height = ymax - -60.0;

    pylab.ylim(-60.0, ymax + 0.05 * height);
}

Member Data Documentation

float64 Nsound::FilterFlanger::frequency_

protected

Definition at line 127 of file FilterFlanger.h.

Referenced by filter(), FilterFlanger(), operator=(), and plot().

float64 Nsound::FilterFlanger::max_delay_

protected

Definition at line 128 of file FilterFlanger.h.

Referenced by filter(), FilterFlanger(), operator=(), and plot().

FilterDelay* Nsound::FilterFlanger::delay_

protected

Definition at line 129 of file FilterFlanger.h.

Referenced by filter(), FilterFlanger(), operator=(), reset(), and ~FilterFlanger().

Generator* Nsound::FilterFlanger::gen_

protected

Definition at line 130 of file FilterFlanger.h.

Referenced by filter(), FilterFlanger(), operator=(), reset(), and ~FilterFlanger().

float64 Nsound::Filter::sample_rate_

protectedinherited

Definition at line 113 of file Filter.h.

Referenced by Nsound::FilterPhaser::filter(), Nsound::FilterCombLowPassFeedback::filter(), Nsound::FilterDelay::filter(), Nsound::FilterAllPass::FilterAllPass(), Nsound::FilterCombLowPassFeedback::FilterCombLowPassFeedback(), Nsound::FilterDelay::FilterDelay(), FilterFlanger(), Nsound::FilterPhaser::FilterPhaser(), Nsound::FilterSlinky::FilterSlinky(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Filter::getPhaseResponse(), Nsound::Filter::getSampleRate(), Nsound::FilterStageIIR::makeIIRKernelHelper(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterStageIIR::makeKernel(), Nsound::FilterBandPassVocoder::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterParametricEqualizer::makeKernel(), Nsound::FilterPhaser::operator=(), Nsound::FilterLeastSquaresFIR::operator=(), operator=(), Nsound::FilterIIR::operator=(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterParametricEqualizer::plot(), Nsound::FilterLowPassIIR::setCutoff(), and Nsound::FilterLeastSquaresFIR::setWindow().

float64 Nsound::Filter::two_pi_over_sample_rate_

protectedinherited

Definition at line 114 of file Filter.h.

Referenced by Nsound::FilterTone::makeKernel(), Nsound::FilterLowPassFIR::makeKernel(), and Nsound::FilterParametricEqualizer::makeKernel().

float64 Nsound::Filter::sample_time_

protectedinherited

Definition at line 115 of file Filter.h.

Referenced by Nsound::FilterLowPassMoogVcf::_make_filter().

uint32 Nsound::Filter::kernel_size_

protectedinherited

Definition at line 116 of file Filter.h.

Referenced by Nsound::FilterLowPassFIR::filter(), Nsound::FilterLeastSquaresFIR::filter(), Nsound::FilterBandPassFIR::FilterBandPassFIR(), Nsound::FilterBandPassIIR::FilterBandPassIIR(), Nsound::FilterBandRejectIIR::FilterBandRejectIIR(), Nsound::FilterHighPassIIR::FilterHighPassIIR(), Nsound::FilterLeastSquaresFIR::FilterLeastSquaresFIR(), Nsound::FilterLowPassFIR::FilterLowPassFIR(), Nsound::FilterLowPassIIR::FilterLowPassIIR(), Nsound::FilterLeastSquaresFIR::getKernel(), Nsound::Filter::getKernelSize(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterLowPassFIR::makeKernel(), Nsound::FilterBandRejectFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterLowPassFIR::reset(), Nsound::FilterHighPassFIR::reset(), Nsound::FilterLeastSquaresFIR::reset(), Nsound::FilterLeastSquaresFIR::setKernel(), Nsound::FilterLeastSquaresFIR::setWindow(), and Nsound::FilterHighPassFIR::spectraReversal_().

bool Nsound::Filter::is_realtime_

protectedinherited

Definition at line 118 of file Filter.h.

Referenced by Nsound::Filter::filter(), Nsound::FilterBandRejectIIR::filter(), Nsound::FilterBandRejectFIR::filter(), Nsound::Filter::getImpulseResponse(), and Nsound::Filter::setRealtime().

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

• Nsound/FilterFlanger.h
• Nsound/FilterFlanger.cc