Nsound::FilterSlinky Class Reference

Base class for IIR Filters, defines the interface. More...

#include <Nsound/FilterSlinky.h>

Inheritance diagram for Nsound::FilterSlinky:

Public Member Functions
	FilterSlinky (const float64 &sample_rate, const float64 &delay_time, const float64 &frequency_window)
virtual	~FilterSlinky ()
AudioStream	filter (const AudioStream &x)
AudioStream	filter (const AudioStream &x, const Buffer &frequencies)
Buffer	filter (const Buffer &x)
Buffer	filter (const Buffer &x, const Buffer &frequencies)
float64	filter (const float64 &x)
float64	filter (const float64 &x, const float64 &frequency)
void	reset ()
void	setRealtime (bool flag)
AudioStream	filter (const AudioStream &x, const float64 &frequency)
Buffer	filter (const Buffer &x, const float64 &frequency)
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 Types
typedef std::vector < FilterDelay * >	DelayVector
typedef std::vector < FilterBandPassIIR * >	FilterVector

Protected Attributes
DelayVector	delay_lines_
FilterVector	filters_
float64	sample_rate_
float64	two_pi_over_sample_rate_
float64	sample_time_
uint32	kernel_size_
bool	is_realtime_

Detailed Description

Base class for IIR Filters, defines the interface.

Definition at line 53 of file FilterSlinky.h.

Member Typedef Documentation

typedef std::vector< FilterDelay * > Nsound::FilterSlinky::DelayVector

protected

Definition at line 87 of file FilterSlinky.h.

typedef std::vector< FilterBandPassIIR * > Nsound::FilterSlinky::FilterVector

protected

Definition at line 88 of file FilterSlinky.h.

Constructor & Destructor Documentation

FilterSlinky::FilterSlinky	(	const float64 &	sample_rate,
		const float64 &	delay_time,
		const float64 &	frequency_window
	)

Definition at line 45 of file FilterSlinky.cc.

References delay_lines_, filters_, and Nsound::Filter::sample_rate_.

    :
    Filter(sample_rate),
    delay_lines_(),
    filters_()
{
    float64 f = 0.0;

    while( f < sample_rate_ / 2.0)
    {
        if(f == 0.0)
        {
            f = frequency_octave;
        }
        else
        {
            f += frequency_octave;
        }
    }

    // Create the highest frequency pass band filter.

    float64 f_high = f;
    f -= frequency_octave;
    float64 f_low  = f;

    filters_.push_back(
        new FilterBandPassIIR(
            sample_rate_,
            6,
            f_low,
            f_high,
            0.01));

    // Create pass band filters for the remaing frequency octaves.
    float64 dt = delay_octave;
    while(f >= frequency_octave)
    {
        f_high = f;
        f -= frequency_octave;
        f_low = f;

        if(f_high == frequency_octave)
        {
            f_low = 0.0;
        }

        filters_.push_back(
        new FilterBandPassIIR(
            sample_rate_,
            6,
            f_low,
            f_high,
            0.01));

        delay_lines_.push_back(
            new FilterDelay(sample_rate_, dt));

        dt += delay_octave;
    }

//~    cout << "n_filters = " << filters_.size() << endl
//~         << "n_delays  = " << delay_lines_.size() << endl;
}

FilterSlinky::~FilterSlinky ( )

virtual

Definition at line 115 of file FilterSlinky.cc.

References delay_lines_, filter(), and filters_.

{
    FilterVector::iterator filter = filters_.begin();
    FilterVector::iterator end    = filters_.end();

    DelayVector::iterator delay = delay_lines_.begin();

    delete *filter;
    ++filter;

    while(filter != end)
    {
        delete *filter;
        delete *delay;

        ++filter;
        ++delay;
    }
}

Member Function Documentation

AudioStream FilterSlinky::filter

(

const AudioStream &

x

)

Definition at line 138 of file FilterSlinky.cc.

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

Referenced by filter(), reset(), and ~FilterSlinky().

{
    uint32 n_channels = x.getNChannels();

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

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

    return y;
}

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

Definition at line 154 of file FilterSlinky.cc.

References filter().

{
    return FilterSlinky::filter(x);
}

Buffer FilterSlinky::filter

(

const Buffer &

x

)

Definition at line 161 of file FilterSlinky.cc.

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

{
    Buffer y;

    uint32 n_samples = x.getLength();

    for(uint32 n = 0; n < n_samples; ++n)
    {
        y << FilterSlinky::filter(x[n]);
    }

    return y;
}

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

Definition at line 177 of file FilterSlinky.cc.

References filter().

{
    return FilterSlinky::filter(x);
}

float64 FilterSlinky::filter ( const float64 &  x )

virtual

Implements Nsound::Filter.

Definition at line 184 of file FilterSlinky.cc.

References delay_lines_, filter(), and filters_.

{
    float64 y = 0.0;

    FilterVector::iterator filter = filters_.begin();
    FilterVector::iterator end    = filters_.end();

    DelayVector::iterator delay = delay_lines_.begin();

    // There is always one more filter than delay lines, this is because the
    // highest frequency have zero delay.

    y += (*filter)->filter(x);

    ++filter;

    while(filter != end)
    {
        y += (*delay)->filter((*filter)->filter(x));

        ++filter;
        ++delay;
    }

    return y;
}

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

virtual

Implements Nsound::Filter.

Definition at line 213 of file FilterSlinky.cc.

References filter().

{
    return FilterSlinky::filter(x);
}

void FilterSlinky::reset ( )

virtual

Implements Nsound::Filter.

Definition at line 220 of file FilterSlinky.cc.

References delay_lines_, filter(), and filters_.

{
    FilterVector::iterator filter = filters_.begin();
    FilterVector::iterator end  = filters_.end();

    DelayVector::iterator delay = delay_lines_.begin();

    (*filter)->reset();
    ++filter;

    while(filter != end)
    {
        (*filter)->reset();
        (*delay)->reset();

        ++filter;
        ++delay;
    }

}

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 float64 &  frequency  )

inherited

Definition at line 76 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 float64 &  frequency  )

inherited

Definition at line 140 of file Filter.cc.

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

{
    if(!is_realtime_) reset();

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

    Buffer y(x.getLength());

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

        ++itor;
    }

    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(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterBandRejectIIR::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

DelayVector Nsound::FilterSlinky::delay_lines_

protected

Definition at line 90 of file FilterSlinky.h.

Referenced by filter(), FilterSlinky(), reset(), and ~FilterSlinky().

FilterVector Nsound::FilterSlinky::filters_

protected

Definition at line 91 of file FilterSlinky.h.

Referenced by filter(), FilterSlinky(), reset(), and ~FilterSlinky().

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(), Nsound::FilterFlanger::FilterFlanger(), Nsound::FilterPhaser::FilterPhaser(), 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=(), Nsound::FilterFlanger::operator=(), Nsound::FilterIIR::operator=(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandPassIIR::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/FilterSlinky.h
• Nsound/FilterSlinky.cc