C++ Constant-Q

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*

    Constant-Q library

    Copyright (c) 2013-2015 Queen Mary, University of London

    Permission is hereby granted, free of charge, to any person

    obtaining a copy of this software and associated documentation

    files (the "Software"), to deal in the Software without

    restriction, including without limitation the rights to use, copy,

    modify, merge, publish, distribute, sublicense, and/or sell copies

    of the Software, and to permit persons to whom the Software is

    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be

    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY

    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF

    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the names of the Centre for

    Digital Music; Queen Mary, University of London; and Chris Cannam

    shall not be used in advertising or otherwise to promote the sale,

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    authorization.

*/

#ifndef CQCHROMAGRAM_H

#define CQCHROMAGRAM_H

#include "CQBase.h"

#include "CQParameters.h"

class CQSpectrogram;

class Chromagram

{

public:

    struct Parameters {

        Parameters(double sr) :

            sampleRate(sr),

            lowestOctave(0),

            octaveCount(7),

            binsPerOctave(36),

            tuningFrequency(440.),

            q(1.0),                    // Q scaling factor

            atomHopFactor(0.25),       // hop size of shortest temporal atom

            threshold(0.0005),         // sparsity threshold for resulting kernel

            window(CQParameters::SqrtBlackmanHarris) // window shape

        { }

        /**

         * Sampling rate of input signal.

         */

        double sampleRate;

        /**

         * Octave number of lowest octave to include in the

         * chromagram. Numbering is per ASA standard with -1 as the

         * first octave in the MIDI range and middle-C being C4. The

         * octave starts at C.

         */

        int lowestOctave;

        /**

         * Number of source constant-Q octaves to wrap around into the

         * single-octave chroma output.

         */

        int octaveCount;

        /**

         * Number of constant-Q transform bins per octave and the

         * number of bins in the chroma output.

         */

        int binsPerOctave;

        /**

         * Frequency of concert A, used when mapping the note-based

         * octave extents into frequency extents for the constant-Q

         * transform.

         */

        double tuningFrequency;

        /**

         * Spectral atom bandwidth scaling factor.

         */

        double q;

        /**

         * Hop size between temporal atoms, where 1 == no overlap and

         * smaller values indicate overlapping atoms.

         */

        double atomHopFactor;

        /**

         * Sparsity threshold for Constant-Q kernel: values with

         * magnitude smaller than this are truncated to zero.

         */

        double threshold;

        /**

         * Window shape to use for the Constant-Q kernel atoms.

         */

        CQParameters::WindowType window;

    };

    Chromagram(Parameters params);

    virtual ~Chromagram();

    CQBase::RealBlock process(const CQBase::RealSequence &);

    CQBase::RealBlock getRemainingOutput();

    double getMinFrequency() const { return m_minFrequency; }

    double getMaxFrequency() const { return m_maxFrequency; }

    std::string getBinName(int bin) const;

    bool isValid() const;

    int getColumnHop() const;

    int getLatency() const;

private:

    Parameters m_params;

    CQSpectrogram *m_cq;

    double m_minFrequency;

    double m_maxFrequency;

    CQBase::RealBlock convert(const CQBase::RealBlock &);

};

#endif