C++ Constant-Q

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

/*

    Constant-Q library

    Copyright (c) 2013-2014 Queen Mary, University of London

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

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

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*/

#ifndef CONSTANTQ_H

#define CONSTANTQ_H

#include "CQBase.h"

#include "CQParameters.h"

#include "CQKernel.h"

class Resampler;

class FFTReal;

/**

 * Calculate a complex sparse constant-Q representation from

 * time-domain input. The input of each \ref process call is a single

 * frame of time-domain samples; the output is a series of columns of

 * varying height. See \ref process for details.

 *

 * For a real (magnitude-only) interpolated dense representation, see

 * CQSpectrogram.

 */

class ConstantQ : public CQBase

{

public:

    /**

     * Construct a complex Constant-Q transform object using the given

     * transform parameters.

     */

    ConstantQ(CQParameters params);

    virtual ~ConstantQ();

    // CQBase methods, see CQBase.h for documentation

    virtual bool isValid() const { return m_kernel && m_kernel->isValid(); }

    virtual double getSampleRate() const { return m_sampleRate; }

    virtual int getBinsPerOctave() const { return m_binsPerOctave; }

    virtual int getOctaves() const { return m_octaves; }

    virtual int getTotalBins() const { return m_octaves * m_binsPerOctave; }

    virtual int getColumnHop() const { return m_p.fftHop / m_p.atomsPerFrame; }

    virtual int getLatency() const { return m_outputLatency; } 

    virtual double getMaxFrequency() const { return m_p.maxFrequency; }

    virtual double getMinFrequency() const;

    virtual double getBinFrequency(double bin) const; // bin may be nonintegral

    /**

     * Given a series of time-domain samples, return a series of

     * constant-Q columns. Any samples left over (that did not fit

     * into a constant-Q processing block) are saved for the next call

     * to process or getRemainingBlocks. 

     *

     * The input is assumed to be a single frame of time-domain sample

     * values, such that consecutive calls to \ref process receive

     * contiguous frames from the source signal. Each frame may be of

     * any length in samples.

     *

     * Each output column contains a series of constant-Q bin values

     * ordered from highest to lowest frequency.

     *

     * Output columns are of varying height: each will contain at

     * least getBinsPerOctave() values, because the highest-frequency

     * octave is always present, but a second octave (if requested)

     * will appear only in alternate columns, a third octave only in

     * every fourth column, and so on.

     *

     * If you need a format in which all columns are of equal height

     * and every bin contains a value, use \ref CQSpectrogram instead

     * of ConstantQ.

     */

    ComplexBlock process(const RealSequence &);

    /**

     * Return the remaining constant-Q columns following the end of

     * processing. Any buffered input is padded so as to ensure that

     * all input provided to process() will have been returned.

     */

    ComplexBlock getRemainingOutput();

private:

    const CQParameters m_inparams;

    const double m_sampleRate;

    const double m_maxFrequency;

    const double m_minFrequency;

    const int m_binsPerOctave;

    int m_octaves;

    CQKernel *m_kernel;

    CQKernel::Properties m_p;

    int m_bigBlockSize;

    std::vector<Resampler *> m_decimators;

    std::vector<RealSequence> m_buffers;

    int m_outputLatency;

    FFTReal *m_fft;

    void initialise();

    ComplexBlock processOctaveBlock(int octave);

    // Not provided

    ConstantQ(const ConstantQ &);

    ConstantQ &operator=(const ConstantQ &);

};

#endif