annotate constant-q-cpp/cq/CQSpectrogram.h @ 372:af71cbdab621 tip

Update bqvec code

/* -*- 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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    The above copyright notice and this permission notice shall be
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    Except as contained in this notice, the names of the Centre for
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*/

#ifndef CQSPECTROGRAM_H
#define CQSPECTROGRAM_H

#include "ConstantQ.h"

/**
 * Calculate a dense constant-Q magnitude spectrogram 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 fixed-height
 * columns. See \ref process for details.
 *
 * If you need the full complex-valued constant-Q output, you must use
 * the \ref ConstantQ class instead.
 */
class CQSpectrogram : public CQBase
{
public:
    enum Interpolation {
        /// leave empty cells as zero
	InterpolateZeros,
        /// replace empty cells with a repeat of the previous column
	InterpolateHold,
        /// perform linear interpolation between consecutive time cells
	InterpolateLinear,
    };

    /**
     * Construct a Constant-Q magnitude spectrogram object using the
     * given transform parameters.
     */
    CQSpectrogram(CQParameters params, Interpolation interpolation);
    virtual ~CQSpectrogram();

    // CQBase methods, see CQBase.h for documentation
    virtual bool isValid() const { return m_cq.isValid(); }
    virtual double getSampleRate() const { return m_cq.getSampleRate(); }
    virtual int getBinsPerOctave() const { return m_cq.getBinsPerOctave(); }
    virtual int getOctaves() const { return m_cq.getOctaves(); }
    virtual int getTotalBins() const { return m_cq.getTotalBins(); }
    virtual int getColumnHop() const { return m_cq.getColumnHop(); }
    virtual int getLatency() const { return m_cq.getLatency(); } 
    virtual double getMaxFrequency() const { return m_cq.getMaxFrequency(); }
    virtual double getMinFrequency() const { return m_cq.getMinFrequency(); }
    virtual double getBinFrequency(double bin) const { return m_cq.getBinFrequency(bin); }

    /**
     * Given a series of time-domain samples, return a series of
     * constant-Q magnitude 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 value
     * magnitudes, ordered from highest to lowest frequency.
     *  
     * The columns are all of the same height, but they might not all
     * be populated, depending on the interpolation mode: in
     * InterpolateZeros mode, the lower octaves (which are spaced more
     * widely in the raw constant-Q than the highest octave) will
     * contain zeros for the undefined values, but in the other
     * interpolation modes every cell will be filled.
     *
     * To obtain raw, complex constant-Q bin values, use the ConstantQ
     * class.
     */
    RealBlock process(const RealSequence &);

    /**
     * Return the remaining constant-Q magnitude 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.
     */
    RealBlock getRemainingOutput();

private:
    ConstantQ m_cq;
    Interpolation m_interpolation;

    RealBlock m_buffer;
    RealBlock postProcess(const ComplexBlock &, bool insist);
    RealBlock fetchHold(bool insist);
    RealBlock fetchLinear(bool insist);
    RealBlock linearInterpolated(const RealBlock &, int, int);
    RealColumn m_prevColumn;
};

#endif