view cq/CQBase.h @ 147:1060a19e2334

Report validity of CQKernel construction, and avoid NaN values for invalid parameters. Also documentation.

/* -*- 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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    obtaining a copy of this software and associated documentation
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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 CQBASE_H
#define CQBASE_H

#include <vector>
#include <complex>

/**
 * Interface class for Constant-Q implementations, containing common
 * type declarations and means to query configuration parameters.
 */
class CQBase
{
public:
    /// A single complex-valued sample.
    typedef std::complex<double> Complex;

    /// A series of real-valued samples ordered in time.
    typedef std::vector<double> RealSequence;

    /// A series of real-valued samples ordered by bin (frequency or similar).
    typedef std::vector<double> RealColumn;

    /// A series of complex-valued samples ordered in time.
    typedef std::vector<Complex> ComplexSequence;

    /// A series of complex-valued samples ordered by bin (frequency or similar).
    typedef std::vector<Complex> ComplexColumn;

    /// A matrix of real-valued samples, indexed by time then bin number.
    typedef std::vector<RealColumn> RealBlock;

    /// A matrix of complex-valued samples, indexed by time then bin number.
    typedef std::vector<ComplexColumn> ComplexBlock;

    /**
     * Return true if the Constant-Q implementation was successfully
     * constructed, with a valid set of initialisation parameters.
     */
    virtual bool isValid() const = 0;
    
    /**
     * Return the sample rate used when constructing the specific
     * Constant-Q implementation.
     */
    virtual double getSampleRate() const = 0;

    /**
     * Return the number of bins per octave specified when
     * constructing the Constant-Q implementation.
     */
    virtual int getBinsPerOctave() const = 0;

    /**
     * Return the number of octaves spanned by the Constant-Q
     * transform.
     */
    virtual int getOctaves() const = 0; 

    /**
     * Return the total number of bins in each Constant-Q column
     * (i.e. bins-per-octave times number of octaves).
     */
    virtual int getTotalBins() const = 0;

    /**
     * Return the spacing, in samples at the sample rate returned from
     * getSampleRate(), between one column and the next.
     */
    virtual int getColumnHop() const = 0;

    /**
     * Return the latency of Constant-Q calculation, in samples at the
     * sample rate returned from getSampleRate().
     */
    virtual int getLatency() const = 0;

    /**
     * Return the maximum frequency of the Constant-Q output, i.e. the
     * frequency of the highest bin in the output. This will normally
     * be the same as the maximum frequency passed to the constructor
     * of the specific Constant-Q implementation.
     */
    virtual double getMaxFrequency() const = 0;

    /**
     * Return the minimum frequency of the Constant-Q output, i.e. the
     * frequency of the lowest bin in the output. This is derived from
     * the maximum frequency and octave count, and is not necessarily
     * the same as any minimum frequency requested when constructing
     * the Constant-Q implementation.
     */
    virtual double getMinFrequency() const = 0;

    /**
     * Return the frequency of a given bin in the Constant-Q
     * output. This actually maps a continuous "bin scale" value to 
     * frequency: the bin parameter does not have to be an integer.
     */
    virtual double getBinFrequency(double bin) const = 0;
};

#endif