Chris@366: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@366: /*
Chris@366:     Constant-Q library
Chris@366:     Copyright (c) 2013-2014 Queen Mary, University of London
Chris@366: 
Chris@366:     Permission is hereby granted, free of charge, to any person
Chris@366:     obtaining a copy of this software and associated documentation
Chris@366:     files (the "Software"), to deal in the Software without
Chris@366:     restriction, including without limitation the rights to use, copy,
Chris@366:     modify, merge, publish, distribute, sublicense, and/or sell copies
Chris@366:     of the Software, and to permit persons to whom the Software is
Chris@366:     furnished to do so, subject to the following conditions:
Chris@366: 
Chris@366:     The above copyright notice and this permission notice shall be
Chris@366:     included in all copies or substantial portions of the Software.
Chris@366: 
Chris@366:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@366:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@366:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
Chris@366:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
Chris@366:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@366:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@366:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@366: 
Chris@366:     Except as contained in this notice, the names of the Centre for
Chris@366:     Digital Music; Queen Mary, University of London; and Chris Cannam
Chris@366:     shall not be used in advertising or otherwise to promote the sale,
Chris@366:     use or other dealings in this Software without prior written
Chris@366:     authorization.
Chris@366: */
Chris@366: 
Chris@366: #ifndef CQINVERSE_H
Chris@366: #define CQINVERSE_H
Chris@366: 
Chris@366: #include "CQBase.h"
Chris@366: #include "CQKernel.h"
Chris@366: 
Chris@366: class Resampler;
Chris@366: class FFTReal;
Chris@366: 
Chris@366: /**
Chris@366:  * Calculate an inverse constant-Q transform. The input must be the
Chris@366:  * same representation as returned as output of a \ref ConstantQ
Chris@366:  * object with the same parameters. The output is a time-domain
Chris@366:  * signal.
Chris@366:  *
Chris@366:  * Note that you cannot perform an inverse transform from the
Chris@366:  * magnitude-only output of \ref CQSpectrogram; you need the complex
Chris@366:  * valued data from \ref ConstantQ.
Chris@366:  *
Chris@366:  * Our implementation of the Constant-Q transform is not exactly
Chris@366:  * invertible, and this produces only an approximation of the original
Chris@366:  * signal (see publications for details).
Chris@366:  */
Chris@366: class CQInverse : public CQBase
Chris@366: {
Chris@366: public:
Chris@366:     /**
Chris@366:      * Construct an inverse Constant-Q transform object using the
Chris@366:      * given transform parameters.
Chris@366:      */
Chris@366:     CQInverse(CQParameters params);
Chris@366:     virtual ~CQInverse();
Chris@366: 
Chris@366:     // CQBase methods, see CQBase.h for documentation
Chris@366:     virtual bool isValid() const { return m_kernel && m_kernel->isValid(); }
Chris@366:     virtual double getSampleRate() const { return m_sampleRate; }
Chris@366:     virtual int getBinsPerOctave() const { return m_binsPerOctave; }
Chris@366:     virtual int getOctaves() const { return m_octaves; }
Chris@366:     virtual int getTotalBins() const { return m_octaves * m_binsPerOctave; }
Chris@366:     virtual int getColumnHop() const { return m_p.fftHop / m_p.atomsPerFrame; }
Chris@366:     virtual int getLatency() const { return m_outputLatency; } 
Chris@366:     virtual double getMaxFrequency() const { return m_p.maxFrequency; }
Chris@366:     virtual double getMinFrequency() const; // actual min, not that passed to ctor
Chris@366:     virtual double getBinFrequency(double bin) const;
Chris@366: 
Chris@366:     /**
Chris@366:      * Given a series of constant-Q columns in the form produced by
Chris@366:      * the \ref ConstantQ class, return a series of time-domain
Chris@366:      * samples resulting from approximately inverting the constant-Q
Chris@366:      * transform.
Chris@366:      */
Chris@366:     RealSequence process(const ComplexBlock &);
Chris@366: 
Chris@366:     /**
Chris@366:      * Return the remaining time-domain samples following the end of
Chris@366:      * processing.
Chris@366:      */
Chris@366:     RealSequence getRemainingOutput();
Chris@366: 
Chris@366: private:
Chris@366:     const CQParameters m_inparams;
Chris@366:     const double m_sampleRate;
Chris@366:     const double m_maxFrequency;
Chris@366:     const double m_minFrequency;
Chris@366:     const int m_binsPerOctave;
Chris@366: 
Chris@366:     int m_octaves;
Chris@366:     CQKernel *m_kernel;
Chris@366:     CQKernel::Properties m_p;
Chris@366: 
Chris@366:     std::vector<Resampler *> m_upsamplers;
Chris@366:     std::vector<RealSequence> m_buffers;
Chris@366:     std::vector<RealSequence> m_olaBufs; // fixed-length, for overlap-add
Chris@366:     
Chris@366:     int m_outputLatency;
Chris@366: 
Chris@366:     FFTReal *m_fft;
Chris@366:     
Chris@366:     void initialise();
Chris@366:     void processOctave(int octave, const ComplexBlock &block);
Chris@366:     void processOctaveColumn(int octave, const ComplexColumn &column);
Chris@366:     void overlapAddAndResample(int octave, const RealSequence &);
Chris@366:     RealSequence drawFromBuffers();
Chris@366: };
Chris@366: 
Chris@366: #endif