Chris@337: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@337: 
Chris@337: /*
Chris@337:     Vamp
Chris@337: 
Chris@337:     An API for audio analysis and feature extraction plugins.
Chris@337: 
Chris@337:     Centre for Digital Music, Queen Mary, University of London.
Chris@337:     Copyright 2006-2012 Chris Cannam and QMUL.
Chris@337:   
Chris@337:     Permission is hereby granted, free of charge, to any person
Chris@337:     obtaining a copy of this software and associated documentation
Chris@337:     files (the "Software"), to deal in the Software without
Chris@337:     restriction, including without limitation the rights to use, copy,
Chris@337:     modify, merge, publish, distribute, sublicense, and/or sell copies
Chris@337:     of the Software, and to permit persons to whom the Software is
Chris@337:     furnished to do so, subject to the following conditions:
Chris@337: 
Chris@337:     The above copyright notice and this permission notice shall be
Chris@337:     included in all copies or substantial portions of the Software.
Chris@337: 
Chris@337:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@337:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@337:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
Chris@337:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
Chris@337:     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@337:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@337:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@337: 
Chris@337:     Except as contained in this notice, the names of the Centre for
Chris@337:     Digital Music; Queen Mary, University of London; and Chris Cannam
Chris@337:     shall not be used in advertising or otherwise to promote the sale,
Chris@337:     use or other dealings in this Software without prior written
Chris@337:     authorization.
Chris@337: */
Chris@337: 
Chris@337: #ifndef _VAMP_FFT_H_
Chris@337: #define _VAMP_FFT_H_
Chris@337: 
Chris@337: #include "plugguard.h"
Chris@337: _VAMP_SDK_PLUGSPACE_BEGIN(FFT.h)
Chris@337: 
Chris@337: namespace Vamp {
Chris@337: 
Chris@337: /**
Chris@337:  * A simple FFT implementation provided for convenience of plugin
Chris@434:  * authors. This class provides one-shot (i.e. fixed table state is
Chris@445:  * recalculated every time) double-precision complex-complex
Chris@434:  * transforms. For repeated transforms from real time-domain data, use
Chris@446:  * an FFTComplex or FFTReal object instead.
Chris@446:  *
Chris@446:  * Note: If the SDK has been compiled with the SINGLE_PRECISION_FFT
Chris@446:  * flag, then all FFTs will use single precision internally. The
Chris@446:  * default is double precision. The API uses doubles in either case.
Chris@337:  *
Chris@434:  * The forward transform is unscaled; the inverse transform is scaled
Chris@434:  * by 1/n.
Chris@337:  */
Chris@337: class FFT
Chris@337: {
Chris@337: public:
Chris@337:     /**
Chris@434:      * Calculate a one-shot forward transform of size n.
Chris@446:      * n must be a multiple of 2.
Chris@337:      *
Chris@337:      * ri and ii must point to the real and imaginary component arrays
Chris@337:      * of the input. For real input, ii may be NULL.
Chris@337:      *
Chris@337:      * ro and io must point to enough space to receive the real and
Chris@337:      * imaginary component arrays of the output.
Chris@337:      *
Chris@337:      * All input and output arrays are of size n.
Chris@337:      */
Chris@338:     static void forward(unsigned int n,
Chris@338:                         const double *ri, const double *ii,
Chris@338:                         double *ro, double *io);
Chris@337: 
Chris@337:     /**
Chris@434:      * Calculate a one-shot inverse transform of size n.
Chris@394:      * n must be a power of 2, greater than 1.
Chris@337:      *
Chris@337:      * ri and ii must point to the real and imaginary component arrays
Chris@337:      * of the input. For real input, ii may be NULL.
Chris@337:      *
Chris@337:      * ro and io must point to enough space to receive the real and
Chris@337:      * imaginary component arrays of the output. The output is scaled
Chris@337:      * by 1/n. The output pointers may not be NULL, even if the output
Chris@337:      * is expected to be real.
Chris@337:      *
Chris@337:      * All input and output arrays are of size n.
Chris@337:      */
Chris@338:     static void inverse(unsigned int n,
Chris@338:                         const double *ri, const double *ii,
Chris@338:                         double *ro, double *io);
Chris@337: };
Chris@337: 
Chris@434: /**
Chris@434:  * A simple FFT implementation provided for convenience of plugin
Chris@446:  * authors. This class provides double-precision complex-complex
Chris@446:  * transforms.
Chris@446:  *
Chris@446:  * Note: If the SDK has been compiled with the SINGLE_PRECISION_FFT
Chris@446:  * flag, then all FFTs will use single precision internally. The
Chris@446:  * default is double precision. The API uses doubles in either case.
Chris@446:  *
Chris@446:  * The forward transform is unscaled; the inverse transform is scaled
Chris@446:  * by 1/n.
Chris@446:  */
Chris@446: class FFTComplex
Chris@446: {
Chris@448: public:
Chris@446:     /**
Chris@446:      * Prepare to calculate transforms of size n.
Chris@446:      * n must be a multiple of 2.
Chris@446:      */
Chris@446:     FFTComplex(unsigned int n);
Chris@446: 
Chris@446:     ~FFTComplex();
Chris@446: 
Chris@446:     /**
Chris@446:      * Calculate a forward transform of size n.
Chris@446:      *
Chris@446:      * ci must point to the interleaved complex input data of size n
Chris@446:      * (that is, 2n doubles in total).
Chris@446:      *
Chris@446:      * co must point to enough space to receive an interleaved complex
Chris@446:      * output array of size n (that is, 2n doubles in total).
Chris@446:      */
Chris@446:     void forward(const double *ci, double *co);
Chris@446: 
Chris@446:     /**
Chris@446:      * Calculate an inverse transform of size n.
Chris@446:      *
Chris@446:      * ci must point to an interleaved complex input array of size n
Chris@446:      * (that is, 2n doubles in total).
Chris@446:      *
Chris@446:      * co must point to enough space to receive the interleaved
Chris@446:      * complex output data of size n (that is, 2n doubles in
Chris@446:      * total). The output is scaled by 1/n.
Chris@446:      */
Chris@446:     void inverse(const double *ci, double *co);
Chris@446: 
Chris@446: private:
Chris@446:     class D;
Chris@446:     D *m_d;
Chris@446: };
Chris@446: 
Chris@446: /**
Chris@446:  * A simple FFT implementation provided for convenience of plugin
Chris@445:  * authors. This class provides transforms between double-precision
Chris@445:  * real time-domain and double-precision complex frequency-domain
Chris@445:  * data.
Chris@434:  *
Chris@446:  * Note: If the SDK has been compiled with the SINGLE_PRECISION_FFT
Chris@446:  * flag, then all FFTs will use single precision internally. The
Chris@446:  * default is double precision. The API uses doubles in either case.
Chris@446:  *
Chris@434:  * The forward transform is unscaled; the inverse transform is scaled
Chris@434:  * by 1/n.
Chris@434:  */
Chris@434: class FFTReal
Chris@434: {
Chris@448: public:
Chris@434:     /**
Chris@434:      * Prepare to calculate transforms of size n.
Chris@446:      * n must be a multiple of 2.
Chris@434:      */
Chris@434:     FFTReal(unsigned int n);
Chris@434: 
Chris@434:     ~FFTReal();
Chris@434: 
Chris@434:     /**
Chris@434:      * Calculate a forward transform of size n.
Chris@434:      *
Chris@434:      * ri must point to the real input data of size n.
Chris@434:      *
Chris@434:      * co must point to enough space to receive an interleaved complex
Chris@446:      * output array of size n/2+1 (that is, n+2 doubles in total).
Chris@434:      */
Chris@445:     void forward(const double *ri, double *co);
Chris@434: 
Chris@434:     /**
Chris@434:      * Calculate an inverse transform of size n.
Chris@434:      *
Chris@446:      * ci must point to an interleaved complex input array of size
Chris@446:      * n/2+1 (that is, n+2 doubles in total).
Chris@434:      *
Chris@434:      * ro must point to enough space to receive the real output data
Chris@434:      * of size n. The output is scaled by 1/n and only the real part
Chris@434:      * is returned.
Chris@434:      */
Chris@445:     void inverse(const double *ci, double *ro);
Chris@434: 
Chris@434: private:
Chris@434:     class D;
Chris@434:     D *m_d;
Chris@434: };
Chris@434: 
Chris@337: }
Chris@337: 
Chris@337: _VAMP_SDK_PLUGSPACE_END(FFT.h)
Chris@337: 
Chris@337: #endif