c@119: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
c@119: /*
c@119:     Constant-Q library
c@119:     Copyright (c) 2013-2014 Queen Mary, University of London
c@119: 
c@119:     Permission is hereby granted, free of charge, to any person
c@119:     obtaining a copy of this software and associated documentation
c@119:     files (the "Software"), to deal in the Software without
c@119:     restriction, including without limitation the rights to use, copy,
c@119:     modify, merge, publish, distribute, sublicense, and/or sell copies
c@119:     of the Software, and to permit persons to whom the Software is
c@119:     furnished to do so, subject to the following conditions:
c@119: 
c@119:     The above copyright notice and this permission notice shall be
c@119:     included in all copies or substantial portions of the Software.
c@119: 
c@119:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
c@119:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
c@119:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
c@119:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
c@119:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
c@119:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
c@119:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
c@119: 
c@119:     Except as contained in this notice, the names of the Centre for
c@119:     Digital Music; Queen Mary, University of London; and Chris Cannam
c@119:     shall not be used in advertising or otherwise to promote the sale,
c@119:     use or other dealings in this Software without prior written
c@119:     authorization.
c@119: */
c@119: 
c@119: #ifndef RESAMPLER_H
c@119: #define RESAMPLER_H
c@119: 
c@119: #include <vector>
c@119: 
c@119: /**
c@119:  * Resampler resamples a stream from one integer sample rate to
c@119:  * another (arbitrary) rate, using a kaiser-windowed sinc filter.  The
c@119:  * results and performance are pretty similar to libraries such as
c@119:  * libsamplerate, though this implementation does not support
c@119:  * time-varying ratios (the ratio is fixed on construction).
c@119:  *
c@119:  * See also Decimator, which is faster and rougher but supports only
c@119:  * power-of-two downsampling factors.
c@119:  */
c@119: class Resampler
c@119: {
c@119: public:
c@119:     /**
c@119:      * Construct a Resampler to resample from sourceRate to
c@119:      * targetRate.
c@119:      */
c@119:     Resampler(int sourceRate, int targetRate);
c@119: 
c@119:     /**
c@119:      * Construct a Resampler to resample from sourceRate to
c@119:      * targetRate, using the given filter parameters.
c@119:      */
c@119:     Resampler(int sourceRate, int targetRate,
c@119:               double snr, double bandwidth);
c@119: 
c@119:     virtual ~Resampler();
c@119: 
c@119:     /**
c@119:      * Read n input samples from src and write resampled data to
c@119:      * dst. The return value is the number of samples written, which
c@119:      * will be no more than ceil((n * targetRate) / sourceRate). The
c@119:      * caller must ensure the dst buffer has enough space for the
c@119:      * samples returned.
c@119:      */
c@119:     int process(const double *src, double *dst, int n);
c@119: 
c@119:     /**
c@119:      * Read n input samples from src and return resampled data by
c@119:      * value.
c@119:      */
c@119:     std::vector<double> process(const double *src, int n);
c@119: 
c@119:     /**
c@119:      * Return the number of samples of latency at the output due by
c@119:      * the filter. (That is, the output will be delayed by this number
c@119:      * of samples relative to the input.)
c@119:      */
c@119:     int getLatency() const { return m_latency; }
c@119: 
c@119:     /**
c@119:      * Carry out a one-off resample of a single block of n
c@119:      * samples. The output is latency-compensated.
c@119:      */
c@119:     static std::vector<double> resample
c@119:     (int sourceRate, int targetRate, const double *data, int n);
c@119: 
c@119: private:
c@119:     int m_sourceRate;
c@119:     int m_targetRate;
c@119:     int m_gcd;
c@119:     int m_filterLength;
c@119:     int m_latency;
c@119:     double m_peakToPole;
c@119:     
c@119:     struct Phase {
c@119:         int nextPhase;
c@119:         std::vector<double> filter;
c@119:         int drop;
c@119:     };
c@119: 
c@119:     Phase *m_phaseData;
c@119:     int m_phase;
c@119:     std::vector<double> m_buffer;
c@119:     int m_bufferOrigin;
c@119: 
c@119:     void initialise(double, double);
c@119:     double reconstructOne();
c@119: };
c@119: 
c@119: #endif
c@119: