Chris@738: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@738: 
Chris@738: /*
Chris@738:     Sonic Visualiser
Chris@738:     An audio file viewer and annotation editor.
Chris@738:     Centre for Digital Music, Queen Mary, University of London.
Chris@738:     
Chris@738:     This program is free software; you can redistribute it and/or
Chris@738:     modify it under the terms of the GNU General Public License as
Chris@738:     published by the Free Software Foundation; either version 2 of the
Chris@738:     License, or (at your option) any later version.  See the file
Chris@738:     COPYING included with this distribution for more information.
Chris@738: */
Chris@738: 
Chris@738: #ifndef SV_TIME_STRETCH_WRAPPER_H
Chris@738: #define SV_TIME_STRETCH_WRAPPER_H
Chris@738: 
Chris@738: #include "bqaudioio/ApplicationPlaybackSource.h"
Chris@738: 
Chris@738: #include "base/BaseTypes.h"
Chris@738: 
Chris@738: #include <vector>
Chris@738: #include <mutex>
Chris@738: 
Chris@738: namespace RubberBand {
Chris@738:     class RubberBandStretcher;
Chris@738: }
Chris@738: 
Chris@738: /**
Chris@738:  * A breakfastquay::ApplicationPlaybackSource wrapper that implements
Chris@738:  * time-stretching using Rubber Band. Note that the stretcher is
Chris@738:  * bypassed entirely when a ratio of 1.0 is set; this means it's
Chris@738:  * (almost) free to use one of these wrappers normally, but it also
Chris@738:  * means you can't switch from 1.0 to another ratio (or back again)
Chris@738:  * without some audible artifacts.
Chris@738:  *
Chris@738:  * This is real-time safe while the ratio is fixed, and may perform
Chris@738:  * reallocations when the ratio changes.
Chris@738:  */
Chris@738: class TimeStretchWrapper : public breakfastquay::ApplicationPlaybackSource
Chris@738: {
Chris@738: public:
Chris@738:     /**
Chris@738:      * Create a wrapper around the given ApplicationPlaybackSource,
Chris@738:      * implementing another ApplicationPlaybackSource interface that
Chris@738:      * draws from the same source data but with a time-stretcher
Chris@738:      * optionally applied.
Chris@738:      *
Chris@738:      * The wrapper does not take ownership of the wrapped
Chris@738:      * ApplicationPlaybackSource, whose lifespan must exceed that of
Chris@738:      * this object.    
Chris@738:      */
Chris@738:     TimeStretchWrapper(ApplicationPlaybackSource *source);
Chris@738:     ~TimeStretchWrapper();
Chris@738: 
Chris@738:     /**
Chris@738:      * Set a time stretch factor, i.e. playback speed, where 1.0 is
Chris@738:      * normal speed
Chris@738:      */
Chris@738:     void setTimeStretchRatio(double ratio);
Chris@738: 
Chris@738:     /**
Chris@738:      * Clear stretcher buffers.
Chris@738:      */
Chris@738:     void reset();
Chris@738: 
Chris@738:     // These functions are passed through to the wrapped
Chris@738:     // ApplicationPlaybackSource
Chris@738:     
Chris@738:     std::string getClientName() const override;
Chris@738:     int getApplicationSampleRate() const override;
Chris@738:     int getApplicationChannelCount() const override;
Chris@738: 
Chris@738:     void setSystemPlaybackBlockSize(int) override;
Chris@738:     void setSystemPlaybackSampleRate(int) override;
Chris@738:     void setSystemPlaybackChannelCount(int) override;
Chris@738:     void setSystemPlaybackLatency(int) override;
Chris@738: 
Chris@738:     void setOutputLevels(float peakLeft, float peakRight) override;
Chris@738:     void audioProcessingOverload() override;
Chris@738: 
Chris@738:     /** 
Chris@738:      * Request some samples from the wrapped
Chris@738:      * ApplicationPlaybackSource, time-stretch if appropriate, and
Chris@738:      * return them to the target
Chris@738:      */
Chris@738:     int getSourceSamples(float *const *samples, int nchannels, int nframes)
Chris@738:         override;
Chris@738: 
Chris@738: private:
Chris@738:     ApplicationPlaybackSource *m_source;
Chris@738:     RubberBand::RubberBandStretcher *m_stretcher;
Chris@738:     double m_timeRatio;
Chris@738:     std::vector<std::vector<float>> m_inputs;
Chris@738:     std::mutex m_mutex;
Chris@740:     int m_stretcherInputSize;
Chris@738:     int m_channelCount;
Chris@738:     sv_samplerate_t m_sampleRate;
Chris@738: 
Chris@738:     void checkStretcher(); // call without m_mutex held
Chris@738:     
Chris@738:     TimeStretchWrapper(const TimeStretchWrapper &)=delete;
Chris@738:     TimeStretchWrapper &operator=(const TimeStretchWrapper &)=delete;
Chris@738: };
Chris@738: 
Chris@738: #endif
Chris@738: 
Chris@738: