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