mirror of
https://github.com/rodamaral/lsnes.git
synced 2025-04-02 10:42:15 -04:00
84 lines
3.6 KiB
C++
84 lines
3.6 KiB
C++
/***************************************************************************
|
|
* Copyright (C) 2008 by Sindre Aamås *
|
|
* sinamas@users.sourceforge.net *
|
|
* *
|
|
* This program is free software; you can redistribute it and/or modify *
|
|
* it under the terms of the GNU General Public License version 2 as *
|
|
* published by the Free Software Foundation. *
|
|
* *
|
|
* This program is distributed in the hope that it will be useful, *
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
|
|
* GNU General Public License version 2 for more details. *
|
|
* *
|
|
* You should have received a copy of the GNU General Public License *
|
|
* version 2 along with this program; if not, write to the *
|
|
* Free Software Foundation, Inc., *
|
|
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
|
|
***************************************************************************/
|
|
#ifndef RESAMPLER_H
|
|
#define RESAMPLER_H
|
|
|
|
#include <cstddef>
|
|
|
|
class Resampler {
|
|
public:
|
|
/** Returns the sampling rate of the input that this resampler expects. */
|
|
long inRate() const { return inRate_; }
|
|
|
|
/** Returns the approximate sampling rate of the output. */
|
|
long outRate() const { return outRate_; }
|
|
|
|
/**
|
|
* Can be used to adjust the input and output sampling rates slightly with minimal
|
|
* disturbance in the output.
|
|
*
|
|
* Should only be used for slight changes or the quality could detoriate. It can for
|
|
* instance be useful to tweak the output rate slightly to synchronize production speed
|
|
* to playback speed when synchronizing video frame rate to refresh rate while playing
|
|
* back audio from the same source. This can reduce skipped or duplicated video frames
|
|
* (or avoid audio underruns if no frame skipping is done).
|
|
*
|
|
* @param inRate New input sampling rate.
|
|
* @param outRate Desired new output sampling rate.
|
|
*/
|
|
virtual void adjustRate(long inRate, long outRate) = 0;
|
|
|
|
/**
|
|
* Returns the exact ratio that this resampler is configured to use, such that the actual
|
|
* output sampling rate is input_rate * mul / div.
|
|
*
|
|
* outRate() and inRate() are not necessarily equal to mul and div.
|
|
*
|
|
* Many resamplers are intended for real-time purposes where it does not matter much
|
|
* whether the output sampling rate is 100% exact.
|
|
*/
|
|
virtual void exactRatio(unsigned long &mul, unsigned long &div) const = 0;
|
|
|
|
/**
|
|
* Returns an upper bound on how many samples are produced for 'inlen' input samples.
|
|
* Can be used to calculate buffer sizes.
|
|
*/
|
|
virtual std::size_t maxOut(std::size_t inlen) const = 0;
|
|
|
|
/**
|
|
* Resamples the samples in 'in' and puts the resulting samples in 'out'.
|
|
*
|
|
* @param inlen The number of samples in 'in' to be resampled/consumed.
|
|
* @return The number of samples produced in 'out'.
|
|
*/
|
|
virtual std::size_t resample(short *out, short const *in, std::size_t inlen) = 0;
|
|
|
|
virtual ~Resampler() {}
|
|
|
|
protected:
|
|
Resampler() : inRate_(0), outRate_(0) {}
|
|
Resampler(long inRate, long outRate) : inRate_(inRate), outRate_(outRate) {}
|
|
void setRate(long inRate, long outRate) { inRate_ = inRate; outRate_ = outRate; }
|
|
|
|
private:
|
|
long inRate_;
|
|
long outRate_;
|
|
};
|
|
|
|
#endif
|