citra/src/audio_core/time_stretch.h

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// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <cstddef>
#include <memory>
#include <vector>
#include "common/common_types.h"
namespace AudioCore {
class TimeStretcher final {
public:
TimeStretcher();
~TimeStretcher();
/**
* Set sample rate for the samples that Process returns.
* @param sample_rate The sample rate.
*/
void SetOutputSampleRate(unsigned int sample_rate);
/**
* Add samples to be processed.
* @param sample_buffer Buffer of samples in interleaved stereo PCM16 format.
* @param num_samples Number of samples.
*/
void AddSamples(const s16* sample_buffer, size_t num_samples);
/// Flush audio remaining in internal buffers.
void Flush();
/// Resets internal state and clears buffers.
void Reset();
/**
* Does audio stretching and produces the time-stretched samples.
* Timer calculations use sample_delay to determine how much of a margin we have.
* @param sample_delay How many samples are buffered downstream of this module and haven't been
* played yet.
* @return Samples to play in interleaved stereo PCM16 format.
*/
std::vector<s16> Process(size_t sample_delay);
private:
struct Impl;
std::unique_ptr<Impl> impl;
/// INTERNAL: ratio = wallclock time / emulated time
double CalculateCurrentRatio();
/// INTERNAL: If we have too many or too few samples downstream, nudge ratio in the appropriate
/// direction.
double CorrectForUnderAndOverflow(double ratio, size_t sample_delay) const;
/// INTERNAL: Gets the time-stretched samples from SoundTouch.
std::vector<s16> GetSamples();
};
} // namespace AudioCore