yuzu-android/src/audio_core/interpolate.h
2016-04-29 08:05:41 +01:00

42 lines
1.4 KiB
C++

// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <array>
#include <vector>
#include "common/common_types.h"
namespace AudioInterp {
/// A variable length buffer of signed PCM16 stereo samples.
using StereoBuffer16 = std::vector<std::array<s16, 2>>;
struct State {
// Two historical samples.
std::array<s16, 2> xn1 = {}; ///< x[n-1]
std::array<s16, 2> xn2 = {}; ///< x[n-2]
};
/**
* No interpolation. This is equivalent to a zero-order hold. There is a two-sample predelay.
* @param input Input buffer.
* @param rate_multiplier Stretch factor. Must be a positive non-zero value.
* rate_multiplier > 1.0 performs decimation and rate_multipler < 1.0 performs upsampling.
* @return The resampled audio buffer.
*/
StereoBuffer16 None(State& state, const StereoBuffer16& input, float rate_multiplier);
/**
* Linear interpolation. This is equivalent to a first-order hold. There is a two-sample predelay.
* @param input Input buffer.
* @param rate_multiplier Stretch factor. Must be a positive non-zero value.
* rate_multiplier > 1.0 performs decimation and rate_multipler < 1.0 performs upsampling.
* @return The resampled audio buffer.
*/
StereoBuffer16 Linear(State& state, const StereoBuffer16& input, float rate_multiplier);
} // namespace AudioInterp