49 lines
1.7 KiB
C++
49 lines
1.7 KiB
C++
// Copyright 2016 Citra Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <array>
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#include <deque>
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#include "audio_core/audio_types.h"
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#include "common/common_types.h"
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namespace AudioCore::AudioInterp {
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/// A variable length buffer of signed PCM16 stereo samples.
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using StereoBuffer16 = std::deque<std::array<s16, 2>>;
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struct State {
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/// Two historical samples.
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std::array<s16, 2> xn1 = {}; ///< x[n-1]
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std::array<s16, 2> xn2 = {}; ///< x[n-2]
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/// Current fractional position.
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u64 fposition = 0;
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};
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/**
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* No interpolation. This is equivalent to a zero-order hold. There is a two-sample predelay.
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* @param state Interpolation state.
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* @param input Input buffer.
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* @param rate Stretch factor. Must be a positive non-zero value.
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* rate > 1.0 performs decimation and rate < 1.0 performs upsampling.
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* @param output The resampled audio buffer.
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* @param outputi The index of output to start writing to.
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*/
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void None(State& state, StereoBuffer16& input, float rate, StereoFrame16& output,
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std::size_t& outputi);
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/**
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* Linear interpolation. This is equivalent to a first-order hold. There is a two-sample predelay.
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* @param state Interpolation state.
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* @param input Input buffer.
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* @param rate Stretch factor. Must be a positive non-zero value.
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* rate > 1.0 performs decimation and rate < 1.0 performs upsampling.
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* @param output The resampled audio buffer.
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* @param outputi The index of output to start writing to.
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*/
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void Linear(State& state, StereoBuffer16& input, float rate, StereoFrame16& output,
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std::size_t& outputi);
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} // namespace AudioCore::AudioInterp
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