Lime3DS/src/audio_core/codec.h
Subv d7459354f5 Audio: Use std::deque instead of std::vector for the audio buffer type (StereoBuffer16).
The current code inserts and deletes elements from the beginning of the audio buffer, which is very inefficient in an std::vector.

Profiling was done using VisualStudio2017's Performance Analyzer in Super Mario 3D Land.

Before this change: AudioInterp::Linear had 14.14% of the runtime (inclusive) and most of that time was spent in std::vector's insert implementation.
After this change: AudioInterp::Linear has 0.36% of the runtime (inclusive)
2017-09-25 18:31:37 -05:00

52 lines
1.8 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 <deque>
#include "common/common_types.h"
namespace Codec {
/// A variable length buffer of signed PCM16 stereo samples.
using StereoBuffer16 = std::deque<std::array<s16, 2>>;
/// See: Codec::DecodeADPCM
struct ADPCMState {
// Two historical samples from previous processed buffer,
// required for ADPCM decoding
s16 yn1; ///< y[n-1]
s16 yn2; ///< y[n-2]
};
/**
* @param data Pointer to buffer that contains ADPCM data to decode
* @param sample_count Length of buffer in terms of number of samples
* @param adpcm_coeff ADPCM coefficients
* @param state ADPCM state, this is updated with new state
* @return Decoded stereo signed PCM16 data, sample_count in length
*/
StereoBuffer16 DecodeADPCM(const u8* const data, const size_t sample_count,
const std::array<s16, 16>& adpcm_coeff, ADPCMState& state);
/**
* @param num_channels Number of channels
* @param data Pointer to buffer that contains PCM8 data to decode
* @param sample_count Length of buffer in terms of number of samples
* @return Decoded stereo signed PCM16 data, sample_count in length
*/
StereoBuffer16 DecodePCM8(const unsigned num_channels, const u8* const data,
const size_t sample_count);
/**
* @param num_channels Number of channels
* @param data Pointer to buffer that contains PCM16 data to decode
* @param sample_count Length of buffer in terms of number of samples
* @return Decoded stereo signed PCM16 data, sample_count in length
*/
StereoBuffer16 DecodePCM16(const unsigned num_channels, const u8* const data,
const size_t sample_count);
};