XAudio2学习之内置音效：混响

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XAudio2提供了两种内置音频特效，这两种音频特效以及它们的创建方式如下：

1.创建XAPO对象；

2.创建XAPO对象描述结构体对象，用于对XAPO信息进行描述；

3.创建效果链结构体对象，用于持有描述结构体对象：包括两个成员变量：一个是持有的对象个数，一个是所有对象的数组；

4.将效果链传递给XAudio2；

5.释放XAPO对象；

6.创建音效参数结构体对象，并设置需要的值；

7.将参数结构体对象传递给XAudio2对象；

8.启用或者禁用效果。

对于参数结构体各个成员变量，上一篇文章也有说明，如果觉得我表达的不准确，可以去查看MSDN或者DirectX 手册。对于每个结构体成员变量的取值，都是有范围的，XAduio2也提供了缺省值，具体如下：

// XAUDIO2FX_REVERB_PARAMETERS: Native parameter set for the reverb effect

typedef struct XAUDIO2FX_REVERB_PARAMETERS
{
    // ratio of wet (processed) signal to dry (original) signal
    float WetDryMix;            // [0, 100] (percentage)

    // Delay times
    UINT32 ReflectionsDelay;    // [0, 300] in ms
    BYTE ReverbDelay;           // [0, 85] in ms
    BYTE RearDelay;             // [0, 5] in ms

    // Indexed parameters
    BYTE PositionLeft;          // [0, 30] no units
    BYTE PositionRight;         // [0, 30] no units, ignored when configured to mono
    BYTE PositionMatrixLeft;    // [0, 30] no units
    BYTE PositionMatrixRight;   // [0, 30] no units, ignored when configured to mono
    BYTE EarlyDiffusion;        // [0, 15] no units
    BYTE LateDiffusion;         // [0, 15] no units
    BYTE LowEQGain;             // [0, 12] no units
    BYTE LowEQCutoff;           // [0, 9] no units
    BYTE HighEQGain;            // [0, 8] no units
    BYTE HighEQCutoff;          // [0, 14] no units

    // Direct parameters
    float RoomFilterFreq;       // [20, 20000] in Hz
    float RoomFilterMain;       // [-100, 0] in dB
    float RoomFilterHF;         // [-100, 0] in dB
    float ReflectionsGain;      // [-100, 20] in dB
    float ReverbGain;           // [-100, 20] in dB
    float DecayTime;            // [0.1, inf] in seconds
    float Density;              // [0, 100] (percentage)
    float RoomSize;             // [1, 100] in feet

    // component control
    BOOL DisableLateField;      // TRUE to disable late field reflections
} XAUDIO2FX_REVERB_PARAMETERS;


// Maximum, minimum and default values for the parameters above
#define XAUDIO2FX_REVERB_MIN_WET_DRY_MIX            0.0f
#define XAUDIO2FX_REVERB_MIN_REFLECTIONS_DELAY      0
#define XAUDIO2FX_REVERB_MIN_REVERB_DELAY           0
#define XAUDIO2FX_REVERB_MIN_REAR_DELAY             0
#define XAUDIO2FX_REVERB_MIN_POSITION               0
#define XAUDIO2FX_REVERB_MIN_DIFFUSION              0
#define XAUDIO2FX_REVERB_MIN_LOW_EQ_GAIN            0
#define XAUDIO2FX_REVERB_MIN_LOW_EQ_CUTOFF          0
#define XAUDIO2FX_REVERB_MIN_HIGH_EQ_GAIN           0
#define XAUDIO2FX_REVERB_MIN_HIGH_EQ_CUTOFF         0
#define XAUDIO2FX_REVERB_MIN_ROOM_FILTER_FREQ       20.0f
#define XAUDIO2FX_REVERB_MIN_ROOM_FILTER_MAIN       -100.0f
#define XAUDIO2FX_REVERB_MIN_ROOM_FILTER_HF         -100.0f
#define XAUDIO2FX_REVERB_MIN_REFLECTIONS_GAIN       -100.0f
#define XAUDIO2FX_REVERB_MIN_REVERB_GAIN            -100.0f
#define XAUDIO2FX_REVERB_MIN_DECAY_TIME             0.1f
#define XAUDIO2FX_REVERB_MIN_DENSITY                0.0f
#define XAUDIO2FX_REVERB_MIN_ROOM_SIZE              0.0f

#define XAUDIO2FX_REVERB_MAX_WET_DRY_MIX            100.0f
#define XAUDIO2FX_REVERB_MAX_REFLECTIONS_DELAY      300
#define XAUDIO2FX_REVERB_MAX_REVERB_DELAY           85
#define XAUDIO2FX_REVERB_MAX_REAR_DELAY             5
#define XAUDIO2FX_REVERB_MAX_POSITION               30
#define XAUDIO2FX_REVERB_MAX_DIFFUSION              15
#define XAUDIO2FX_REVERB_MAX_LOW_EQ_GAIN            12
#define XAUDIO2FX_REVERB_MAX_LOW_EQ_CUTOFF          9
#define XAUDIO2FX_REVERB_MAX_HIGH_EQ_GAIN           8
#define XAUDIO2FX_REVERB_MAX_HIGH_EQ_CUTOFF         14
#define XAUDIO2FX_REVERB_MAX_ROOM_FILTER_FREQ       20000.0f
#define XAUDIO2FX_REVERB_MAX_ROOM_FILTER_MAIN       0.0f
#define XAUDIO2FX_REVERB_MAX_ROOM_FILTER_HF         0.0f
#define XAUDIO2FX_REVERB_MAX_REFLECTIONS_GAIN       20.0f
#define XAUDIO2FX_REVERB_MAX_REVERB_GAIN            20.0f
#define XAUDIO2FX_REVERB_MAX_DENSITY                100.0f
#define XAUDIO2FX_REVERB_MAX_ROOM_SIZE              100.0f

#define XAUDIO2FX_REVERB_DEFAULT_WET_DRY_MIX        100.0f
#define XAUDIO2FX_REVERB_DEFAULT_REFLECTIONS_DELAY  5
#define XAUDIO2FX_REVERB_DEFAULT_REVERB_DELAY       5
#define XAUDIO2FX_REVERB_DEFAULT_REAR_DELAY         5
#define XAUDIO2FX_REVERB_DEFAULT_POSITION           6
#define XAUDIO2FX_REVERB_DEFAULT_POSITION_MATRIX    27
#define XAUDIO2FX_REVERB_DEFAULT_EARLY_DIFFUSION    8
#define XAUDIO2FX_REVERB_DEFAULT_LATE_DIFFUSION     8
#define XAUDIO2FX_REVERB_DEFAULT_LOW_EQ_GAIN        8
#define XAUDIO2FX_REVERB_DEFAULT_LOW_EQ_CUTOFF      4
#define XAUDIO2FX_REVERB_DEFAULT_HIGH_EQ_GAIN       8
#define XAUDIO2FX_REVERB_DEFAULT_HIGH_EQ_CUTOFF     4
#define XAUDIO2FX_REVERB_DEFAULT_ROOM_FILTER_FREQ   5000.0f
#define XAUDIO2FX_REVERB_DEFAULT_ROOM_FILTER_MAIN   0.0f
#define XAUDIO2FX_REVERB_DEFAULT_ROOM_FILTER_HF     0.0f
#define XAUDIO2FX_REVERB_DEFAULT_REFLECTIONS_GAIN   0.0f
#define XAUDIO2FX_REVERB_DEFAULT_REVERB_GAIN        0.0f
#define XAUDIO2FX_REVERB_DEFAULT_DECAY_TIME         1.0f
#define XAUDIO2FX_REVERB_DEFAULT_DENSITY            100.0f
#define XAUDIO2FX_REVERB_DEFAULT_ROOM_SIZE          100.0f
#define XAUDIO2FX_REVERB_DEFAULT_DISABLE_LATE_FIELD FALSE

本篇主要是展示如何使用内置混响音频特效，具体实现代码如下：

#pragma once
#include "WaveFile.h"
#include "XAudio2.h"
#include <XAudio2fx.h>

class VoiceCallBack : public IXAudio2VoiceCallback
{
public:
	HANDLE hBufferEndEvent;
	VoiceCallBack() : hBufferEndEvent(CreateEvent(NULL, FALSE, FALSE, NULL)){}
	~VoiceCallBack(){ CloseHandle(hBufferEndEvent); }
	void OnStreamEnd() { /*SetEvent(hBufferEndEvent);*/ }
	void OnVoiceProcessingPassEnd() { }
	void OnVoiceProcessingPassStart(UINT32 SamplesRequired) {    }
	//Called when the voice has just finished playing an audio buffer.
	void OnBufferEnd(void * pBufferContext)    { SetEvent(hBufferEndEvent); }
	void OnBufferStart(void * pBufferContext) {    }
	void OnLoopEnd(void * pBufferContext) { /*SetEvent(hBufferEndEvent);*/ }
	void OnVoiceError(void * pBufferContext, HRESULT Error) { }
};

 int main(int argc, char *argv[])
 {
	 HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);;//com初始化
 	if (FAILED(hr))
 		return 0;
 
 	IXAudio2 *pEngine = NULL;
 	hr = XAudio2Create(&pEngine);//创建引擎
 	if (FAILED(hr))
 		return 0;
 
 	IXAudio2MasteringVoice *pMasterVoice = NULL;
 	hr = pEngine->CreateMasteringVoice(&pMasterVoice);//创建主声音，默认是输出当前扬声器
 	if (FAILED(hr))
 		return 0;
 
 	CWaveFile waveFile;
 	hr = waveFile.Open(L"F:\\桌面\\24bit-48khz.wav", NULL, WAVEFILE_READ);//加载文件
 	if (FAILED(hr))
 		return 0;
 
 	WAVEFORMATEX *waveFormat = waveFile.GetFormat();//获取文件格式
	VoiceCallBack callBack;
 	IXAudio2SourceVoice *pSourceVoice = NULL;
	hr = pEngine->CreateSourceVoice(&pSourceVoice, waveFormat, 0, 1.0f, &callBack);//创建源声音，用来提交数据
 	if (FAILED(hr))
 		return 0;

	IUnknown *pXAPO = NULL;
	hr = XAudio2CreateReverb(&pXAPO);//创建混响对象
	if (FAILED(hr))
		return 0;

	XAUDIO2_EFFECT_DESCRIPTOR descriptor;//效果描述，包含了一个XAPO的信息
	descriptor.InitialState = true;
	descriptor.OutputChannels = 2;
	descriptor.pEffect = pXAPO;

	XAUDIO2_EFFECT_CHAIN eChain;//效果链，包含了含有几个效果对象
	eChain.EffectCount = 1;
	eChain.pEffectDescriptors = &descriptor;

	hr = pSourceVoice->SetEffectChain(&eChain);//将效果链传递给voice
	if (FAILED(hr))
		return 0;
 
	pXAPO->Release();//传给voice后，voice接管此对象。防止外部对此对象修改，释放

	XAUDIO2FX_REVERB_PARAMETERS reverbParameters;//创建参数结构体对象
	reverbParameters.ReflectionsDelay = XAUDIO2FX_REVERB_DEFAULT_REFLECTIONS_DELAY;
	reverbParameters.ReverbDelay = XAUDIO2FX_REVERB_DEFAULT_REVERB_DELAY;
	reverbParameters.RearDelay = XAUDIO2FX_REVERB_DEFAULT_REAR_DELAY;
	reverbParameters.PositionLeft = XAUDIO2FX_REVERB_DEFAULT_POSITION;
	reverbParameters.PositionRight = XAUDIO2FX_REVERB_DEFAULT_POSITION;
	reverbParameters.PositionMatrixLeft = XAUDIO2FX_REVERB_DEFAULT_POSITION_MATRIX;
	reverbParameters.PositionMatrixRight = XAUDIO2FX_REVERB_DEFAULT_POSITION_MATRIX;
	reverbParameters.EarlyDiffusion = XAUDIO2FX_REVERB_DEFAULT_EARLY_DIFFUSION;
	reverbParameters.LateDiffusion = XAUDIO2FX_REVERB_DEFAULT_LATE_DIFFUSION;
	reverbParameters.LowEQGain = XAUDIO2FX_REVERB_DEFAULT_LOW_EQ_GAIN;
	reverbParameters.LowEQCutoff = XAUDIO2FX_REVERB_DEFAULT_LOW_EQ_CUTOFF;
	reverbParameters.HighEQGain = XAUDIO2FX_REVERB_DEFAULT_HIGH_EQ_GAIN;
	reverbParameters.HighEQCutoff = XAUDIO2FX_REVERB_DEFAULT_HIGH_EQ_CUTOFF;
	reverbParameters.RoomFilterFreq = XAUDIO2FX_REVERB_DEFAULT_ROOM_FILTER_FREQ;
	reverbParameters.RoomFilterMain = XAUDIO2FX_REVERB_DEFAULT_ROOM_FILTER_MAIN;
	reverbParameters.RoomFilterHF = XAUDIO2FX_REVERB_DEFAULT_ROOM_FILTER_HF;
	reverbParameters.ReflectionsGain = XAUDIO2FX_REVERB_DEFAULT_REFLECTIONS_GAIN;
	reverbParameters.ReverbGain = XAUDIO2FX_REVERB_DEFAULT_REVERB_GAIN;
	reverbParameters.DecayTime = XAUDIO2FX_REVERB_DEFAULT_DECAY_TIME;
	reverbParameters.Density = XAUDIO2FX_REVERB_DEFAULT_DENSITY;
	reverbParameters.RoomSize = XAUDIO2FX_REVERB_DEFAULT_ROOM_SIZE;
	reverbParameters.WetDryMix = XAUDIO2FX_REVERB_DEFAULT_WET_DRY_MIX;

	int effectIndex = 0;
	hr = pSourceVoice->SetEffectParameters(effectIndex, &reverbParameters, sizeof(reverbParameters));//将设置传递给voice
	if (FAILED(hr))
		return 0;

	hr = pSourceVoice->EnableEffect(effectIndex);//启动音效。禁止音效是DisableEffect(effectIndex);
	if (FAILED(hr))
		return 0;

 	DWORD size = waveFile.GetSize();//获取文件的大小
 	BYTE *pData = new BYTE[size];//申请内存空间，用于保存数据
 	hr = waveFile.Read(pData, size, &size);//读取文件内容
 	if (FAILED(hr))
 		return 0;
 
	XAUDIO2_BUFFER buffer = {0};//将读取的文件数据，赋值XAUDIO2_BUFFER
 	buffer.AudioBytes = size;
 	buffer.pAudioData = pData;
	//buffer.Flags = XAUDIO2_END_OF_STREAM;
 
 	hr = pSourceVoice->SubmitSourceBuffer(&buffer);//提交内存数据
 	if (FAILED(hr))
 		return 0;
 
 	hr = pSourceVoice->Start(0);//启动源声音
 	if (FAILED(hr))
 		return 0;
 
	XAUDIO2_VOICE_STATE state;
	while (pSourceVoice->GetState(&state), state.BuffersQueued > 0)//等待队列中的数据播放完成，退出线程
	{
		WaitForSingleObject(callBack.hBufferEndEvent, INFINITE);
	}
 
 	pMasterVoice->DestroyVoice();//释放资源
 	pSourceVoice->DestroyVoice();//释放资源
 	pEngine->Release();//释放资源
 	CoUninitialize();//释放资源

	delete []pData;//释放资源
	pData = NULL;

 	return 0;
 }

#include <XAudio2fx.h>才可以使用内置音效混响。

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本文地址：http://blog.csdn.net/u011417605/article/details/51178625

XAudio2学习之内置音效：混响

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原文地址：http://blog.csdn.net/u011417605/article/details/51178625