XAudio2学习之音频特效库XAPOFX
XAPOFX是一个继承自XAPO接口的音频效果集合，用于XAudio2。XAPOFX包含了几种效果以及一个通用的创建音效实例的机制。
XAPOFX中包含的效果如下表：
| Effect | Description | Parameter Structure | Parameter Constants | Requirements |
|---|---|---|---|---|
| FXECHO | An echo effect. | FXECHO_PARAMETERS | FXECHO Constants | Only supports FLOAT32 audio formats. |
| FXEQ | A four band equalizer. | FXEQ_PARAMETERS | FXEQ Constants | Only supports FLOAT32 audio formats. The sample rate must be between 22,000 Hz and 48,000 Hz. |
| FXMasteringLimiter | A volume limiter. | FXMASTERINGLIMITER_PARAMETERS | FXMASTERINGLIMIT Constants | Only supports FLOAT32 audio formats. |
| FXReverb | A simple reverb effect. XAudio2 also provides an effect implementing Princeton Digital Reverb that can be instantiated withXAudio2CreateReverb. |
FXREVERB_PARAMETERS | FXREVERB Constants | Only supports FLOAT32 audio formats. Also, it only supports mono input to mono output, and stereo input to stereo output. |
使用CreateFX接口作为通用机制来创建效果实例。此接口需要每个音效对应的CLSID来返回不同的效果实例。
HRESULT CreateFX(
CLSID clsid,
IUnknown **pEffect
)
每个XAudio2 voice拥有一条效果链，效果链中包含0或者多个音频效果。输送给voice的音频数据，在输出到目的voice之前，需要通过效果链中的每个效果。voice拥有每个效果的输出，输入给效果链中的下一个效果，直到效果链中没有剩余的效果为止。使用XAPOFX中的效果，步骤如下：
1.实例化一个效果；
2.填充XAUDIO2_EFFECT_DESCRIPTOR结构体；
3.填充XAUDIO2_EFFECT_CHAIN结构体；
4.将对象传递给XAudio2；
5.释放对象；
6.填充参数结构体；
7.将参数结构体传递给XAudio2.
XAPOFX相关的宏定义以及每个音效的CLSID:
// FX class IDs
class __declspec(uuid("F5E01117-D6C4-485A-A3F5-695196F3DBFA")) FXEQ;
class __declspec(uuid("C4137916-2BE1-46FD-8599-441536F49856")) FXMasteringLimiter;
class __declspec(uuid("7D9ACA56-CB68-4807-B632-B137352E8596")) FXReverb;
class __declspec(uuid("5039D740-F736-449A-84D3-A56202557B87")) FXEcho;
// EQ parameter bounds (inclusive), used with FXEQ:
#define FXEQ_MIN_FRAMERATE 22000
#define FXEQ_MAX_FRAMERATE 48000
#define FXEQ_MIN_FREQUENCY_CENTER 20.0f
#define FXEQ_MAX_FREQUENCY_CENTER 20000.0f
#define FXEQ_DEFAULT_FREQUENCY_CENTER_0 100.0f // band 0
#define FXEQ_DEFAULT_FREQUENCY_CENTER_1 800.0f // band 1
#define FXEQ_DEFAULT_FREQUENCY_CENTER_2 2000.0f // band 2
#define FXEQ_DEFAULT_FREQUENCY_CENTER_3 10000.0f // band 3
#define FXEQ_MIN_GAIN 0.126f // -18dB
#define FXEQ_MAX_GAIN 7.94f // +18dB
#define FXEQ_DEFAULT_GAIN 1.0f // 0dB change, all bands
#define FXEQ_MIN_BANDWIDTH 0.1f
#define FXEQ_MAX_BANDWIDTH 2.0f
#define FXEQ_DEFAULT_BANDWIDTH 1.0f // all bands
// Mastering limiter parameter bounds (inclusive), used with FXMasteringLimiter:
#define FXMASTERINGLIMITER_MIN_RELEASE 1
#define FXMASTERINGLIMITER_MAX_RELEASE 20
#define FXMASTERINGLIMITER_DEFAULT_RELEASE 6
#define FXMASTERINGLIMITER_MIN_LOUDNESS 1
#define FXMASTERINGLIMITER_MAX_LOUDNESS 1800
#define FXMASTERINGLIMITER_DEFAULT_LOUDNESS 1000
// Reverb parameter bounds (inclusive), used with FXReverb:
#define FXREVERB_MIN_DIFFUSION 0.0f
#define FXREVERB_MAX_DIFFUSION 1.0f
#define FXREVERB_DEFAULT_DIFFUSION 0.9f
#define FXREVERB_MIN_ROOMSIZE 0.0001f
#define FXREVERB_MAX_ROOMSIZE 1.0f
#define FXREVERB_DEFAULT_ROOMSIZE 0.6f
// Echo initialization data/parameter bounds (inclusive), used with FXEcho:
#define FXECHO_MIN_WETDRYMIX 0.0f
#define FXECHO_MAX_WETDRYMIX 1.0f
#define FXECHO_DEFAULT_WETDRYMIX 0.5f
#define FXECHO_MIN_FEEDBACK 0.0f
#define FXECHO_MAX_FEEDBACK 1.0f
#define FXECHO_DEFAULT_FEEDBACK 0.5f
#define FXECHO_MIN_DELAY 1.0f
#define FXECHO_MAX_DELAY 2000.0f
#define FXECHO_DEFAULT_DELAY 500.0f
每个音效对应的参数结构体如下：
// EQ parameters (4 bands), used with IXAPOParameters::SetParameters:
// The EQ supports only FLOAT32 audio foramts.
// The framerate must be within [22000, 48000] Hz.
typedef struct FXEQ_PARAMETERS {
float FrequencyCenter0; // center frequency in Hz, band 0
float Gain0; // boost/cut
float Bandwidth0; // bandwidth, region of EQ is center frequency +/- bandwidth/2
float FrequencyCenter1; // band 1
float Gain1;
float Bandwidth1;
float FrequencyCenter2; // band 2
float Gain2;
float Bandwidth2;
float FrequencyCenter3; // band 3
float Gain3;
float Bandwidth3;
} FXEQ_PARAMETERS;
// Mastering limiter parameters, used with IXAPOParameters::SetParameters:
// The mastering limiter supports only FLOAT32 audio formats.
typedef struct FXMASTERINGLIMITER_PARAMETERS {
UINT32 Release; // release time (tuning factor with no specific units)
UINT32 Loudness; // loudness target (threshold)
} FXMASTERINGLIMITER_PARAMETERS;
// Reverb parameters, used with IXAPOParameters::SetParameters:
// The reverb supports only FLOAT32 audio formats with the following
// channel configurations:
// Input: Mono Output: Mono
// Input: Stereo Output: Stereo
typedef struct FXREVERB_PARAMETERS {
float Diffusion; // diffusion
float RoomSize; // room size
} FXREVERB_PARAMETERS;
// Echo initialization data, used with CreateFX:
// Use of this structure is optional, the default MaxDelay is FXECHO_DEFAULT_DELAY.
typedef struct FXECHO_INITDATA {
float MaxDelay; // maximum delay (all channels) in milliseconds, must be within [FXECHO_MIN_DELAY, FXECHO_MAX_DELAY]
} FXECHO_INITDATA;
// Echo parameters, used with IXAPOParameters::SetParameters:
// The echo supports only FLOAT32 audio formats.
typedef struct FXECHO_PARAMETERS {
float WetDryMix; // ratio of wet (processed) signal to dry (original) signal
float Feedback; // amount of output fed back into input
float Delay; // delay (all channels) in milliseconds, must be within [FXECHO_MIN_DELAY, FXECHO_PARAMETERS.MaxDelay]
} FXECHO_PARAMETERS;
下面是如何使用XAPOFX库中音频效果的实例，使用方式类似于XAudio2内置音效：
#pragma once
#include "WaveFile.h"
#include "XAudio2.h"
#include <xapofx.h>
#pragma comment(lib,"XAPOFX.lib")
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;
hr = CreateFX(__uuidof(FXReverb), &pXAPO);//创建FXReverb特效。还有另外三个：FXEQ;FXMasteringLimiter;FXEcho。
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
FXREVERB_PARAMETERS XAPOParameters;
XAPOParameters.Diffusion = FXREVERB_DEFAULT_DIFFUSION;
XAPOParameters.RoomSize = FXREVERB_DEFAULT_ROOMSIZE;
int effectIndex = 0;
hr = pSourceVoice->SetEffectParameters(effectIndex, &XAPOParameters, sizeof(XAPOParameters));//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;
}
注意，需要包含
#include <xapofx.h> #pragma comment(lib,"XAPOFX.lib")才可以使用XAPOFX特效。
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