XAudio2学习之混音
XAudio2不仅能够进行採样率转换。还能够进行混音。所谓混音就是将多路音频混合成一路进行输出。混音主要是IXAudio2SubmixVoice进行此项功能。
数据由IXAudio2SourceVoice提交后。流向IXAudio2SubmixVoice进行採样率转换（假设须要的话），而且进行音频混合，最后形成一路採样率和IXAudio2MasteringVoice一致的音频流，由IXAudio2MasteringVoice输出到音频输出设备。
混音主要步骤：
1.初始化COM组件。
2.指定特定格式创建Mastering Voice:2通道/48K。32位深。
3.创建一个IXAudio2SubmixVoice对象，格式和mastering voice一致：作用是混合两路音频为一路，并输出到mastering voice。
4.打开多个文件来提供多路音频数据：这里使用两个文件。
5.针对每一个文件创建IXAudio2SourceVoice对象，格式为每一个文件的格式。
6.针对每一个IXAudio2SourceVoice创建IXAudio2SubmixVoice对象，并分别设置输入格式为每一个文件相应的格式，分别设置为IXAudio2SourceVoice对象的输出voice，并分别指定IXAudio2SubmixVoice对象的输出voice为第三步创建的用来混音的IXAudio2SubmixVoice对象。
主要用来採样率转换，将採样率由文件提供的採样率转为和Mastering Voice一致的採样率。
7.分配内存，分别读取文件数据。并制定到XAUDIO2_BUFFER。
8.分别调用SubmitSourceBuffer将数据提交。
9.分别调用Start来启动Source Voice。
10.等待播放完毕。
11.释放对象和内存数据。
主要实现代码例如以下：WaveFile.h/WaveFile.cpp请到前面文章中寻找地址自行下载。
#pragma once
#include "WaveFile.h"
#include "XAudio2.h"
class VoiceCallback : public IXAudio2VoiceCallback
{
public:
HANDLE hBufferEndEvent;
VoiceCallback() : hBufferEndEvent(CreateEvent(NULL, FALSE, FALSE, NULL)){}
~VoiceCallback(){ CloseHandle(hBufferEndEvent); }
//Called when the voice has just finished playing a contiguous audio stream.
void OnStreamEnd() { SetEvent(hBufferEndEvent); }
//Unused methods are stubs
void OnVoiceProcessingPassEnd() { }
void OnVoiceProcessingPassStart(UINT32 SamplesRequired) { }
void OnBufferEnd(void * pBufferContext) { }
void OnBufferStart(void * pBufferContext) { }
void OnLoopEnd(void * pBufferContext) { }
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;
WAVEFORMATEX waveFormatex;//设置主声音的格式
waveFormatex.nChannels = 2;
waveFormatex.nSamplesPerSec = 48000;
waveFormatex.wBitsPerSample = 32;
waveFormatex.nAvgBytesPerSec = 384000;
waveFormatex.nBlockAlign = 8;
waveFormatex.wFormatTag = WAVE_FORMAT_PCM;
IXAudio2MasteringVoice *pMasterVoice = NULL;
hr = pEngine->CreateMasteringVoice(&pMasterVoice,waveFormatex.nChannels,waveFormatex.nSamplesPerSec);//创建主声音。默认是输出当前扬声器
if (FAILED(hr))
return 0;
XAUDIO2_SEND_DESCRIPTOR pSend;
pSend.pOutputVoice = pMasterVoice;//指定输出为mastering voice
pSend.Flags = XAUDIO2_SEND_USEFILTER;
XAUDIO2_VOICE_SENDS pSendList;
pSendList.pSends = &pSend;
pSendList.SendCount = 1;
IXAudio2SubmixVoice *pSubmixVoice = NULL;
hr = pEngine->CreateSubmixVoice(&pSubmixVoice, waveFormatex.nChannels, waveFormatex.nSamplesPerSec, 0, 0, &pSendList);//指定输出为mastering voice,作用：混音，将两路音频数据混为一路并输出到mastering voice
if (FAILED(hr))
return 0;
CWaveFile waveFile1;
hr = waveFile1.Open(L"C:\Users\xdd\Desktop\时间都去哪儿了.wav", NULL, WAVEFILE_READ);//载入文件1
if (FAILED(hr))
return 0;
CWaveFile waveFile2;
hr = waveFile2.Open(L"C:\Users\xdd\Desktop\1KHz-stero.wav", NULL, WAVEFILE_READ);//载入文件2
if (FAILED(hr))
return 0;
WAVEFORMATEX *waveFormat1 = waveFile1.GetFormat();//获取文件格式1
WAVEFORMATEX *waveFormat2 = waveFile2.GetFormat();//获取文件格式2
pSend.pOutputVoice = pSubmixVoice;//指定输出为SubmixVoice
IXAudio2SubmixVoice *pSubmixVoice1 = NULL;
hr = pEngine->CreateSubmixVoice(&pSubmixVoice1, waveFormat1->nChannels, waveFormat1->nSamplesPerSec, 0, 0, &pSendList);//指定输出为pSubmixVoice,作用：对文件1的音频数据进行重採样为mastering voice的採样率
if (FAILED(hr))
return 0;
IXAudio2SubmixVoice *pSubmixVoice2 = NULL;
hr = pEngine->CreateSubmixVoice(&pSubmixVoice2, waveFormat2->nChannels, waveFormat2->nSamplesPerSec, 0, 0, &pSendList);//指定输出为pSubmixVoice,作用：对文件2的音频数据进行重採样为mastering voice的採样率
if (FAILED(hr))
return 0;
pSend.pOutputVoice = pSubmixVoice1;//指定输出为pSubmixVoice1
VoiceCallback voiceCallBack1;
IXAudio2SourceVoice *pSourceVoice1 = NULL;
hr = pEngine->CreateSourceVoice(&pSourceVoice1, waveFormat1, 0, 1.0f, &voiceCallBack1,&pSendList);//创建源声音。用来提交数据.指定输出为SubmixVoice1
if (FAILED(hr))
return 0;
pSend.pOutputVoice = pSubmixVoice2;//指定输出为pSubmixVoice2
VoiceCallback voiceCallBack2;
IXAudio2SourceVoice *pSourceVoice2 = NULL;
hr = pEngine->CreateSourceVoice(&pSourceVoice2, waveFormat2, 0, 1.0f, &voiceCallBack2, &pSendList);//创建源声音，用来提交数据.指定输出为SubmixVoice2
if (FAILED(hr))
return 0;
DWORD size1 = waveFile1.GetSize();//获取文件的大小
BYTE *pData1 = new BYTE[size1];//申请内存空间，用于保存数据
hr = waveFile1.Read(pData1, size1, &size1);//读取文件内容
if (FAILED(hr))
return 0;
DWORD size2 = waveFile2.GetSize();//获取文件的大小
BYTE *pData2 = new BYTE[size2];//申请内存空间，用于保存数据
hr = waveFile2.Read(pData2, size2, &size2);//读取文件内容
if (FAILED(hr))
return 0;
XAUDIO2_BUFFER buffer1 = {0};//将读取的文件数据，赋值XAUDIO2_BUFFER
buffer1.AudioBytes = size1;
buffer1.pAudioData = pData1;
buffer1.Flags = XAUDIO2_END_OF_STREAM;
XAUDIO2_BUFFER buffer2 = { 0 };//将读取的文件数据。赋值XAUDIO2_BUFFER
buffer2.AudioBytes = size2;
buffer2.pAudioData = pData2;
buffer2.Flags = XAUDIO2_END_OF_STREAM;
hr = pSourceVoice1->SubmitSourceBuffer(&buffer1);//提交内存数据
if (FAILED(hr))
return 0;
hr = pSourceVoice2->SubmitSourceBuffer(&buffer2);//提交内存数据
if (FAILED(hr))
return 0;
hr = pSourceVoice1->Start(0);//启动源声音
if (FAILED(hr))
return 0;
hr = pSourceVoice2->Start(0);//启动源声音
if (FAILED(hr))
return 0;
XAUDIO2_VOICE_STATE state;
pSourceVoice1->GetState(&state);//获取状态
while (state.BuffersQueued)
{
WaitForSingleObject(voiceCallBack1.hBufferEndEvent, INFINITE);
pSourceVoice2->GetState(&state);
WaitForSingleObject(voiceCallBack2.hBufferEndEvent, INFINITE);
}
pMasterVoice->DestroyVoice();//释放资源
pSubmixVoice->DestroyVoice();//
pSubmixVoice1->DestroyVoice();//
pSubmixVoice2->DestroyVoice();//
pSourceVoice1->DestroyVoice();//释放资源
pSourceVoice2->DestroyVoice();//释放资源
pEngine->Release();//释放资源
CoUninitialize();//释放资源
delete []pData1;//释放资源
pData1 = NULL;
delete[]pData2;//释放资源
pData2 = NULL;
return 0;
}
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本文地址：http://blog.csdn.net/u011417605/article/details/51051039