C++编程：XAudio2_API应用示例.docx

C+编程：XAudio2 API应用示例作者:LuoJun 声明:此文档未引用任何书籍期刊，无版权问题，可随意转载更新日期:2012/8/31XAudio2是一个跨平台的API，在Xbox 360及Windows中得到支持。在Xbox 360上， XAudio2作为一个静态库编译到游戏可执行文件中。在Windows上，XAudio2提供一个动态链接库（DLL）。以下例子只使用了其中的一部分功能，并不全面。详情请看微软技术页的XAudio2编程相关(英文)。使用XAudio2来播放未压缩的PCM音频数据的过程并不复杂，主要有以下几个步骤：1. 建立XAudio2 引擎使用XAudio2Create函数，该函数的功能是创建一个XAudio2对象(IXAudio2接口)。原型：HRESULT XAudio2Create(IXAudio2 *ppXAudio2,/这里返回XAudio2对象的指针UINT32 Flags,/此处必须为0 XAUDIO2_PROCESSOR XAudio2Processor/指定所用CPU,默认:XAUDIO2_DEFAULT_PROCESSOR);示例：XAudio2Create( &pXAudio2, 0, XAUDIO2_DEFAULT_PROCESSOR );2. 使用第1步建立的引擎建立MasteringVoice使用IXAudio2成员函数CreateMasteringVoice，该函数功能是创建并设置一个MasteringVoice原型：HRESULT CreateMasteringVoice(IXAudio2MasteringVoice *ppMasteringVoice,/这里返回MasteringVoice对象指针UINT32 InputChannels = XAUDIO2_DEFAULT_CHANNELS,/设置声道数，可选UINT32 InputSampleRate = XAUDIO2_DEFAULT_SAMPLERATE, /设置采样率，可选UINT32 Flags = 0,/必须是0，可选LPCWSTR szDeviceId = NULL, /设备，可选，NULL代表全局默认输出设备const XAUDIO2_EFFECT_CHAIN *pEffectChain = NULL, /音效，可选AUDIO_STREAM_CATEGORY StreamCategory = AudioCategory_GameEffects/流类型，可选);示例：pXAudio2-CreateMasteringVoice(&pMasterVoice);3. 使用第一步建立的引擎建立SourceVoice(或SubmixVoice，以下按SourceVoice举例)使用IXAudio2成员函数CreateSourceVoice，该函数功能是创建并设置一个SourceVoice原型：HRESULT CreateSourceVoice(IXAudio2SourceVoice *ppSourceVoice, /这里返回IXAudio2SourceVoice对象指针const WAVEFORMATEX *pSourceFormat, /PCM音频格式（下面讲到）UINT32 Flags = 0,/SourceVoide工作方式，可选float MaxFrequencyRatio = XAUDIO2_DEFAULT_FREQ_RATIO,/声调，可选，默认为1IXAudio2VoiceCallback *pCallback = NULL,/回调类指针，可选const XAUDIO2_VOICE_SENDS *pSendList = NULL,/目标格式设置，可选const XAUDIO2_EFFECT_CHAIN *pEffectChain = NULL/音效设置，可选);示例：pXAudio2-CreateSourceVoice(&pSourceVoice,&format,0,XAUDIO2_DEFAULT_FREQ_RATIO,NULL,NULL,NULL);其中format这样设置：（位数为bits，声道数为channels，采样率为hz）WAVEFORMATEX format;format.wFormatTag = WAVE_FORMAT_PCM;/PCM格式format.wBitsPerSample = bits;/位数format.nChannels = channels;/声道数format.nSamplesPerSec = hz;/采样率format.nBlockAlign = bits*channels/8;/数据块调整format.nAvgBytesPerSec = format.nBlockAlign*hz;/平均传输速率format.cbSize = 0;/附加信息4. 呈交音频数据使用IXAudio2SourceVoice的成员函数SubmitSourceBuffer，该函数功能是呈交一个XAUDIO2_BUFFER原型：HRESULT SubmitSourceBuffer(const XAUDIO2_BUFFER *pBuffer,/ 结构体XAUDIO2_BUFFER的指针（下面讲到）const XAUDIO2_BUFFER_WMA *pBufferWMA = NULL/wma格式Buffer的指针,可选,默认NULL);示例：pSourceVoice-SubmitSourceBuffer(&XAudio2Buffer,NULL);其中XAudio2Buffer这样设置：XAUDIO2_BUFFER XAudio2Buffer;XAudio2Buffer.Flags = 0;/可以设为0或XAUDIO2_END_OF_STREAM，当设为后者时，将使XAudio2播放完该数据块后自动停止，不再播放下一个数据块XAudio2Buffer.AudioBytes = BufferSize;/ 音频数据的长度，按字节算XAudio2Buffer.pAudioData = pBuffer;/具体音频数据的地址，unsigned char pBufferXAudio2Buffer.PlayBegin = 0;/起始播放地址XAudio2Buffer.PlayLength = 0;/播放长度，0为整数据块XAudio2Buffer.LoopBegin = 0;/循环起始位置XAudio2Buffer.LoopLength = 0;/循环长度，按字节算XAudio2Buffer.LoopCount = 0;/循环次数，0为不循环，255为无限循环XAudio2Buffer.pContext = NULL;/这里的pContext用来标识该数据块，供回调用，可以是NULL5. 继续呈交数据和播放数据：播放呈交的数据使用IXAudio2SourceVoice的成员函数Start，该函数功能是开始播放。原型：HRESULT Start(UINT32 Flags,/必须是0UINT32 OperationSet = XAUDIO2_COMMIT_NOW/使用XAUDIO2_COMMIT_NOW将立即生效，使用XAUDIO2_COMMIT_ALL将挂起，等待其它的数值的OperationSet的处理完);示例：pSourceVoice-Start(0, XAUDIO2_COMMIT_NOW);第5步做完之后，XAudio2将一块接一块地播放呈交的数据块。我们只需不断重复第四步，就能不断地播放音频数据了。需要注意的是，在XAudio2播放完某个XAudio2Buffer之前，该XAudio2Buffer以及XAudio2Buffer.pAudioData所指向的内存不能被修改或删除，否则将发生错误。但是某个XAudio2Buffer一旦被播放完，就能被修改了。为此，我们可以创建一个数组XAUDIO2_BUFFER 来循环呈交和更新数据。那怎么知道XAudio2到底播放了几个XAudio2Buffer呢，可以使用IXAudio2SourceVoice的成员函数GetState原型：GetState(XAUDIO2_VOICE_STATE *pVoiceState,/ 这里返回XAUDIO2_VOICE_STATE结构体指针optional UINT32 Flags/获取方式,可选,默认0.设为XAUDIO2_VOICE_NOSAMPLESPLAYED将只获取挂起(包括正在播放)的XAudio2Buffer数量，速度较快。注意：DirectX SDK版本没有此参数);XAUDIO2_VOICE_STATE包含三个成员：void * pCurrentBufferContext/对应XAUDIO2_BUFFER中的pContextUINT32 BuffersQueued/挂起(包括正在播放)的XAudio2Buffer数量UINT64 SamplesPlayed/已播放的样本数示例： pSourceVoice-GetState(&state);6. 暂停和停止播放暂停播放使用IXAudio2SourceVoice的成员函数：Stop原型：HRESULT Stop(UINT32 Flags,/ 设为0或XAUDIO2_PLAY_TAILS，后者代表等待音效放完UINT32 OperationSet = XAUDIO2_COMMIT_NOW/ XAUDIO2_COMMIT_NOW立即生效);如果设定XAUDIO2_PLAY_TAILS，应在音效输出完成后设定0,再Stop一次。暂停后再次调用Start将在暂停的位置开始播放。如果要完全停止，还需要使用IXAudio2SourceVoice的成员函数FlushSourceBuffers，该函数功能是清除挂起的XAudio2Buffer队列。原型：HRESULT FlushSourceBuffers();说明：该函数使用后要到XAudio2播放完一个XAudio2Buffer才生效，建议在回调中使用。使用该函数后，XAudio2Buffer队列计数将置07. IXAudio2SourceVoice的其他功能：设置声调使用SetFrequencyRatio函数原型：HRESULT SetFrequencyRatio(float Ratio,/1.0为正常声调，1.0为高声调快放，1.0为低声调慢放UINT32 OperationSet = XAUDIO2_COMMIT_NOW);IXAudio2SourceVoice继承自IXAudio2Voice，所以还有许多IXAudio2Voice的功能，比如设置音量用SetVolume等。注意：以上IXAudio2SourceVoice的成员函数中， Stop、GetState、 FlushSourceBuffers可以在回调中使用释放相关实例的顺序与创建他们的顺序相反。需要包含头文件Xaudio2.h和Objbase.h以及链接ole32.lib(而不是Microsoft网站上的Xaudio2.lib)下面给出我写的一个Speaker类供大家参考，该类使用XAudio2来播放PCM数据，在Win7x64系统中使用VS2010、DirectX SDK按x64、/clr(Speaker中没有使用托管类)编译测试通过其公开成员函数ReadData采用阻塞的方法来读取音频数据，一旦塞满缓冲区将自动开始播放，播放多少就读取多少，SetFormat设置PCM音频格式(不设置的话，默认是16位、2声道、44100采样率)。SetBufferSize设置缓冲块数和每块大小(不设置的话，默认是4块，每块40KB)#include #include #include Objbase.h#pragma comment(lib,Ole32.lib)#define DEF_MaxBufferCount4#define DEF_StreamingBufferSize40960class VoiceCallBack;class Speaker;class VoiceCallBack:public IXAudio2VoiceCallback/回调类public:HANDLE hBufferEndEvent; VoiceCallBack():hBufferEndEvent(CreateEvent(NULL,FALSE,FALSE,NULL)count =lastcontext = currentcontext= 0; VoiceCallBack()CloseHandle(hBufferEndEvent); Speaker *speaker; XAUDIO2_VOICE_STATE state;public:int count; int lastcontext; int currentcontext; /播放一个数据块前后触发事件 void OnBufferEnd(void *pBufferContext); /不需要的方法只保留声明 void OnBufferStart(void *pBufferContext) void OnVoiceProcessingPassEnd() void OnVoiceProcessingPassStart(UINT32 SamplesRequired) void OnStreamEnd() void OnLoopEnd(void *pBufferContext) void OnVoiceError(void *pBufferContext,HRESULT Error);class Speakerpublic:/XAudio2数据IXAudio2* pXAudio2;/XAudio2引擎IXAudio2MasteringVoice* pMasterVoice;/MsterVoiceVoiceCallBack voiceCallBack;/回调处理XAUDIO2_BUFFER *pXAudio2Buffer;/封装的用来呈交的音频缓冲数据块WAVEFORMATEX WaveFormat;/音频格式IXAudio2SourceVoice *pSourceVoice;/源音处理接口int MaxBufferCount;/最大缓冲数据块数int StreamingBufferSize;/缓冲数据块大小unsigned char *ppAudioData;/音频缓冲数据bool IsPlaying;/是否在播放HRESULT State;/状态，0为正常，0为信息或警告const wchar_t *pState;/状态内容详细描述/跟外部读取交换数据int ReadingBufferNumber;/正在读取的Bufferint WritingBufferNumber;/正在写入的Bufferint UnReadBufferCount;/未呈交Buffer数量int UnProcessedBufferCount;/呈交但未处理的Buffer数量int WritingPosition;/当前块准备写入位置/控制函数部分public:Speaker();/默认构造函数public:Speaker();/析构函数private:void reset();/重置交换数据参数private:HRESULT SetState(HRESULT state);/设置简单的状态信息public:void StopPlaying();/停止播放public:void Pause();/暂停public:void StartPlaying();/开始播放public:void SetFormat(short bits,short channels,int hz);/更改PCM格式public:void SetBufferSize(int MaxBufferCount,int StreamingBufferSize);/分配音频数据缓冲区public:static XAUDIO2_BUFFER MakeXAudio2Buffer(const BYTE *pBuffer,int BufferSize);/生成XAudio2缓冲区public:static WAVEFORMATEX MakePCMSourceFormat(short bits,short channels,int hz);/生成PCM格式信息public:void ReadData(unsigned char *pBuffer,int length);/从pBuffer指向的内存复制length字节的数据到缓冲区,不复制完不返回public:int ReadDataFrom(unsigned char *pBuffer,int length);/从pBuffer指向的内存复制length字节的数据,立即返回实际复制的数据字节数;void VoiceCallBack:OnBufferEnd(void *pBufferContext)if(pBufferContext = NULL)speaker-pSourceVoice-GetState(&state);speaker-UnProcessedBufferCount=state.BuffersQueued;elsecurrentcontext = *(int *) pBufferContext)+1;if(currentcontext lastcontext)count += currentcontext - lastcontext;else if(currentcontext MaxBufferCount + currentcontext - lastcontext;lastcontext = currentcontext;speaker-UnProcessedBufferCount -= count;count = 0;while(speaker-UnReadBufferCount & ( speaker-UnReadBufferCount1 | speaker-UnProcessedBufferCount+speaker-UnReadBufferCount+1 MaxBufferCount)/提交，但保留一块缓冲区，以免冲突speaker-pSourceVoice-SubmitSourceBuffer(&speaker-pXAudio2Bufferspeaker-ReadingBufferNumber,NULL);speaker-ReadingBufferNumber = (1 + speaker-ReadingBufferNumber) % speaker-MaxBufferCount;speaker-UnProcessedBufferCount+;speaker-UnReadBufferCount -;SetEvent(hBufferEndEvent); Speaker:Speaker()/初始化IsPlaying = false;MaxBufferCount = 0;StreamingBufferSize = 0;voiceCallBack.speaker = this;reset();/建立引擎if(FAILED(SetState(XAudio2Create( &pXAudio2, 0, XAUDIO2_DEFAULT_PROCESSOR )goto END;/建立MasteringVoiceif(FAILED(SetState(pXAudio2-CreateMasteringVoice(&pMasterVoice)goto END;/分配缓冲内存并设置XAudio2BufferSetBufferSize(DEF_MaxBufferCount,DEF_StreamingBufferSize);/设置默认缓冲/设置pcm格式WaveFormat = Speaker:MakePCMSourceFormat(16,2,44100);/建立SourceVoiceSetState(pXAudio2-CreateSourceVoice(&this-pSourceVoice,&this-WaveFormat,0,XAUDIO2_DEFAULT_FREQ_RATIO,&this-voiceCallBack,NULL,NULL);END:;Speaker:Speaker()SetBufferSize(0,0);/停止播放并释放缓冲区if(pSourceVoice != NULL)pSourceVoice-DestroyVoice();if(pMasterVoice != NULL)pMasterVoice-DestroyVoice();if(pXAudio2 != NULL)pXAudio2-StopEngine();void Speaker:reset()SetState(0);ReadingBufferNumber = 0;UnReadBufferCount = 0;UnProcessedBufferCount = 0;WritingBufferNumber = 0;WritingPosition = 0;voiceCallBack.count = 0;voiceCallBack.lastcontext = 0;void Speaker:StopPlaying()if(pSourceVoice = NULL)return;XAUDIO2_VOICE_STATE state;if(IsPlaying)IsPlaying = false;pSourceVoice-GetState(&state);while(state.BuffersQueued)if(FAILED(SetState(pSourceVoice-Stop(0,XAUDIO2_COMMIT_NOW)return;if(FAILED(SetState(pSourceVoice-FlushSourceBuffers()return;Sleep(1);pSourceVoice-GetState(&state);reset();void Speaker:Pause()if(pSourceVoice = NULL)return;if(IsPlaying)SetState(pSourceVoice-Stop(0,XAUDIO2_COMMIT_NOW);if(FAILED(State)return;IsPlaying = false;void Speaker:StartPlaying()SetState(pSourceVoice-Start(0,XAUDIO2_COMMIT_NOW);if(FAILED(State)return;this-IsPlaying = true;void Speaker:SetFormat(short bits,short channels,int hz)if(WaveFormat.wBitsPerSample = bits & WaveFormat.nChannels = channels & WaveFormat.nSamplesPerSec = hz)return;StopPlaying();if(pSourceVoice)pSourceVoice-DestroyVoice();pSourceVoice = NULL;WaveFormat = MakePCMSourceFormat(bits,channels,hz);if(FAILED(SetState(pXAudio2-CreateSourceVoice(&pSourceVoice,&WaveFormat,0,XAUDIO2_DEFAULT_FREQ_RATIO,&this-voiceCallBack,NULL,NULL)pSourceVoice = NULL;void Speaker:SetBufferSize(int MaxBufferCount,int StreamingBufferSize)if (this-MaxBufferCount!=MaxBufferCount | this-StreamingBufferSize!=StreamingBufferSize)this-StopPlaying();for(int i=0;iMaxBufferCount;+i)if(this-StreamingBufferSize)/删除块delete this-ppAudioDatai;if(this-pXAudio2Bufferi.pContext)delete this-pXAudio2Bufferi.pContext;if(this-MaxBufferCount)/删除所有delete this-ppAudioData;delete this-pXAudio2Buffer;this-MaxBufferCount=MaxBufferCount;/赋值this-StreamingBufferSize=StreamingBufferSize;voiceCallBack.lastcontext = 0;if(MaxBufferCount)/创建reset();this-ppAudioData = new unsigned char *MaxBufferCount;this-pXAudio2Buffer = new XAUDIO2_BUFFERMaxBufferCount;if (StreamingBufferSize)this-pXAudio2Buffer = new XAUDIO2_BUFFERMaxBufferCount;for(int i=0;ippAudioDatai = new unsigned charStreamingBufferSize;this-pXAudio2Bufferi = Speaker:MakeXAudio2Buffer(ppAudioDatai,StreamingBufferSize);*(int*)this-pXAudio2Bufferi.pContext) = i;XAUDIO2_BUFFER Speaker:MakeXAudio2Buffer(const BYTE *pBuffer,int BufferSize)XAUDIO2_BUFFER XAudio2Buffer;XAudio2Buffer.AudioBytes = BufferSize;XAudio2Buffer.Flags = 0;XAudio2Buffer.LoopBegin = 0;XAudio2Buffer.LoopCount = 0;XAudio2Buffer.LoopLength = 0;XAudio2Buffer.pAudioData = pBuffer;XAudio2Buffer.pContext = (void*)new int1;XAudio2Buffer.PlayBegin = 0;XAudio2Buffer.PlayLength = 0;return XAudio2Buffer;WAVEFORMATEX Speaker:MakePCMSourceFormat(short bits,short channels,int hz)WAVEFORMATEX format;format.wFormatTag = WAVE_FORMAT_PCM;/PCM格式format.wBitsPerSample = bits;/位数format.nChannels = channels;/声道数format.nSamplesPerSec = hz;/采样率format.nBlockAlign = bits*channels/8;/数据块调整format.nAvgBytesPerSec = format.nBlockAlign*hz;/平均传输速率format.cbSize = 0;/附加信息return format;void Speaker:ReadData(unsigned char *pBuffer,int length)int i=0;while(lengthi)/不读完不退出循环while(UnProcessedBufferCount + UnReadBufferCount = MaxBufferCount)if(!IsPlaying)StartPlaying();Sleep(0);continue;voiceCallBack.OnBufferEnd(NULL);Sleep(10);if(StreamingBufferSize length-i+WritingPosition)while(ippAudioDataWritingBufferNumberWritingPosition = pBufferi;+Wri