Directshow的音频捕获和回放测试(2)
CMemPlayStream::CMemPlayStream(HRESULT *phr,
CMemPlay *pParent,
LPCWSTR pPinName) :
CSourceStream(NAME("Memory Play"),phr, pParent, pPinName),
m_iDefaultRepeatTime(20)
{
ASSERT(phr);
CAutoLock cAutoLock(&m_cSharedState);
for(int i=0; i<1024; i++)
{
m_DataList[i] = NULL;
m_SampleSize[i] = 0;
m_StartTimeList[i] = 0;
m_StopTimeList[i] = 0;
}
m_SampleCount = 0;
m_SampleReaded = 0;
FILE *fp = NULL;
fp = fopen("c://audiodata", "rb");
if(fp == NULL) return;
BYTE *pBuffer = NULL;
long size = 0;
REFERENCE_TIME StartTime;
REFERENCE_TIME StopTime;
while(!feof(fp))
{
fread(&size, sizeof(long), 1, fp);
if(size <=0) break;
fread(&StartTime, sizeof(REFERENCE_TIME), 1, fp);
fread(&StopTime, sizeof(REFERENCE_TIME), 1, fp);
pBuffer = new BYTE[size];
fread(pBuffer, sizeof(BYTE), size, fp);
m_SampleSize[m_SampleCount] = size;
m_DataList[m_SampleCount] = pBuffer;
m_StartTimeList[m_SampleCount] = StartTime;
m_StopTimeList[m_SampleCount] = StopTime;
m_SampleCount ++;
pBuffer = NULL;
size = 0;
}
fclose(fp);
} // (Constructor)
CMemPlayStream::~CMemPlayStream()
{
CAutoLock cAutoLock(&m_cSharedState);
for(int i=0; i
delete[] m_DataList[i];
m_DataList[i] = NULL;
m_SampleSize[i] = 0;
m_StartTimeList[i] = 0;
m_StopTimeList[i] = 0;
}
} // (Destructor)
HRESULT CMemPlayStream::FillBuffer(IMediaSample *pms)
{
CheckPointer(pms,E_POINTER);
BYTE *pData;
long lDataLen;
pms->GetPointer(&pData);
lDataLen = pms->GetSize();
ZeroMemory(pData, lDataLen);
{
CAutoLock cAutoLockShared(&m_cSharedState);
long lBytesFilled = 0;
lBytesFilled = (m_SampleSize[m_SampleReaded] < lDataLen) ?
m_SampleSize[m_SampleReaded] :
lDataLen;
memcpy(pData, m_DataList[m_SampleReaded], lBytesFilled);
CRefTime rtStart = m_rtSampleTime;
m_rtSampleTime += (LONG)(m_StopTimeList[m_SampleReaded] - m_StartTimeList[m_SampleReaded]);
if(m_SampleReaded ++ >= m_SampleCount) return S_FALSE;
pms->SetTime((REFERENCE_TIME *) &rtStart,(REFERENCE_TIME *) &m_rtSampleTime);
}
pms->SetSyncPoint(TRUE);
return NOERROR;
} // FillBuffer
HRESULT CMemPlayStream::GetMediaType(CMediaType *pmt)
{
CheckPointer(pmt,E_POINTER);
CAutoLock cAutoLock(m_pFilter->pStateLock());
WAVEFORMATEX *pwi = (WAVEFORMATEX *) pmt->AllocFormatBuffer(sizeof(WAVEFORMATEX));
if(NULL == pwi)
return(E_OUTOFMEMORY);
ZeroMemory(pwi, sizeof(WAVEFORMATEX));
int nFrequency = 44100;
int nChannels = 2;
int nBytesPerSample = 2;
long lBytesPerSecond = (long) (nBytesPerSample * nFrequency * nChannels);
long lBufferSize = (long) ((float) lBytesPerSecond);
pwi->wFormatTag = WAVE_FORMAT_PCM;
pwi->nChannels = (unsigned short)nChannels;
pwi->nSamplesPerSec = nFrequency;
pwi->nAvgBytesPerSec = lBytesPerSecond;
pwi->wBitsPerSample = (WORD) (nBytesPerSample * 8);
pwi->nBlockAlign = (WORD) (nBytesPerSample * nChannels);
pmt->SetType(&MEDIATYPE_Audio);
pmt->SetFormatType(&WMFORMAT_WaveFormatEx);
pmt->SetTemporalCompression(FALSE);
pmt->SetSubtype(&MEDIASUBTYPE_PCM);
pmt->SetSampleSize(lBufferSize);
return NOERROR;
} // GetMediaType
HRESULT CMemPlayStream::CheckMediaType(const CMediaType *pMediaType)
{
CheckPointer(pMediaType,E_POINTER);
if((*(pMediaType->Type()) != MEDIATYPE_Audio) || // we only output video
!(pMediaType->IsFixedSize())) // in fixed size samples
{
return E_INVALIDARG;
}
const GUID *SubType = pMediaType->Subtype();
if (SubType == NULL)
return E_INVALIDARG;
if(*SubType != MEDIASUBTYPE_PCM)
{
return E_INVALIDARG;
}
WAVEFORMATEX *pwi = (WAVEFORMATEX *) pMediaType->Format();
if((pwi->nChannels != 1) ||
(pwi->nSamplesPerSec != 44100) ||
(pwi->wBitsPerSample != 16))
{
return E_INVALIDARG;
}
return S_OK; // This format is acceptable.
} // CheckMediaType
HRESULT CMemPlayStream::DecideBufferSize(IMemAllocator *pAlloc,
ALLOCATOR_PROPERTIES *pProperties)
{
CheckPointer(pAlloc,E_POINTER);
CheckPointer(pProperties,E_POINTER);
CAutoLock cAutoLock(m_pFilter->pStateLock());
HRESULT hr = NOERROR;
WAVEFORMATEX *pwi = (WAVEFORMATEX *) m_mt.Format();
pProperties->cBuffers = 1;
pProperties->cbBuffer = pwi->nSamplesPerSec;
pProperties->cbAlign = pwi->nBlockAlign;
ASSERT(pProperties->cbBuffer);
ALLOCATOR_PROPERTIES Actual;
hr = pAlloc->SetProperties(pProperties,&Actual);
if(FAILED(hr))
{
return hr;
}
if(Actual.cbBuffer < pProperties->cbBuffer)
{
return E_FAIL;
}
ASSERT(Actual.cBuffers == 1);
return NOERROR;
} // DecideBufferSize
HRESULT CMemPlayStream::SetMediaType(const CMediaType *pMediaType)
{
CAutoLock cAutoLock(m_pFilter->pStateLock());
HRESULT hr = CSourceStream::SetMediaType(pMediaType);
if(SUCCEEDED(hr))
{
return NOERROR;
}
return hr;
} // SetMediaType
HRESULT CMemPlayStream::OnThreadCreate()
{
CAutoLock cAutoLockShared(&m_cSharedState);
m_rtSampleTime = 0;
return NOERROR;
} // OnThreadCreate
贴了一堆代码，把注释基本上都去掉了，没想到还是这么长。其实做的工作并不是很多，主要涉及到其中的三个函数，CMemPlayStream的初始化函数、fillbuffer函数和GetMediaType函数。
初始化函数把所有的音频祯的信息都按照原来的存储格式读出来，存储在四个数组当中，m_SampleSize[m_SampleCount]存放buffer的大小，m_DataList存放buffer的实际内容，m_StartTimeList和m_StopTimeList存放buffer的开始和结束时间。两个变量m_SampleCount对应于buffer的总数，m_SampleReaded对应于已经播放的buffer的个数。
fillbuffer将对应的音频祯的内容copy到IMediaSample当中去，同时设置这个sample的开始和结束时间。然后m_SampleReaded加1，再次请求fillbuffer时就播放下一个buffer的内容。当m_SampleReaded大于总的buffer个数m_SampleCoun后，fillbuffer返回S_FALSE结束音频的播放。
GetMediaType函数设置正确的音频配置信息，此处设置为44.1K的采样频率，双声道播放，每单位的数据为2个字节（16位）。如果捕获时不是按照这种格式设置的，可以进行相应的修改（好不方便奥，确实），否则播放出来就是一堆杂音，什么也听不清楚。
还有很多需要完善的地方，以后再说吧：
一下子把所有的数据都存储到内存中去了，如果文件很大行不通。
需要动态调整音频的配置信息。
4、音频祯的回放
编译这个程序，需要注意的是修改ball.def中的LIBRARY为MemPlay.ax代理原来Ball.ax，同时修改project－setting－link中的output file name为./Debug/MemPlay.ax替代原来的Ball.ax，注意编译成debug版本。在开始－运行中注册该filter，然后到graphedit中graph－insert filters－directshow filters中找到MemPlay，双击即可加入到graphedit中。右键单击MemPlay的output pin，选择render pin，或者自行加入一个音频播放的filter（在graph－insert filters－Audio Renders中选择default directsound device）。运行这个graph，就可以听到原来录制的声音拉。
（完）