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// Here you get image video data in buf / len. Process it before calling Receive_ because renderer dealocates it.
HRESULT ( __stdcall * Receive_ ) ( void* inst, IMediaSample *smp ) ;
HRESULT __stdcall Receive ( void* inst, IMediaSample *smp )
{
BYTE* buf;
smp->GetPointer(&buf);
unsigned int len = smp->GetActualDataLength();
HRESULT ret = Receive_ ( inst, smp );
return ret;
}
int WINAPI WinMain(HINSTANCE inst,HINSTANCE prev,LPSTR cmd,int show)
{
HRESULT hr = CoInitialize(0);
MSG msg={0};
DWORD no;
IGraphBuilder* graph= 0; hr = CoCreateInstance( CLSID_FilterGraph, 0, CLSCTX_INPROC,IID_IGraphBuilder, (void **)&graph );
IMediaControl* ctrl = 0; hr = graph->QueryInterface( IID_IMediaControl, (void **)&ctrl );
ICreateDevEnum* devs = 0; hr = CoCreateInstance (CLSID_SystemDeviceEnum, 0, CLSCTX_INPROC, IID_ICreateDevEnum, (void **) &devs);
IEnumMoniker* cams = 0; hr = devs?devs->CreateClassEnumerator (CLSID_VideoInputDeviceCategory, &cams, 0):0;
IMoniker* mon = 0; hr = cams->Next (1,&mon,0); // get first found capture device (webcam?)
IBaseFilter* cam = 0; hr = mon->BindToObject(0,0,IID_IBaseFilter, (void**)&cam);
hr = graph->AddFilter(cam, L"Capture Source"); // add web cam to graph as source
IEnumPins* pins = 0; hr = cam?cam->EnumPins(&pins):0; // we need output pin to autogenerate rest of the graph
IPin* pin = 0; hr = pins?pins->Next(1,&pin, 0):0; // via graph->Render
hr = graph->Render(pin); // graph builder now builds whole filter chain including MJPG decompression on some webcams
IEnumFilters* fil = 0; hr = graph->EnumFilters(&fil); // from all newly added filters
IBaseFilter* rnd = 0; hr = fil->Next(1,&rnd,0); // we find last one (renderer)
hr = rnd->EnumPins(&pins); // because data we are intersted in are pumped to renderers input pin
hr = pins->Next(1,&pin, 0); // via Receive member of IMemInputPin interface
IMemInputPin* mem = 0; hr = pin->QueryInterface(IID_IMemInputPin,(void**)&mem);
if (!Receive_)
{
INT_PTR* p = 6 + *(INT_PTR**)mem;
VirtualProtect(&Receive_, 4, PAGE_EXECUTE_READWRITE, &no);
*(INT_PTR*) & Receive_ =*p;
VirtualProtect(p, 4, PAGE_EXECUTE_READWRITE,&no);
*p=(INT_PTR)Receive;
}
hr = ctrl->Run();
while ( GetMessage( &msg, 0, 0, 0 ) ) {
TranslateMessage( &msg );
DispatchMessage( &msg );
}
}; |
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