我正在尝试根据我的Decklink SDI卡的流媒体来编写一个avi视频文件,在查看互联网后,我在这里写了这个代码我的问题是该程序没有写这里的文件代码:
#include <Windows.h>
#include <DShow.h>
#include <iostream>
int main(void)
{
IGraphBuilder* pGraph = NULL;
ICaptureGraphBuilder2* pBuild = NULL;
IMediaControl* pControl = NULL;
ICreateDevEnum* pDevEnum = NULL;
IEnumMoniker* pEnum = NULL;
IMoniker *pMoniker = NULL;
IMoniker* goodMoniker = NULL;
IBaseFilter* pCap;
HRESULT hr;
//Initialize pGraph
hr = CoInitialize(NULL);
hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void **) &pGraph);
if(FAILED(hr))
{
printf("ERROR - Could not initialize COM library");
return 1;
}
//Initialize pBuild
hr = CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL, CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void**) &pBuild);
if(FAILED(hr))
{
printf("ERROR - Could not create the Filter Graph Manager.");
return 2;
}
pBuild->SetFiltergraph(pGraph);
hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, reinterpret_cast<void**>(&pDevEnum));
if(SUCCEEDED(hr))
{
hr = pDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEnum, 0);
}
HWND hList;
while(pEnum->Next(1, &pMoniker, NULL) == S_OK)
{
IPropertyBag* pPropBag;
hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag, (void**)(&pPropBag));
if(FAILED(hr))
{
pMoniker->Release();
continue;
}
VARIANT varName;
VariantInit(&varName);
hr = pPropBag->Read(L"Description", &varName, 0);
if(FAILED(hr))
{
hr = pPropBag->Read(L"FriendlyName", &varName, 0);
}
if(SUCCEEDED(hr))
{
for(int i=0;i<20;i++)
{
std::cout<<(char)*(varName.bstrVal + i);
}
char yn;
std::cin>>yn;
if(yn=='Y')
{
std::cout<<"SUCCESSFUL"<<std::endl;
goodMoniker = pMoniker;
VariantClear(&varName);
}
}
pPropBag->Release();
if(pMoniker != goodMoniker)
{
pMoniker->Release();
}
}
hr = goodMoniker->BindToObject(0, 0, IID_IBaseFilter, (void**)(&pCap));
if(SUCCEEDED(hr))
{
hr = pGraph->AddFilter(pCap, L"Capture Filter");
}
IBaseFilter *pMux = NULL;
// hr = pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pCap, NULL, NULL);
hr = pBuild->SetOutputFileName(
&MEDIASUBTYPE_Avi, // Specifies AVI for the target file.
L"C:\\stuff.avi", // File name.
&pCap, // Receives a pointer to the mux.
NULL); // (Optional) Receives a pointer to the file sink.
hr =pBuild->RenderStream(
&PIN_CATEGORY_CAPTURE, // Pin category.
&MEDIATYPE_Video, // Media type.
pCap, // Capture filter.
NULL, // Intermediate filter (optional).
pMux); // Mux or file sink filter.
hr = pCap->QueryInterface(IID_IMediaControl,(void**) pControl);
printf("START ");
hr = pControl->Run();
Sleep(100000);
hr = pControl->Stop();
CoUninitialize();
pGraph->Release();
pBuild->Release();
pCap->Release();
}
这是我在尝试debbug时得到的错误消息:
Unhandled exception at 0x776015de in STREAMMMMM.exe: 0xC0000005: Access violation reading location 0x00000000.
程序崩溃了这一行:
r = pCap->QueryInterface(IID_IMediaControl,(void**) pControl);
答案 0 :(得分:3)
关于如何使用DirectShow在Internet上写入AVI,有几十个(如果不是数百个)示例。
这个特定的代码片段甚至没有开始写。它只准备管道,你甚至没有做IMediaControl::Run
,你应该做什么。此外,您应该等到写得足够多,然后停止录制,然后才释放接口指针。
看一下这个Q:Using a DirectShow filter without registering it, via a private CoCreateInstance,了解您开始实际捕获和编写时所缺少的内容(特别是IMediaControl::Run
和Sleep
)。