Я создал образец на основе этой ссылки MS:
https://docs.microsoft.com/en-us/windows/win32/directshow/using-the-sample-grabber
Код отображается ниже.
Но код захватывает только один кадр.Я думаю, что самый первый кадр в видео Но я хочу захватить каждый кадр, доступный в видеофайле.Как мне это сделать?
/*
for this sample to work you have to have
"C:\\temp\\FlickAnimation.avi"
and it will output the first frame to grab1.bmp
work out how to do all frames.
qedit.h from here:
https://social.msdn.microsoft.com/Forums/windowsdesktop/en-US/2ab5c212-5824-419d-b5d9-7f5db82f57cd/qedith-missing-in-current-windows-sdk-v70?forum=windowsdirectshowdevelopment
dshowutil.h from here:
https://raw.githubusercontent.com/microsoft/Windows-classic-samples/master/Samples/Win7Samples/multimedia/directshow/common/dshowutil.h
*/
#include <windows.h>
#include <dshow.h> // DirectShow main header
#include "qedit.h" // from Microsoft
#include <strmif.h> // for IMediaSample
#include <combaseapi.h> // IID_PPV_ARGS
#include "dshowutil.h" // from Microsoft
#pragma comment(lib, "strmiids.lib")
#pragma comment(lib, "dxguid.lib")
template <class T> void SafeRelease(T **ppT)
{
if (*ppT)
{
(*ppT)->Release();
*ppT = NULL;
}
}
HRESULT WriteBitmap(PCWSTR, BITMAPINFOHEADER*, size_t, BYTE*, size_t);
HRESULT GrabVideoBitmap(PCWSTR pszVideoFile, PCWSTR pszBitmapFile)
{
IGraphBuilder *pGraph = NULL;
IMediaControl *pControl = NULL;
IMediaEventEx *pEvent = NULL;
IBaseFilter *pGrabberF = NULL;
ISampleGrabber *pGrabber = NULL;
IBaseFilter *pSourceF = NULL;
IEnumPins *pEnum = NULL;
IPin *pPin = NULL;
IBaseFilter *pNullF = NULL;
BYTE *pBuffer = NULL;
HRESULT hr = CoCreateInstance(CLSID_FilterGraph, NULL,
CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pGraph));
if (FAILED(hr))
{
goto done;
}
hr = pGraph->QueryInterface(IID_PPV_ARGS(&pControl));
if (FAILED(hr))
{
goto done;
}
hr = pGraph->QueryInterface(IID_PPV_ARGS(&pEvent));
if (FAILED(hr))
{
goto done;
}
// Create the Sample Grabber filter.
hr = CoCreateInstance(CLSID_SampleGrabber, NULL, CLSCTX_INPROC_SERVER,
IID_PPV_ARGS(&pGrabberF));
if (FAILED(hr))
{
goto done;
}
hr = pGraph->AddFilter(pGrabberF, L"Sample Grabber");
if (FAILED(hr))
{
goto done;
}
hr = pGrabberF->QueryInterface(IID_PPV_ARGS(&pGrabber));
if (FAILED(hr))
{
goto done;
}
AM_MEDIA_TYPE mt;
ZeroMemory(&mt, sizeof(mt));
mt.majortype = MEDIATYPE_Video;
mt.subtype = MEDIASUBTYPE_RGB24;
hr = pGrabber->SetMediaType(&mt);
if (FAILED(hr))
{
goto done;
}
hr = pGraph->AddSourceFilter(pszVideoFile, L"Source", &pSourceF);
if (FAILED(hr))
{
goto done;
}
hr = pSourceF->EnumPins(&pEnum);
if (FAILED(hr))
{
goto done;
}
while (S_OK == pEnum->Next(1, &pPin, NULL))
{
hr = ConnectFilters(pGraph, pPin, pGrabberF);
SafeRelease(&pPin);
if (SUCCEEDED(hr))
{
break;
}
}
if (FAILED(hr))
{
goto done;
}
hr = CoCreateInstance(CLSID_NullRenderer, NULL, CLSCTX_INPROC_SERVER,
IID_PPV_ARGS(&pNullF));
if (FAILED(hr))
{
goto done;
}
hr = pGraph->AddFilter(pNullF, L"Null Filter");
if (FAILED(hr))
{
goto done;
}
hr = ConnectFilters(pGraph, pGrabberF, pNullF);
if (FAILED(hr))
{
goto done;
}
hr = pGrabber->SetOneShot(FALSE); // TRUE);
if (FAILED(hr))
{
goto done;
}
hr = pGrabber->SetBufferSamples(TRUE);
if (FAILED(hr))
{
goto done;
}
hr = pControl->Run();
if (FAILED(hr))
{
goto done;
}
long evCode;
hr = pEvent->WaitForCompletion(INFINITE, &evCode);
// Find the required buffer size.
long cbBuffer;
hr = pGrabber->GetCurrentBuffer(&cbBuffer, NULL);
if (FAILED(hr))
{
goto done;
}
pBuffer = (BYTE*)CoTaskMemAlloc(cbBuffer);
if (!pBuffer)
{
hr = E_OUTOFMEMORY;
goto done;
}
hr = pGrabber->GetCurrentBuffer(&cbBuffer, (long*)pBuffer);
if (FAILED(hr))
{
goto done;
}
hr = pGrabber->GetConnectedMediaType(&mt);
if (FAILED(hr))
{
goto done;
}
// Examine the format block.
if ((mt.formattype == FORMAT_VideoInfo) &&
(mt.cbFormat >= sizeof(VIDEOINFOHEADER)) &&
(mt.pbFormat != NULL))
{
VIDEOINFOHEADER *pVih = (VIDEOINFOHEADER*)mt.pbFormat;
hr = WriteBitmap(pszBitmapFile, &pVih->bmiHeader,
mt.cbFormat - SIZE_PREHEADER, pBuffer, cbBuffer);
}
else
{
// Invalid format.
hr = VFW_E_INVALIDMEDIATYPE;
}
FreeMediaType(mt);
done:
CoTaskMemFree(pBuffer);
SafeRelease(&pPin);
SafeRelease(&pEnum);
SafeRelease(&pNullF);
SafeRelease(&pSourceF);
SafeRelease(&pGrabber);
SafeRelease(&pGrabberF);
SafeRelease(&pControl);
SafeRelease(&pEvent);
SafeRelease(&pGraph);
return hr;
};
// Writes a bitmap file
// pszFileName: Output file name.
// pBMI: Bitmap format information (including pallete).
// cbBMI: Size of the BITMAPINFOHEADER, including palette, if present.
// pData: Pointer to the bitmap bits.
// cbData Size of the bitmap, in bytes.
HRESULT WriteBitmap(PCWSTR pszFileName, BITMAPINFOHEADER *pBMI, size_t cbBMI,
BYTE *pData, size_t cbData)
{
HANDLE hFile = CreateFile(pszFileName, GENERIC_WRITE, 0, NULL,
CREATE_ALWAYS, 0, NULL);
if (hFile == NULL)
{
return HRESULT_FROM_WIN32(GetLastError());
}
BITMAPFILEHEADER bmf = {};
bmf.bfType = 0x4d42; // 0x42 = "B" 0x4d = "M"
bmf.bfSize = cbBMI + cbData + sizeof(bmf);
bmf.bfOffBits = sizeof(bmf) + cbBMI;
DWORD cbWritten = 0;
BOOL result = WriteFile(hFile, &bmf, sizeof(bmf), &cbWritten, NULL);
if (result)
{
result = WriteFile(hFile, pBMI, cbBMI, &cbWritten, NULL);
}
if (result)
{
result = WriteFile(hFile, pData, cbData, &cbWritten, NULL);
}
HRESULT hr = result ? S_OK : HRESULT_FROM_WIN32(GetLastError());
CloseHandle(hFile);
return hr;
}
int main() {
// Initialize the COM library.
HRESULT hr = CoInitialize(NULL);
if (FAILED(hr))
{
printf("ERROR - Could not initialize COM library");
return 1;
}
GrabVideoBitmap(L"C:\\temp\\FlickAnimation.avi", L"grab1.bmp");
CoUninitialize();
}