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i'm trying to work with windows media fundation, get hang of it. I was following steps from this tutorial, and at some point i got stuck.
Let me describe my problem.
I am calling ActivateObject function from object IMFActivate.
This function call is presented in tutorial, I guess, in proper way, so I just copy-pasted it and didn't put a lot of thought on it.
After I completed all steps from tutorial (and wrapped it in class myself(!!)), I tried to run it, and HRESULT from that function call is E_POINTER which means that invalid pointer was passed.
I won't copy-paste my whole code, i'll narrow it down to objects used, and call itself.
Here is how function call looks like:
HRESULT MediaMultiplexer::AddTransformOutputNodes(
IMFTopology* pTopology,
IMFActivate* pSinkActivate,
IMFMediaType* pSourceType,
IMFTopologyNode** ppNode
)
{
if (!pTopology || !pSinkActivate || !pSourceType)
{
return E_INVALIDARG;
}
IMFTopologyNode* pEncNode = NULL;
IMFTopologyNode* pOutputNode = NULL;
IMFASFContentInfo* pContentInfo = NULL;
IMFASFProfile* pProfile = NULL;
IMFASFStreamConfig* pStream = NULL;
IMFMediaType* pMediaType = NULL;
IPropertyStore* pProps = NULL;
IMFActivate* pEncoderActivate = NULL;
IMFMediaSink* pSink = NULL;
GUID guidMT = GUID_NULL;
GUID guidMajor = GUID_NULL;
DWORD cStreams = 0;
WORD wStreamNumber = 0;
HRESULT hr = S_OK;
hr = pSourceType->GetMajorType(&guidMajor);
if (FAILED(hr))
{
goto done;
}
// Create the node.
hr = MFCreateTopologyNode(MF_TOPOLOGY_TRANSFORM_NODE, &pEncNode);
if (FAILED(hr))
{
goto done;
}
//Activate the sink
hr = pSinkActivate->ActivateObject(__uuidof(IMFMediaSink), (void**)&pSink); //THIS CALL!!!!!
if (FAILED(hr))
{
goto done;
}
//find the media type in the sink
//Get content info from the sink
hr = pSink->QueryInterface(__uuidof(IMFASFContentInfo), (void**)&pContentInfo);
if (FAILED(hr))
{
goto done;
}
And here is how i prepare IMFActivate used to call that function:
bool MediaMultiplexer::setFileName(std::string _fileName)
{
HRESULT hr;
hr = MFCreateASFMediaSinkActivate(std::wstring(_fileName.begin(), _fileName.end()).c_str(), m_globalContentInfo, &m_globalActivate);
if (FAILED(hr))
{
printError("Failed creating ASF media sink activate", hr);
return false;
}
m_globalActivate->AddRef();
return true;
}
I just started working with MediaFundation so I don't know how important that is, so I'll show how i prepare contentInfo aswell, which is used to create IMFActivate.
HRESULT hr;
hr = MFCreateASFContentInfo(&m_globalContentInfo);
if (FAILED(hr))
{
printError("Failed to create global content info", hr);
return false;
}
PROPVARIANT var;
var.vt = VT_BOOL;
var.boolVal = VARIANT_TRUE;
hr = m_globalContentInfo->GetEncodingConfigurationPropertyStore(0, &m_globalStore);
if (FAILED(hr))
{
printError("Failed getting global store configuration", hr);
return false;
}
hr = m_globalStore->SetValue(MFPKEY_ASFMEDIASINK_AUTOADJUST_BITRATE, var);
if (FAILED(hr))
{
printError("Failed setting value for bitrat adjust", hr);
return false;
}
Hope someone can help me, and thus, in future, anyone with similar issue will find his answer here :).
And i'm sorry for any sort of english related mistakes, i'm still just learning this language.
I am stupid :)
I found mistake in my code.
While setting m_globalContentInfo i forgot to set profile.
In code it should be something like that:
//...
hr = m_globalStore->SetValue(MFPKEY_ASFMEDIASINK_AUTOADJUST_BITRATE, var);
if (FAILED(hr))
{
printError("Failed setting value for bitrat adjust", hr);
return false;
}
// I missed that part ealier
hr = m_globalContentInfo->SetProfile(m_profile);
if (FAILED(hr))
{
printError("Failed setting global profile");
return false;
}
I'm attempting to host a file preview handler within a dialog. I've set up an event sink for selection changes in Explorer. When the selection changes, I feed the selected shell item to the dialog, which in turn feeds it to a function that prepares the preview frame.
In general, it successfully loads the correct handler and displays the contents of the file, but for certain file types (namely, Excel and Word files), it runs into various problems like focus-loss or flashing. Here's a demo of the Excel preview handler messing up focus (and by mess up, I mean it wrongfully steals the focus from Explorer, which I'd like to maintain focus):
Word files may load successfully once, but they'll subsequently fail, especially if Word is opened.
As for the code:
For starters, here's my function for obtaining the preview handler from the file extension. This seems to work fine:
HRESULT PreviewHandlerFromExt(LPCWSTR pszExt, IPreviewHandler** ppph)
{
WCHAR szCLSID[CLSID_LEN] = { 0 };
DWORD cchOut = CLSID_LEN;
HRESULT hr = AssocQueryString( ASSOCF_INIT_DEFAULTTOSTAR,
ASSOCSTR_SHELLEXTENSION,
pszExt,
L"{8895b1c6-b41f-4c1c-a562-0d564250836f}",
szCLSID,
&cchOut );
if (FAILED(hr))
{
return hr;
}
CLSID clsid;
hr = CLSIDFromString(szCLSID, &clsid);
if (FAILED(hr))
{
return hr;
}
CComPtr<IUnknown> punk;
hr = punk.CoCreateInstance(clsid, NULL, CLSCTX_LOCAL_SERVER);
if (FAILED(hr))
{
return hr;
}
CComPtr<IPreviewHandler> pPrevHandler;
hr = punk->QueryInterface(&pPrevHandler);
if (FAILED(hr) || !pPrevHandler)
{
return hr;
}
return pPrevHandler.CopyTo(ppph);
}
And now here's the function in my dialog that prepares the preview, given a shell item (m_pPreviewHandler is the active preview handler, IDC_PREVIEWFRAME is a placeholder in the dialog for the preview pane, and m_mapExtsToPreviewHandlers is just a map for storing preview handlers as the user comes across them):
void CMyDialog::ShowPreview(IShellItem* pShItem)
{
HRESULT hr;
if (m_pPreviewHandler)
{
m_pPreviewHandler->Unload();
m_pPreviewHandler.Release();
}
CComHeapPtr<WCHAR> pszPath;
hr = pShItem->GetDisplayName(SIGDN_FILESYSPATH, &pszPath);
if (FAILED(hr))
{
return;
}
LPWSTR pszExt = CharLower(PathFindExtension(pszPath));
auto it = m_mapExtsToPreviewHandlers.find(pszExt);
if (it == m_mapExtsToPreviewHandlers.end())
{
hr = PreviewHandlerFromExt(pszExt, &m_pPreviewHandler);
if (FAILED(hr) || !m_pPreviewHandler)
{
return;
}
m_mapExtsToPreviewHandlers[pszExt] = m_pPreviewHandler;
}
else
{
m_pPreviewHandler = m_mapExtsToPreviewHandlers[pszExt];
}
CComPtr<IInitializeWithFile> pInitWithFile;
hr = m_pPreviewHandler->QueryInterface(&pInitWithFile);
if (SUCCEEDED(hr))
{
hr = pInitWithFile->Initialize(pszPath, STGM_READ);
if (FAILED(hr))
{
return;
}
}
else
{
CComPtr<IInitializeWithStream> pInitWithStream;
hr = m_pPreviewHandler->QueryInterface(&pInitWithStream);
if (SUCCEEDED(hr))
{
CComPtr<IStream> pStream;
hr = SHCreateStreamOnFile(pszPath, STGM_READ, &pStream);
if (FAILED(hr) || !pStream)
{
return;
}
hr = pInitWithStream->Initialize(pStream, STGM_READ);
if (FAILED(hr))
{
return;
}
}
}
CWindow wndPreviewFrame( GetDlgItem(IDC_PREVIEWFRAME) );
CRect rectPreviewFrame;
wndPreviewFrame.GetClientRect(&rectPreviewFrame);
hr = m_pPreviewHandler->SetWindow(wndPreviewFrame, &rectPreviewFrame);
if (FAILED(hr))
{
return;
}
hr = m_pPreviewHandler->DoPreview();
if (FAILED(hr))
{
return;
}
hr = m_pPreviewHandler->SetRect(&rectPreviewFrame);
if (FAILED(hr))
{
return;
}
}
Does anyone know what I'm doing wrong or what might fix these focus problems?
I've also tried placing LockSetForegroundWindow at various places, but no lock.
Also, this is what the dialog resource looks like:
I could capture the image from webcam and save it as bitmap by using sampleGrabber. And I know I could use the IAMStreamConfig interface to GetFormat and SetFormat the video resolution. My question is, I using FindInterface() to get IAMStreamConfig* but always failed.Is it because I place it in a wrong place or something else I didn't notice. I placed it before RenderStream. Here are some code below, thanks for your patient and help!
INT USBDeviceApp::GetInterfaces()
{
HRESULT hr;
hr = CoCreateInstance (CLSID_FilterGraph, NULL, CLSCTX_INPROC,
IID_IGraphBuilder, (void **) &pGraphBuilder);
if (FAILED(hr))
return hr;
hr = CoCreateInstance (CLSID_CaptureGraphBuilder2 , NULL, CLSCTX_INPROC,
IID_ICaptureGraphBuilder2, (void **) &pCaptureGraphBuilder2);
if (FAILED(hr))
return hr;
hr = pGraphBuilder->QueryInterface(IID_IMediaControl,(LPVOID *)
&pMediaControl);
if (FAILED(hr))
return hr;
hr = pGraphBuilder->QueryInterface(IID_IVideoWindow, (LPVOID *)
&pVideoWindow);
if(FAILED(hr))
{
return hr;
}
hr = pGraphBuilder->QueryInterface(IID_IMediaEvent,(LPVOID *)
&pMediaEvent);
if(FAILED(hr))
{
return hr;
}
// ------------------------
// Create the Sample Grabber.
hr = CoCreateInstance(CLSID_SampleGrabber, NULL, CLSCTX_INPROC_SERVER,
IID_IBaseFilter, (void**)&pGrabberF);
if (FAILED(hr))
{
return hr;
}
hr = pGrabberF->QueryInterface(IID_ISampleGrabber,
(void**)&pSampleGrabber);
if(FAILED(hr))
{
AfxMessageBox(_T("Error SampleGrabber QueryInterface"));
}
return 1;
}
INT USBDeviceApp::InitMonikers()
{
HRESULT hr;
ULONG cFetched;
ICreateDevEnum *pCreateDevEnum;
hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL,
CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (void**)&pCreateDevEnum);
if (FAILED(hr))
{
return hr;
}
IEnumMoniker *pEnumMoniker;
hr = pCreateDevEnum->
CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pEnumMoniker, 0);
if (FAILED(hr) || !pEnumMoniker)
{
return -1;
}
hr = pEnumMoniker->Next(1, &pMonikerVideo, &cFetched);
if (S_OK == hr)
{
hr = pMonikerVideo->BindToObject(0,0,IID_IBaseFilter,
(void**)&pVideoCaptureFilter);
if (FAILED(hr))
{
return hr;
}
}
pEnumMoniker->Release();
return 1;
}
INT USBDeviceApp::CaptureVideo()
{
HRESULT hr = CoInitialize(NULL);
hr = GetInterfaces();
if (FAILED(hr))
{
AfxMessageBox(_T("Failed to get video interfaces!"));
return hr;
}
hr = pCaptureGraphBuilder2->SetFiltergraph(pGraphBuilder);
if (FAILED(hr))
{
AfxMessageBox(_T("Failed to attach the filter graph to the capture graph!"));
return hr;
}
//IAMStreamConfig *pConfig
hr = pCaptureGraphBuilder2->FindInterface(&PIN_CATEGORY_PREVIEW,
&MEDIATYPE_Video,
pVideoCaptureFilter,IID_IAMStreamConfig, (void **)&pConfig);
if (FAILED(hr))
{
AfxMessageBox(_T("Couldn't initialize IAMStreamConfig!"));
}
else
{////
int iCount = 0,iSize = 0;
hr = pConfig->GetNumberOfCapabilities(&iCount,&iSize);
if(iSize == sizeof(VIDEO_STREAM_CONFIG_CAPS))
{
for(int iFormat = 0;iFormat < iCount;iFormat++)
{
VIDEO_STREAM_CONFIG_CAPS scc;
AM_MEDIA_TYPE *pmtConfig;
hr = pConfig->GetStreamCaps(iFormat, &pmtConfig, (BYTE*)&scc);
if(hr)
{
if((pmtConfig->majortype == MEDIATYPE_Video) &&
(pmtConfig->subtype == MEDIASUBTYPE_RGB24) &&
(pmtConfig->formattype == FORMAT_VideoInfo) &&
(pmtConfig->cbFormat >= sizeof (VIDEOINFOHEADER)) &&
(pmtConfig->pbFormat != NULL))
{
VIDEOINFOHEADER *pVih = (VIDEOINFOHEADER*)pmtConfig->pbFormat;
pVih->bmiHeader.biWidth = 1280;
pVih->bmiHeader.biHeight = 720;
pVih->bmiHeader.biSizeImage = DIBSIZE(pVih->bmiHeader);
hr = pConfig->SetFormat(pmtConfi);
}
DeleteMediaType(pmtConfig);
}
}
}
}////
hr = InitMonikers();
if(FAILED(hr))
{
return hr;
}
hr = pGraphBuilder->AddFilter(pVideoCaptureFilter, L"Video Capture");
if (FAILED(hr))
{
pVideoCaptureFilter->Release();
return hr;
}
AM_MEDIA_TYPE mt;
ZeroMemory(&mt, sizeof(AM_MEDIA_TYPE));
mt.majortype = MEDIATYPE_Video;
mt.subtype = MEDIASUBTYPE_RGB24;
hr = pSampleGrabber->SetMediaType(&mt);
hr = pSampleGrabber->SetOneShot(FALSE);
hr = pSampleGrabber->SetBufferSamples(TRUE);
hr = pGraphBuilder->AddFilter(pGrabberF, L"Sample Grabber");
if (FAILED(hr))
{
return hr;
}
hr = pCaptureGraphBuilder2->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pVideoCaptureFilter, pGrabberF, 0 );
if (FAILED(hr))
{
pVideoCaptureFilter->Release();
return hr;
}
hr = pSampleGrabber->GetConnectedMediaType( &mt );
if(FAILED( hr ))
{
return -1;
}
VIDEOINFOHEADER * vih = (VIDEOINFOHEADER*) mt.pbFormat;
pVih = (VIDEOINFOHEADER*) mt.pbFormat;
CSampleGrabberCB *CB = new CSampleGrabberCB() ;
if(!FAILED( hr ))
{
CB->Width = vih->bmiHeader.biWidth;
CB->Height = vih->bmiHeader.biHeight;
FreeMediaType( mt );
}
hr = pSampleGrabber->SetCallback( CB, 1 );
pVideoCaptureFilter->Release();
this->SetUpVideoWindow();
hr = pMediaControl->Run();
if (FAILED(hr))
{
return hr;
}
return hr;
}
hr = pCaptureGraphBuilder2->FindInterface()
always failed to get the IAMStreamConfig interface, I really don't know why. Can someone help me, thanks so much!
Your API call below
pCaptureGraphBuilder2->FindInterface(&PIN_CATEGORY_PREVIEW,
&MEDIATYPE_Video,
pVideoCaptureFilter,IID_IAMStreamConfig, (void **) &pConfig);
applies several restrictions to the search, including pin category: you are looking for a preview pin. For example, the graph below features three video capture devices and none of them has the dedicated preview pin: preview pin is optional.
You need to take this into account and either relax the search criteria or I would rather suggest that you locate the pin of your interest directly on the capture filter. Then you will set it and and connect it with downstream peer filters. FindInterface is powerful but it also adds chances to get into confusion.
I am having trouble with a video recording application that I am writing using Microsoft Media Foundation.
Specifically, the read/write function (which I put on a loop that lives on it's own thread) doesn't make it pass the call to ReadSample:
HRESULT WinCapture::rwFunction(void) {
HRESULT hr;
DWORD streamIndex, flags;
LONGLONG llTimeStamp;
IMFSample *pSample = NULL;
EnterCriticalSection(&m_critsec);
// Read another sample.
hr = m_pReader->ReadSample(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
0,
&streamIndex, // actual
&flags,//NULL, // flags
&llTimeStamp,//NULL, // timestamp
&pSample // sample
);
if (FAILED(hr)) { goto done; }
hr = m_pWriter->WriteSample(0, pSample);
goto done;
done:
return hr;
SafeRelease(&pSample);
LeaveCriticalSection(&m_critsec);
}
The value of hr is an exception code: 0xc00d3704 so the code snippet skips the call to WriteSample.
It is a lot of steps, but I am fairly certain that I am setting up m_pReader (type IMFSource *) correctly.
HRESULT WinCapture::OpenMediaSource(IMFMediaSource *pSource)
{
HRESULT hr = S_OK;
IMFAttributes *pAttributes = NULL;
hr = MFCreateAttributes(&pAttributes, 2);
// use a callback
//if (SUCCEEDED(hr))
//{
// hr = pAttributes->SetUnknown(MF_SOURCE_READER_ASYNC_CALLBACK, this);
//}
// set the desired format type
DWORD dwFormatIndex = (DWORD)formatIdx;
IMFPresentationDescriptor *pPD = NULL;
IMFStreamDescriptor *pSD = NULL;
IMFMediaTypeHandler *pHandler = NULL;
IMFMediaType *pType = NULL;
// create the source reader
if (SUCCEEDED(hr))
{
hr = MFCreateSourceReaderFromMediaSource(
pSource,
pAttributes,
&m_pReader
);
}
// steps to set the selected format type
hr = pSource->CreatePresentationDescriptor(&pPD);
if (FAILED(hr))
{
goto done;
}
BOOL fSelected;
hr = pPD->GetStreamDescriptorByIndex(0, &fSelected, &pSD);
if (FAILED(hr))
{
goto done;
}
hr = pSD->GetMediaTypeHandler(&pHandler);
if (FAILED(hr))
{
goto done;
}
hr = pHandler->GetMediaTypeByIndex(dwFormatIndex, &pType);
if (FAILED(hr))
{
goto done;
}
hr = pHandler->SetCurrentMediaType(pType);
{
goto done;
}
hr = m_pReader->SetCurrentMediaType(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
NULL,
pType
);
// set to maximum framerate?
hr = pHandler->GetCurrentMediaType(&pType);
if (FAILED(hr))
{
goto done;
}
// Get the maximum frame rate for the selected capture format.
// Note: To get the minimum frame rate, use the
// MF_MT_FRAME_RATE_RANGE_MIN attribute instead.
PROPVARIANT var;
if (SUCCEEDED(pType->GetItem(MF_MT_FRAME_RATE_RANGE_MAX, &var)))
{
hr = pType->SetItem(MF_MT_FRAME_RATE, var);
PropVariantClear(&var);
if (FAILED(hr))
{
goto done;
}
hr = pHandler->SetCurrentMediaType(pType);
{
goto done;
}
hr = m_pReader->SetCurrentMediaType(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
NULL,
pType
);
}
goto done;
done:
SafeRelease(&pPD);
SafeRelease(&pSD);
SafeRelease(&pHandler);
SafeRelease(&pType);
SafeRelease(&pAttributes);
return hr;
}
This code is all copied from Microsoft documentation pages and the SDK sample code. The variable formatIdx is 0, I get it from enumerating the camera formats and choosing the first one.
UPDATE
I have rewritten this program so that it uses callbacks instead of a blocking read/write function and I have exactly the same issue.
Here I get the device and initiate the callback method:
HRESULT WinCapture::initCapture(const WCHAR *pwszFileName, IMFMediaSource *pSource) {
HRESULT hr = S_OK;
EncodingParameters params;
params.subtype = MFVideoFormat_WMV3; // TODO, paramterize this
params.bitrate = TARGET_BIT_RATE;
m_llBaseTime = 0;
IMFMediaType *pType = NULL;
DWORD sink_stream = 0;
EnterCriticalSection(&m_critsec);
hr = m_ppDevices[selectedDevice]->ActivateObject(IID_PPV_ARGS(&pSource));
//m_bIsCapturing = false; // this is set externally here
if (SUCCEEDED(hr))
hr = OpenMediaSource(pSource); // also creates the reader
if (SUCCEEDED(hr))
{
hr = m_pReader->GetCurrentMediaType(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
&pType
);
}
// Create the sink writer
if (SUCCEEDED(hr))
{
hr = MFCreateSinkWriterFromURL(
pwszFileName,
NULL,
NULL,
&m_pWriter
);
}
if (SUCCEEDED(hr))
hr = ConfigureEncoder(params, pType, m_pWriter, &sink_stream);
// kick off the recording
if (SUCCEEDED(hr))
{
m_llBaseTime = 0;
m_bIsCapturing = TRUE;
hr = m_pReader->ReadSample(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
0,
NULL,
NULL,
NULL,
NULL
);
}
SafeRelease(&pType);
SafeRelease(&pSource);
pType = NULL;
LeaveCriticalSection(&m_critsec);
return hr;
}
The OpenMediaSource method is here:
HRESULT WinCapture::OpenMediaSource(IMFMediaSource *pSource)
{
HRESULT hr = S_OK;
IMFAttributes *pAttributes = NULL;
hr = MFCreateAttributes(&pAttributes, 2);
// use a callback
if (SUCCEEDED(hr))
{
hr = pAttributes->SetUnknown(MF_SOURCE_READER_ASYNC_CALLBACK, this);
}
// set the desired format type
DWORD dwFormatIndex = (DWORD)formatIdx;
IMFPresentationDescriptor *pPD = NULL;
IMFStreamDescriptor *pSD = NULL;
IMFMediaTypeHandler *pHandler = NULL;
IMFMediaType *pType = NULL;
// create the source reader
if (SUCCEEDED(hr))
{
hr = MFCreateSourceReaderFromMediaSource(
pSource,
pAttributes,
&m_pReader
);
}
// steps to set the selected format type
if (SUCCEEDED(hr)) hr = pSource->CreatePresentationDescriptor(&pPD);
if (FAILED(hr))
{
goto done;
}
BOOL fSelected;
hr = pPD->GetStreamDescriptorByIndex(0, &fSelected, &pSD);
if (FAILED(hr))
{
goto done;
}
hr = pSD->GetMediaTypeHandler(&pHandler);
if (FAILED(hr))
{
goto done;
}
hr = pHandler->GetMediaTypeByIndex(dwFormatIndex, &pType);
if (FAILED(hr))
{
goto done;
}
hr = pHandler->SetCurrentMediaType(pType);
if (FAILED(hr))
{
goto done;
}
// get available framerates
hr = MFGetAttributeRatio(pType, MF_MT_FRAME_RATE, &frameRate, &denominator);
std::cout << "frameRate " << frameRate << " denominator " << denominator << std::endl;
hr = m_pReader->SetCurrentMediaType(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
NULL,
pType
);
// set to maximum framerate?
hr = pHandler->GetCurrentMediaType(&pType);
if (FAILED(hr))
{
goto done;
}
goto done;
done:
SafeRelease(&pPD);
SafeRelease(&pSD);
SafeRelease(&pHandler);
SafeRelease(&pType);
SafeRelease(&pAttributes);
return hr;
}
Here, formatIdx is a field of this class that get sets by the user via the GUI. I leave it 0 in order to test. So, I don't think I am missing any steps to get the camera going, but maybe I am.
When I inspect what applications are using the webcam (using this method) after the call to ActivateObject, I see that my application is using the webcam as expected. But, when I enter the callback routine, I see there are two instances of my application using the webcam. This is the same using a blocking method.
I don't know if that is good or bad, but when I enter my callback method:
HRESULT WinCapture::OnReadSample(
HRESULT hrStatus,
DWORD /*dwStreamIndex*/,
DWORD /*dwStreamFlags*/,
LONGLONG llTimeStamp,
IMFSample *pSample // Can be NULL
)
{
EnterCriticalSection(&m_critsec);
if (!IsCapturing() || m_bIsCapturing == false)
{
LeaveCriticalSection(&m_critsec);
return S_OK;
}
HRESULT hr = S_OK;
if (FAILED(hrStatus))
{
hr = hrStatus;
goto done;
}
if (pSample)
{
if (m_bFirstSample)
{
m_llBaseTime = llTimeStamp;
m_bFirstSample = FALSE;
}
// rebase the time stamp
llTimeStamp -= m_llBaseTime;
hr = pSample->SetSampleTime(llTimeStamp);
if (FAILED(hr)) { goto done; }
hr = m_pWriter->WriteSample(0, pSample);
if (FAILED(hr)) { goto done; }
}
// Read another sample.
hr = m_pReader->ReadSample(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
0,
NULL, // actual
NULL, // flags
NULL, // timestamp
NULL // sample
);
done:
if (FAILED(hr))
{
//NotifyError(hr);
}
LeaveCriticalSection(&m_critsec);
return hr;
}
hrStatus is the 0x00d3704 error I was getting before, and the callback goes straight to done thus killing the callbacks.
Finally, I should say that I am modeling (read, 'copying') my code from the example MFCaptureToFile in the Windows SDK Samples and that doesn't work either. Although, there I get this weird negative number for the failed HRESULT: -1072875772.
If you have got error [0xC00D3704] - it means that source does not initialized. Such error can be caused by mistake of initialization, busy camera by another application (process) or unsupport of the camera by UVC driver(old cameras support DirectShow driver with partly compatibleness with UVC. It is possible read some general info from old cameras via UVC as friendly name, symbolic link. However, old cameras support DirectShow models - PUSH, while camera pushes bytes into the pipeline, while Media Foundation PULL data - sends special signal and wait data).
For checking your code I would like advise to research articles about capturing video from web cam on site "CodeProject" - search "videoInput" name.
So we have a simple C++ win32 console app. All we want is to print list of web cameras and other video capture devices that are avaliable. We want to use windows apis as much as possible - no external libs - after all - all we want is to print out a a list - not to fly onto the moon!) How to do such thing?
My own reserch:
I found this official msdn sample but I still do not get how to output device list onto screen=( (sorry - I am new to C++)
... some more reserch...
In one of simpliest ms samples on topic found this
HRESULT OnInitDialog(HWND hwnd, ChooseDeviceParam *pParam)
{
HRESULT hr = S_OK;
HWND hList = GetDlgItem(hwnd, IDC_DEVICE_LIST);
// Display a list of the devices.
for (DWORD i = 0; i < pParam->count; i++)
{
WCHAR *szFriendlyName = NULL;
hr = pParam->ppDevices[i]->GetAllocatedString(
MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME,
&szFriendlyName,
NULL
);
if (FAILED(hr))
{
break;
}
int index = ListBox_AddString(hList, szFriendlyName);
ListBox_SetItemData(hList, index, i);
CoTaskMemFree(szFriendlyName);
}
looks like it should do the job but I do not get how to include this into simple command line app so to output data...
also from this series:
How to get a list of video capture devices on linux? and special details on getting cameras NAMES with correct, tested answers
How to get a list of video capture devices on Mac OS? with correct, not yet tested by my answers
How to get a list of video capture devices on windows? with correct, tested answers
How to get a list video capture devices NAMES using Qt (crossplatform)?
From the examples shown, copy the following code into dev.c. Then open the command line with all the SDK variables set. At the command line link to ole32.lib and oleaut32.lib. It will then show you all the devices.
cl dev.c ole32.lib oleaut32.lib
dev.exe will give out the list on the command line.
#include <windows.h>
#include <dshow.h>
#pragma comment(lib, "strmiids")
HRESULT EnumerateDevices(REFGUID category, IEnumMoniker **ppEnum)
{
// Create the System Device Enumerator.
ICreateDevEnum *pDevEnum;
HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL,
CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pDevEnum));
if (SUCCEEDED(hr))
{
// Create an enumerator for the category.
hr = pDevEnum->CreateClassEnumerator(category, ppEnum, 0);
if (hr == S_FALSE)
{
hr = VFW_E_NOT_FOUND; // The category is empty. Treat as an error.
}
pDevEnum->Release();
}
return hr;
}
void DisplayDeviceInformation(IEnumMoniker *pEnum)
{
IMoniker *pMoniker = NULL;
while (pEnum->Next(1, &pMoniker, NULL) == S_OK)
{
IPropertyBag *pPropBag;
HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag));
if (FAILED(hr))
{
pMoniker->Release();
continue;
}
VARIANT var;
VariantInit(&var);
// Get description or friendly name.
hr = pPropBag->Read(L"Description", &var, 0);
if (FAILED(hr))
{
hr = pPropBag->Read(L"FriendlyName", &var, 0);
}
if (SUCCEEDED(hr))
{
printf("%S\n", var.bstrVal);
VariantClear(&var);
}
hr = pPropBag->Write(L"FriendlyName", &var);
// WaveInID applies only to audio capture devices.
hr = pPropBag->Read(L"WaveInID", &var, 0);
if (SUCCEEDED(hr))
{
printf("WaveIn ID: %d\n", var.lVal);
VariantClear(&var);
}
hr = pPropBag->Read(L"DevicePath", &var, 0);
if (SUCCEEDED(hr))
{
// The device path is not intended for display.
printf("Device path: %S\n", var.bstrVal);
VariantClear(&var);
}
pPropBag->Release();
pMoniker->Release();
}
}
void main()
{
HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
if (SUCCEEDED(hr))
{
IEnumMoniker *pEnum;
hr = EnumerateDevices(CLSID_VideoInputDeviceCategory, &pEnum);
if (SUCCEEDED(hr))
{
DisplayDeviceInformation(pEnum);
pEnum->Release();
}
hr = EnumerateDevices(CLSID_AudioInputDeviceCategory, &pEnum);
if (SUCCEEDED(hr))
{
DisplayDeviceInformation(pEnum);
pEnum->Release();
}
CoUninitialize();
}
}
How to let user select a video recording device (web-cam) with OpenCV?
the answer isnt opencv specific
Here is C++ code to list connected webcams on a windows machine without any additional libraries
/* List connected webcams on windows machine
Build: g++ cameralist.cpp -lstrmiids -lole32 -loleaut32
microsoft docs https://learn.microsoft.com/en-us/windows/win32/directshow/using-the-system-device-enumerator
*/
#include <windows.h>
#include <dshow.h>
HRESULT EnumerateDevices(REFGUID category, IEnumMoniker **ppEnum)
{
// Create the System Device Enumerator.
HRESULT hr;
ICreateDevEnum *pDevEnum = NULL;
hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,
IID_ICreateDevEnum, (void **)&pDevEnum);
if (SUCCEEDED(hr))
{
// Create an enumerator for the category.
hr = pDevEnum->CreateClassEnumerator(category, ppEnum, 0);
if (hr == S_FALSE)
{
hr = VFW_E_NOT_FOUND; // The category is empty. Treat as an error.
}
pDevEnum->Release();
}
return hr;
}
void DisplayDeviceInformation(IEnumMoniker *pEnum)
{
IMoniker *pMoniker = NULL;
while (pEnum->Next(1, &pMoniker, NULL) == S_OK)
{
IPropertyBag *pPropBag;
HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag));
if (FAILED(hr))
{
pMoniker->Release();
continue;
}
VARIANT var;
VariantInit(&var);
// Get description or friendly name.
hr = pPropBag->Read(L"Description", &var, 0);
if (FAILED(hr))
{
hr = pPropBag->Read(L"FriendlyName", &var, 0);
}
if (SUCCEEDED(hr))
{
printf("%S\n", var.bstrVal);
VariantClear(&var);
}
hr = pPropBag->Write(L"FriendlyName", &var);
hr = pPropBag->Read(L"DevicePath", &var, 0);
if (SUCCEEDED(hr))
{
// The device path is not intended for display.
printf("Device path: %S\n", var.bstrVal);
VariantClear(&var);
}
pPropBag->Release();
pMoniker->Release();
}
}
int main()
{
HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
if (SUCCEEDED(hr))
{
IEnumMoniker *pEnum;
hr = EnumerateDevices(CLSID_VideoInputDeviceCategory, &pEnum);
if (SUCCEEDED(hr))
{
DisplayDeviceInformation(pEnum);
pEnum->Release();
}
CoUninitialize();
}
return 0;
}