Click here to Skip to main content
15,307,172 members
Articles / Programming Languages / C++
Posted 11 May 2014

Tagged as


5 bookmarked

Custom Media Sink for Use with Media Foundation Topologies and WinRT/WRL MediaCapture

Rate me:
Please Sign up or sign in to vote.
4.50/5 (3 votes)
26 Dec 2015CPOL1 min read
Custom Media Sink for use with Media Foundation Topologies and WinRT/WRL MediaCapture


WinRT and WRL introduce the requirement that most Media Foundation interfaces can no longer be directly created. If one wants to record audio or video through a sink, the only way to do so is with quite literally hundreds to thousands of lines of code in a custom sink. This prototype will get someone started towards achieving that with greater ease. Native C++ and C++/CX compatible. This is also compatible with non-WinRT/non-WRL uses since custom sinks could also be used prior to Windows 8 but generally shortcut interfaces were used.


Knowledge of WinRT, WRL, C++, C++/CX, MediaCapture, Media Foundation, ATL and COM are recommended.

Using the Code

The block of code here is for all scenarios including non-WinRT/non-WRL cases where it is bound as an output node of a topology.

#ifdef _WINRT_DLL
#ifdef __cplusplus_winrt
Windows::Media::MediaProperties::VideoEncodingProperties^ vidProps;
Windows::Media::MediaProperties::AudioEncodingProperties^ audProps;
Windows::Media::MediaProperties::MediaEncodingProfile^ medEncProf = 
        ref new Windows::Media::MediaProperties::MediaEncodingProfile;
medEncProf->Video = vidProps;
medEncProf->Audio = audProps;
//set any properties to pass to the Custom Sink in a PropertySet as a best practice
Windows::Foundation::Collections::IPropertySet^ pSet = 
        ref new Windows::Foundation::Collections::PropertySet();
Windows::Media::Capture::MediaCapture^ medCap;
HRESULT hr = medCap->StartPreviewToCustomSinkAsync(medEncProf, 
    ref new Platform::String(RuntimeClass_TimeStamp_WebCamSecExtensions_MediaSink), pSet);
//when finished
hr = medCap->StopPreviewAsync();
ABI::Windows::Media::Capture::IMediaCapture* medCap;
ABI::Windows::Media::MediaProperties::IVideoEncodingProperties* vidProps;
ABI::Windows::Media::MediaProperties::IAudioEncodingProperties* audProps;
ABI::Windows::Foundation::IAsyncAction** pAction;
Microsoft::WRL::ComPtr<ABI::Windows::Media::Capture::IMediaCaptureVideoPreview> imedPrevCap;
if (pAction == nullptr) return E_POINTER;
hr = medCap->QueryInterface<ABI::Windows::Media::Capture::IMediaCaptureVideoPreview>(&imedPrevCap);
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<IActivationFactory> objFactory;
hr = Windows::Foundation::GetActivationFactory(Microsoft::WRL::Wrappers::HStringReference
    (RuntimeClass_Windows_Media_MediaProperties_MediaEncodingProfile).Get(), objFactory.ReleaseAndGetAddressOf());
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<IInspectable> medEncProf;
hr = objFactory->ActivateInstance(medEncProf.ReleaseAndGetAddressOf());
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<ABI::Windows::Media::MediaProperties::IMediaEncodingProfile> encProps;
hr = medEncProf.As<ABI::Windows::Media::MediaProperties::IMediaEncodingProfile>(&encProps);
if (FAILED(hr)) return hr;
hr = encProps->put_Video(vidProps);
if (FAILED(hr)) return hr;
//if audio desired must also set an audio sink stream
hr = encProps->put_Audio(audProps);
if (FAILED(hr)) return hr;
hr = Windows::Foundation::GetActivationFactory(Microsoft::WRL::Wrappers::HStringReference
    (RuntimeClass_Windows_Foundation_Collections_PropertySet).Get(), objFactory.ReleaseAndGetAddressOf());
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<IInspectable> pSet;
hr = objFactory->ActivateInstance(pSet.GetAddressOf());
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<ABI::Windows::Foundation::Collections::IPropertySet> pProps;
hr = pSet.As(&pProps);
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<ABI::Windows::Foundation::Collections::IMap<HSTRING, IInspectable *>> spSetting;
hr = pSet.As(&spSetting);
if (FAILED(hr)) return hr;
hr = Windows::Foundation::GetActivationFactory(Microsoft::WRL::Wrappers::HStringReference
    (RuntimeClass_Windows_Foundation_PropertyValue).Get(), objFactory.ReleaseAndGetAddressOf());
if (FAILED(hr)) return hr;
Microsoft::WRL::ComPtr<ABI::Windows::Foundation::IPropertyValueStatics> spPropVal;
hr = objFactory.As(&spPropVal);
if (FAILED(hr)) return hr;
hr = imedPrevCap->StartPreviewToCustomSinkIdAsync(encProps.Get(), Microsoft::WRL::Wrappers::HStringReference
    (RuntimeClass_TimeStamp_WebCamSecExtensions_MediaSink).Get(), pProps.Get(), pAction);
//when finished
hr = imedPrevCap->StopPreviewAsync(pAction);
CComPtr<IMFTopologyNode> pNode; // Create the node.
HRESULT hr = MFCreateTopologyNode(MF_TOPOLOGY_OUTPUT_NODE, &pNode);
if (SUCCEEDED(hr)) {
CComPtr<IMFMediaSink> pSink;
hr = TimeStamp::WebCamSecExtensions::MediaSink::CreateInstance<IMFMediaSink>(&pSink);
if (FAILED(hr)) return hr;
CComPtr<IMFAttributes> pAttr;
hr = pSink->QueryInterface(&pAttr);
if (FAILED(hr)) return hr;
CComPtr<IMFMediaTypeHandler> pHandler; hr = pSD->GetMediaTypeHandler(&pHandler);
if (FAILED(hr)) return hr;
CComPtr<IMFMediaType> pMediaType;
hr = pHandler->GetCurrentMediaType(&pMediaType);
if (FAILED(hr)) return hr;
hr = pAttr->SetUnknown(MF_MEDIASINK_PREFERREDTYPE, pMediaType.Detach());
if (FAILED(hr)) return hr;
hr = pNode->SetObject(pSink);

Points of Interest

Passing parameters is done through a PropertyBag in WinRT/WRL yet through the IMFAttribute interface in non-WinRT/non-WRL code which can be found through IUnknown QueryInterface on the Custom Sink object.

An object of type ICustomSinkCallback must be passed and the interface implemented to utilize the features including initialization, cleanup, property change notification, preparing for samples and sample processing.

When initializing the custom sink, if planning to reuse the MediaCapture object, then be sure to pass the activation name to StartPreviewToCustomSinkAsync and not an instance of a CustomSink object. There is a bug in the MediaCapture library which causes it to become in a bad state if not using the activation ID which is present in Windows 8 and Windows 8.1.

The code is compatible with Visual Studio 2012/2013/2015 and Windows 8/8.1/10.


  • Initial version


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Gregory Morse
Software Developer (Senior)
United States United States
No Biography provided

Comments and Discussions

QuestionMy Previous Post Pin
Eitan Barazani31-Oct-14 6:11
MemberEitan Barazani31-Oct-14 6:11 
QuestionReading RAW video stream from a Windows Phone/Tablet camera (in WinRT) Pin
Eitan Barazani29-Oct-14 9:25
MemberEitan Barazani29-Oct-14 9:25 
AnswerRe: Reading RAW video stream from a Windows Phone/Tablet camera (in WinRT) Pin
Gregory Morse29-Oct-14 10:34
MemberGregory Morse29-Oct-14 10:34 
This could be done. The project really needs a DLL wrapper as utilizing WinRT from straight C++ or even C++/CX or both even is a specialty not something for most. However most people would want to customize the C++ part of the code for example in my usage to add a timestamp or due some useful processing like motion detection. Dealing with the frames here in the capturing thread is far better than any other option. The wrapper will still be a great starting point for that as well though. Also, I have tested on Windows Phone and it indeed does work.

I have such a DLL wrapper for my own projects that I will try to adapt for this as I realize for most people such a block of code would be far more useful if it could be dropped into a JavaScript or C# WinRT project and used with a few lines of code. The problem is that the context makes the wrapper for this code potentially different in each case so it is hard for me to provide a great generic solution. My context was motion detection and time stamping so obviously the processing was done in C++ and only a notification message with an occasional frame would be transferred to the UI. I will try when I have free time to make a pattern that would handle customization and even transfer to UI thread situations. Since special care needs to be taken to handle UI threads, that bit of code although short is quite critical to be implemented properly.
GeneralRe: Reading RAW video stream from a Windows Phone/Tablet camera (in WinRT) Pin
Eitan Barazani29-Oct-14 11:25
MemberEitan Barazani29-Oct-14 11:25 
QuestionIs FTM a must have? Pin
zxli6-Jun-14 19:12
Memberzxli6-Jun-14 19:12 
AnswerRe: Is FTM a must have? Pin
Gregory Morse8-Jun-14 0:18
MemberGregory Morse8-Jun-14 0:18 
QuestionIs this something I would need given my requirement? Pin
Steven123456789026-May-14 8:56
MemberSteven123456789026-May-14 8:56 
AnswerRe: Is this something I would need given my requirement? Pin
Gregory Morse26-May-14 12:47
MemberGregory Morse26-May-14 12:47 
QuestionThis is really helpful... Pin
zxli20-May-14 13:13
Memberzxli20-May-14 13:13 
AnswerRe: This is really helpful... Pin
Gregory Morse20-May-14 16:07
MemberGregory Morse20-May-14 16:07 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.