[vlc] Re: Live Streaming

[Bill Eldridge]

Alexis de Lattre wrote:

>On Tue, Aug 05, 2003, Mathew, Tisson K wrote :
>  
>
>>Does VLC support live video streaming on windows? 
>>    
>>
>
>No... this feature is "Linux only", as explained on
>
>http://www.videolan.org/vlc/features.html
>
>We would love to have a "Direct Show" input for VLC... but no developer
>have volunteered for this work.
>
>  
>
Here's some DirectX 8.1 code off codeguru from which someone could hack
out the video device part. I don't know anything about various issues
that would make this unworkable or way too primitive to be usable.


Relevant Functions:
CPreviewMovieDlg::GetDeviceInterfaces()
CPreviewMovieDlg::FindCaptureDevice(IBaseFilter** ppBaseFilter)
CPreviewMovieDlg::CaptureVideo()
CPreviewMovieDlg::CloseInterfaces()


http://www.codeguru.com/directx/DirectXApp.html

Excerpt:
===============================================
BOOL CPreviewMovieDlg::OnInitDialog()
{
        CDialog::OnInitDialog();

        HRESULT hr;
        hr = CaptureVideo();
        if(FAILED(hr))
        {
        CloseInterfaces();
            OnOK();
        }

        return TRUE;
}
HRESULT CPreviewMovieDlg::CaptureVideo()
{
        HRESULT         hr;
        IBaseFilter *pBaseFilter = NULL;

        //Get DirectShow Interfaces
        hr = GetDeviceInterfaces();
        if(FAILED(hr))
        {
                TRACE1(("Could not initialize the video interfaces!  
hr=0x%x"), hr);
                return hr;
        }

    // Attach the filter graph to the capture graph
        hr = m_pCaptureGraphBuilder->SetFiltergraph(m_pGraphBuilder);
        if(FAILED(hr))
        {
                TRACE1(("Could not set the filter graph to capture 
graph!  hr=0x%x"), hr);
                return hr;
        }

    // Add our graph to the running object table, which will allow
    // the GraphEdit application to "spy" on our graph
#ifdef REGISTER_FILTERGRAPH
    hr = AddGraphToRot(m_pGraphBuilder, &m_dwGraphRegister);
    if (FAILED(hr))
    {
        TRACE1(TEXT("Failed to register filter graph with ROT!  
hr=0x%x"), hr);
        m_dwGraphRegister = 0;
    }
#endif

    // Use the system device enumerator and class enumerator to find
    // a video capture/preview device, such as a desktop USB video camera.
        hr = FindCaptureDevice(&pBaseFilter);
        if(FAILED(hr))
        {
                return hr;
        }
   
        // Add Capture filter to our graph.
        hr = m_pGraphBuilder->AddFilter(pBaseFilter, L"Video Capture");
        if(FAILED(hr))
        {
        TRACE1(TEXT("Couldn't add capture filter to graph!  hr=0x%x"), hr);
        pBaseFilter->Release();
                return hr;
        }

        hr = m_pCaptureGraphBuilder->RenderStream(&PIN_CATEGORY_PREVIEW,
                                        &MEDIATYPE_Video, pBaseFilter, 
NULL, NULL);
    if (FAILED(hr))
    {
        TRACE1(TEXT("Couldn't render capture stream.  "
                 "The device may already be in use.\r\n\r\nhr=0x%x"), hr);

        pBaseFilter->Release();
        return hr;
        }

    // Now that the filter has been added to the graph and we have
    // rendered its stream, we can release this reference to the filter.
    pBaseFilter->Release();

    // Set video window style and position
        hr = SetupVideoWindow();
    if (FAILED(hr))
    {
        TRACE1(TEXT("Couldn't initialize video window!  hr=0x%x"), hr);
        return hr;
    }

    // Start previewing video data
        hr = m_pMediaControl->Run();
        if(FAILED(hr))
        {
        TRACE1(TEXT("Couldn't run the graph!  hr=0x%x"), hr);
        return hr;
        }

        return S_OK;
}

HRESULT CPreviewMovieDlg::GetDeviceInterfaces()
{
        HRESULT hr;

        //Create the filter graph
        hr = CoCreateInstance (CLSID_FilterGraph, NULL, CLSCTX_INPROC,
                IID_IGraphBuilder, (void **)&m_pGraphBuilder);

        if(FAILED(hr))
                return hr;

        //Create the Capture graph
        hr = CoCreateInstance (CLSID_CaptureGraphBuilder2, NULL, 
CLSCTX_INPROC,
                IID_ICaptureGraphBuilder2, (void 
**)&m_pCaptureGraphBuilder);

        if(FAILED(hr))
                return hr;

        //Obtain the interfaces for media control, video and media event 
interfaces
        hr = m_pGraphBuilder->QueryInterface (IID_IMediaControl, (void 
**)&m_pMediaControl);

        if(FAILED(hr))
                return hr;

        hr = m_pGraphBuilder->QueryInterface (IID_IVideoWindow, (void 
**)&m_pViewWindow);

        if(FAILED(hr))
                return hr;

        hr = m_pGraphBuilder->QueryInterface (IID_IMediaEvent, (void 
**)&m_pMediaEventEx);

        if(FAILED(hr))
                return hr;

        //Set the window handle used to process graph events
        m_pMediaEventEx->SetNotifyWindow((OAHWND)m_hWnd, WM_GRAPHNOTIFY, 0);

        return hr;
}
HRESULT CPreviewMovieDlg::FindCaptureDevice(IBaseFilter** ppBaseFilter)
{
        IBaseFilter                     *pBase = NULL;
        HRESULT                         hr;
        CComPtr <IMoniker>      pMoniker = NULL;
        ULONG                           lFetched;

    // Create the system device enumerator
        CComPtr <ICreateDevEnum> pDevEnum = NULL;

        hr = CoCreateInstance (CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC,
                IID_ICreateDevEnum, (void **)&pDevEnum);

        if(FAILED(hr))
        {
                TRACE1(("Failed to create the device enumerator!  
hr=0x%x"), hr);
                return hr;
        }

    // Create an enumerator for the video capture devices
        CComPtr <IEnumMoniker> pClassEnum = NULL;

    hr = pDevEnum->CreateClassEnumerator 
(CLSID_VideoInputDeviceCategory, &pClassEnum, 0);

        if(FAILED(hr))
        {
                TRACE1(("Failed to create the class enumerator!  
hr=0x%x"), hr);
                return hr;
        }

    // If there are no enumerators for the requested type, then
    // CreateClassEnumerator will succeed, but pClassEnum will be NULL.
    if (pClassEnum == NULL)
    {
        MessageBox(TEXT("No video capture device was detected.\r\n\r\n")
                   TEXT("This program requires a video capture device, 
such as a USB WebCam,\r\n")
                   TEXT("to be installed and working properly.  The 
program will now close."),
                   TEXT("No Video Capture Hardware"), MB_OK | 
MB_ICONINFORMATION);
        return E_FAIL;
    }

    // Note that if the Next() call succeeds but there are no monikers,
    // it will return S_FALSE (which is not a failure).  Therefore, we
    // check that the return code is S_OK instead of using SUCCEEDED() 
macro.

    //loop while we can still enumerate, the enumeration succeeds, and 
while we have'nt yet found a dv camera
        while( (pClassEnum->Next(1, &pMoniker, &lFetched)) == S_OK)
        {
                // getting the propert page to get the device name
        IPropertyBag *pBag;
                hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag, 
reinterpret_cast<PVOID *>(&pBag));
        if ( SUCCEEDED(hr) )
        {
            VARIANT var;
            var.vt = VT_BSTR;
            hr = pBag->Read(L"FriendlyName", &var, NULL);
            if ( SUCCEEDED(hr) )
            {
                                CString strDevName;

                                USES_CONVERSION;
                                strDevName = W2A(var.bstrVal);

                                m_cboDevice.AddString(strDevName);

                                SysFreeString(var.bstrVal);

                                // Bind Moniker to a filter object
                                hr = pMoniker->BindToObject(0, 0, 
IID_IBaseFilter, reinterpret_cast<LPVOID *>(&pBase));
                            if (FAILED(hr))
                                {
                                        TRACE1(TEXT("Couldn't bind 
moniker to filter object!  hr=0x%x"), hr);
                                        return hr;
                                }
                        }
                        pBag->Release();
                }
        }

        *ppBaseFilter = pBase;

        return hr;
}



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