MFCreateVideoSampleFromSurface callback function (evr.h)

Artigo
12/05/2018

[The component described on this page, Enhanced Video Renderer, is a legacy feature. It has been superseded by the Simple Video Renderer (SVR) exposed through the MediaPlayer and IMFMediaEngine components. To play video content you should send data into one of these components and allow them to instantiate the new video renderer. These components have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer or the lower level IMFMediaEngine APIs to play video media in Windows instead of the EVR, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Creates a media sample that manages a Direct3D surface.

Syntax

MFCreateVideoSampleFromSurface Mfcreatevideosamplefromsurface;

EVRPUBLIC Mfcreatevideosamplefromsurface(
  [in]  IUnknown *pUnkSurface,
  [out] IMFSample **ppSample
)
{...}

Parameters

[in] pUnkSurface

A pointer to the IUnknown interface of the Direct3D surface. This parameter can be NULL.

[out] ppSample

Receives a pointer to the sample's IMFSample interface. The caller must release the interface.

Return value

If this callback function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

The media sample created by this function exposes the following interfaces in addition to IMFSample:

If pUnkSurface is non-NULL, the sample contains a single media buffer, which holds a pointer to the Direct3D surface. To get the Direct3D surface from the media buffer, call IMFGetService::GetService on the buffer, using the service identifier MR_BUFFER_SERVICE. The media buffer does not implement IMF2DBuffer, nor does it implement the IMFMediaBuffer::Lock and Unlock methods.

Alternatively, you can set pUnkSurface to NULL, and later add a DirectX surface buffer to the sample by calling IMFSample::AddBuffer. To create a DirectX surface buffer, call MFCreateDXSurfaceBuffer.

Examples

The following example is taken from the EVRPresenter Sample.

//-----------------------------------------------------------------------------
// CreateD3DSample
//
// Creates a sample object (IMFSample) to hold a Direct3D swap chain.
//-----------------------------------------------------------------------------

HRESULT D3DPresentEngine::CreateD3DSample(
    IDirect3DSwapChain9 *pSwapChain,
    IMFSample **ppVideoSample
    )
{
    // Caller holds the object lock.

    D3DCOLOR clrBlack = D3DCOLOR_ARGB(0xFF, 0x00, 0x00, 0x00);

    IDirect3DSurface9* pSurface = NULL;
    IMFSample* pSample = NULL;

    // Get the back buffer surface.
    HRESULT hr = pSwapChain->GetBackBuffer(
        0, D3DBACKBUFFER_TYPE_MONO, &pSurface);
    if (FAILED(hr))
    {
        goto done;
    }

    // Fill it with black.
    hr = m_pDevice->ColorFill(pSurface, NULL, clrBlack);
    if (FAILED(hr))
    {
        goto done;
    }

    // Create the sample.
    hr = MFCreateVideoSampleFromSurface(pSurface, &pSample);
    if (FAILED(hr))
    {
        goto done;
    }

    // Return the pointer to the caller.
    *ppVideoSample = pSample;
    (*ppVideoSample)->AddRef();

done:
    SafeRelease(&pSurface);
    SafeRelease(&pSample);
    return hr;
}

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	evr.h

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