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Operational Correspondence with Motion Compensation Device Driver

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[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

This section contains a description of the Motion Compensation device driver side of the DirectX VA interface. (Reference:Windows 2000 DDK - Graphics Drivers - Design Guide - 3.0 DirectDraw DDI - 3.12 Motion Compensation. See the Windows DDK for documentation on the structures in boldface.)

The following items refer to entries accessed through the DD_MOTIONCOMPCALLBACKS structure:

  1. At the start of the relevant processing, the device driver's DdMoCompCreate is used to notify the driver that the software decoder will start using a video acceleration object.
  2. GUIDs received from IAMVideoAccelerator::GetVideoAcceleratorGUIDs originate from the device driver's DdMoCompGetGUIDs.
  3. A call to the downstream input pin's IAMVideoAccelerator::GetUncompFormatsSupported returns data from the device driver's DdMoCompGetFormats.
  4. The DXVA_ConnectMode data structure from the decoder's IAMVideoAcceleratorNotify::GetCreateVideoAcceleratorData is passed to the device driver's DdMoCompCreate.
  5. Data returned from IAMVideoAccelerator::GetCompBufferInfo originates from the device driver's DdMoCompGetBuffInfo.
  6. Buffers sent using IAMVideoAccelerator::Execute are received by the device driver's DdMoCompRender.
  7. Use of IAMVideoAccelerator::QueryRenderStatus invokes the device driver's DdMoCompQueryStatus. A return code of DDERR_WASSTILLDRAWING from DdMoCompQueryStatus will be seen by the host decoder as a return code of E_PENDING from IAMVideoAccelerator::QueryRenderStatus.
  8. Data sent to IAMVideoAccelerator::BeginFrame are received by the device driver's DdMoCompBeginFrame. A return code of E_PENDING is needed from DdMoCompBeginFrame in order for E_PENDING to be seen by the host decoder in response to IAMVideoAccelerator::BeginFrame.
  9. Data sent to IAMVideoAccelerator::EndFrame are received by the device driver's DdMoCompEndFrame.
  10. At the end of the relevant processing, the device driver's DdMoCompDestroy is used to notify the driver that the current video acceleration object will no longer be used, so that the driver can perform any necessary cleanup.