This method returns the number of DMA channels for a previously selected bit-stream type.

HRESULT GetDMAChannelCount(
  DWORD* pdwChannels


  • pdwChannels
    [out] Pointer to return the number of DMA channels available for current bit-stream type processing.

Return Values

The following table shows a list of possible return values.

Return value Description
S_OK The request completed successfully.
E_POINTER An invalid argument pointer has been encountered.
E_UNEXPECTED IBitstreamProcessor::SetBitstreamType did not succeed yet.


IBitstreamProcessor::SetBitstreamType should succeed before calling this method.

The navigator supports only one DMA channel for the DVD navigator. The renderer model was designed to expose other hardware rendering models that support multiple media stream; for example, audio/video in PES-level rendering with dual bus mastering. The actual number of exposed DMA channels, in general, is dependent on a bit-stream type set by IBitStreamProcessor::SetBitstreamType. The metarenderer will automatically provide a data port for every exposed DMA channel. For the DVD bit-stream type, this function is expected to return 1.


OS Versions: Windows CE .NET 4.0 and later.
Header: Dvddrvr.idl.

See Also

IBitstreamProcessor::SetBitstreamType | IBitstreamProcessor:IUnknown

 Last updated on Tuesday, May 18, 2004

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