IMediaTransform::QueryBufferRequirements method

Windows Movie Maker calls the QueryBufferRequirements method on startup to learn any special buffer requirements of the transform.

Syntax

HRESULT QueryBufferRequirements(
  [in]  DWORD        dwStream,
  [out] BufferFormat *pFormat
);

Parameters

dwStream [in]

One of the following DWORD values specifying an input or output stream:

0 indicates the output stream.

1 indicates the first input stream.

2 indicates the second input stream.

The transform should indicate the total number of input streams in its implementation of get_InputCount.

pFormat [out]

Pointer to a BufferFormat structure that specifies the format for that stream. The caller allocates this structure; the transform should fill it with the buffer requirements. For more information, see Remarks.

Return value

The method returns an HRESULT of S_OK for success, or a standard COM error code for failure.

Remarks

Most transforms will not have any special buffer requirements; unless your transform has special requirements, this method should return S_OK and not process the pFormat parameter that is passed in.

Requirements

See also

IMediaTransform Interface