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IMSVidPlayback::get_CanStep

  • 项目
 
Microsoft DirectShow 9.0

IMSVidPlayback::get_CanStep

This topic applies to Windows XP or later.

The get_CanStep method queries whether the input source can step frame by frame.

Syntax

  HRESULT get_CanStep(
  VARIANT_BOOL  fBackwards,
  VARIANT_BOOL *pfCan
);

Parameters

fBackwards

[in]  Use one of the following values.

Value Description
VARIANT_FALSE Query whether the input can step forward
VARIANT_TRUE Query whether the input can step backward.

pfCan

[out]  Pointer to a variable that receives one of the following values.

Value Description
VARIANT_FALSE The source cannot step in the specified direction.
VARIANT_TRUE The source can step in the specified direction.

Return Values

The method returns an HRESULT. Possible values include the following.

Value Description
E_POINTER NULL pointer argument.
ERROR_INVALID_STATE The graph is not built. Call the Build or View method on the Video Control.
S_OK The method succeeded.
  • Note   The value ERROR_INVALID_STATE is converted to an HRESULT with the HRESULT_FROM_WIN32 macro.

Remarks

Call the IMSVidCtl::Build or IMSVidCtl::View method before calling this method.

Example Code

VARIANT_BOOL fCan = VARIANT_FALSE;
hr = m_pPlayback->get_CanStep(VARIANT_FALSE, &fCan);

Requirements

  Header: Dshow.h.

  Library: Quartz.dll.

See Also