This method sets the preroll property. If TRUE, this sample is for preroll only and should not be displayed.

HRESULT SetPreroll(
  BOOL bIsPreroll


  • bIsPreroll
    [in] Set to TRUE to specify the media sample as a preroll sample; otherwise, set to FALSE.

Return Values

Returns an HRESULT value that depends on the implementation. HRESULT can be one of the following standard constants, or other values not listed.

Value Description
E_FAIL Failure.
E_POINTER Null pointer argument.
E_INVALIDARG Invalid argument.
E_NOTIMPL Method is not supported.
S_OK or NOERROR Success.


Preroll samples are samples that are processed but not displayed, and are located in the media stream before the displayable samples.

While calling SetPreroll with a value of TRUE (1) sets the preroll property, calling IsPreroll on a preroll sample returns S_OK (0).


DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.

See Also

IMediaSample Interface

Last updated on Wednesday, April 13, 2005

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