CBaseStreamControl::CheckStreamState

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

Retrieves a stream's current state.

Syntax

enum StreamControlState CheckStreamState( 
  IMediaSample* pSample
);

Parameters

• pSample
  Pointer to an IMediaSample interface.

Return Value

Returns a StreamControlState enumeration type.

Remarks

Your filter calls this member function when your pin receives a sample that it is about to forward. The first sample you forward after throwing one or more away should be marked as a discontinuity.

The following example shows what you should include if your filter inherits from CBaseStreamControl.

//Pin has been given a sample to pass on, pSample
//m_fLastSampleDiscarded is initialized to TRUE when streaming starts
int iStreamState = CheckStreamState(pSample);
if (iStreamState == STREAM_FLOWING) {
   if (m_fLastSampleDiscarded)
      pSample->SetDiscontinuity(TRUE);
   m_fLastSampleDiscarded = FALSE;
   //now deliver it or put it o a queue to be delivered, or whatever.
} else {
   m_fLastSampleDiscarded = TRUE;     //next one is discontinuity
   //Do NOT deliver this sample. Just throw it away.
}

Requirements