CSourceSeeking.ChangeStart method
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The ChangeStart
method is called when the start position changes.
Syntax
virtual HRESULT ChangeStart() = 0;
Parameters
This method has no parameters.
Return value
Returns an HRESULT value.
Remarks
The CSourceSeeking::SetPositions method calls this method if the start position changes. This method is pure virtual; the derived class must implement it. After a seek operation, time stamps should restart from zero. Media times should reflect the new start time. The following example shows a possible implementation:
HRESULT CMyStream::ChangeStart( )
{
m_rtSampleTime = 0; // Reset the time stamps.
m_rtMediaTime = m_rtStart; // Reset the media times.
UpdateFromSeek();
return S_OK;
}
Requirements
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