MFCreateSequencerSegmentOffset function (mfidl.h)

Creates a PROPVARIANT that can be used to seek within a sequencer source presentation.

Syntax

HRESULT MFCreateSequencerSegmentOffset(
 [in] MFSequencerElementId dwId,
 [in] MFTIME hnsOffset,
 [out] PROPVARIANT *pvarSegmentOffset
);

Parameters

[in] dwId

Sequencer element identifier. This value specifies the segment in which to begin playback. The element identifier is returned in the IMFSequencerSource::AppendTopology method.

[in] hnsOffset

Starting position within the segment, in 100-nanosecond units.

[out] pvarSegmentOffset

Pointer to a PROPVARIANT. The method fills in the PROPVARIANT with the information needed for performing a seek operation. The caller must free the PROPVARIANT by calling PropVariantClear.

Return value

If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

The PROPVARIANT returned in pvarSegmentOffset can be used for the pvarStartPosition parameter in the IMFMediaSession::Start method. Use the time format GUID MF_TIME_FORMAT_SEGMENT_OFFSET.

Examples

// Skips to the specified segment in the sequencer source

HRESULT CPlaylist::SkipTo(DWORD index)
{
 if (index >= m_count)
 {
 return E_INVALIDARG;
 }

 MFSequencerElementId ID = m_segments[index].SegmentID;

 PROPVARIANT var;

 HRESULT hr = MFCreateSequencerSegmentOffset(ID, NULL, &var);
 
 if (SUCCEEDED(hr))
 {
 hr = m_pSession->Start(&MF_TIME_FORMAT_SEGMENT_OFFSET, &var);
 PropVariantClear(&var);
 }
 return hr;
}

Requirements

See also

MFTIME

Media Foundation Functions

Sequencer Source

Using the Sequencer Source