IMFTopologyNode* MediaSource::CreateTopologySourceNode()
{
IMFTopologyNode* mfTopologyNode = nullptr;
IMFStreamDescriptor* mfStreamDescriptor = nullptr;
HRESULT hr;
DWORD streamDescriptorCount;
BOOL isSelected;
do
{
// Iterate through the source streams to find the currently selected one
if (!SUCCEEDED(hr = _mfPresentationDescriptor->GetStreamDescriptorCount(&streamDescriptorCount)))
break;
for (DWORD i = 0; i < streamDescriptorCount; i++)
{
if (!SUCCEEDED(hr = _mfPresentationDescriptor->GetStreamDescriptorByIndex(i, &isSelected, &mfStreamDescriptor)))
break;
if (isSelected)
{
break;
}
else
{
mfStreamDescriptor->Release();
mfStreamDescriptor = nullptr;
}
}
if (FAILED(hr) || !mfStreamDescriptor)
{
throw std::exception("Could not find selected stream in MediaSource");
}
// otherwise, we're in good shape :-)
if (!SUCCEEDED(hr = MFCreateTopologyNode(MF_TOPOLOGY_SOURCESTREAM_NODE, &mfTopologyNode)))
break;
if (!SUCCEEDED(hr = mfTopologyNode->SetUnknown(MF_TOPONODE_SOURCE, _mfMediaSource)))
break;
if (!SUCCEEDED(hr = mfTopologyNode->SetUnknown(MF_TOPONODE_PRESENTATION_DESCRIPTOR, _mfPresentationDescriptor)))
break;
if (!SUCCEEDED(hr = mfTopologyNode->SetUnknown(MF_TOPONODE_STREAM_DESCRIPTOR, mfStreamDescriptor)))
break;
} while (0);
if (FAILED(hr))
{
throw std::exception("Could not create topology source node");
}
mfStreamDescriptor->Release();
return mfTopologyNode;
}
/** Set playback topology */
FIntPoint FImfVideoPlayer::SetPlaybackTopology( FImfSampleGrabberCallback* SampleGrabberCallback )
{
FIntPoint OutDimensions = FIntPoint( ForceInit );
HRESULT HResult = S_OK;
IMFPresentationDescriptor* PresentationDesc = NULL;
HResult = MediaSource->CreatePresentationDescriptor( &PresentationDesc );
check( SUCCEEDED( HResult ) );
IMFTopology* Topology = NULL;
HResult = MFCreateTopology( &Topology );
check( SUCCEEDED( HResult ) );
DWORD StreamCount = 0;
HResult = PresentationDesc->GetStreamDescriptorCount( &StreamCount );
check( SUCCEEDED( HResult ) );
for( uint32 i = 0; i < StreamCount; i++ )
{
BOOL bSelected = 0;
IMFStreamDescriptor* StreamDesc = NULL;
HResult = PresentationDesc->GetStreamDescriptorByIndex( i, &bSelected, &StreamDesc );
check( SUCCEEDED( HResult ) );
if( bSelected )
{
FIntPoint VideoDimensions = AddStreamToTopology( Topology, PresentationDesc, StreamDesc, SampleGrabberCallback );
if( VideoDimensions != FIntPoint( ForceInit ) )
OutDimensions = VideoDimensions;
}
StreamDesc->Release( );
}
HResult = MediaSession->SetTopology( 0, Topology );
check( SUCCEEDED( HResult ) );
Topology->Release( );
PresentationDesc->Release( );
return OutDimensions;
}
