Multiple input MFT in Microsoft Media Foundation

Question

I'm struggling with mixing two audio streams into single output stream. MFNode has an AudioMixerMFT but TopoEdit crashes when I try to build a topology like this & execute it:

Note: I tried TopoEdit that comes with Windows SDK 7.1 & also the one with few fixes by the author of "Developing Microsoft® Media Foundation Applications"

I thought it could be some issue with TopoEdit so I built the Topology in code (by modifying the code from Ch#9 of "Developing Microsoft® Media Foundation Applications") but it still failed with 'E_UNEXPECTED Catastrophic failure' on mediaEvent->GetStatus(&hrStatus) inside HRESULT CPlayer::ProcessEvent(CComPtr<IMFMediaEvent>& mediaEvent) on Session Start event.

Now at this point I thought it could be some issue with AudioMixerMFT so I wrote a Custom MFT with 2 inputs that acts like a simple pass-through (Only sends 1st input & ignores 2nd one). And I built a topology in TopoEdit like and it worked:

But when I connected 'Audio 2.wav' to MFT, it crashed. Now I tried to use this custom MFT in my own code & it worked again with single input but failed with 'E_UNEXPECTED Catastrophic failure' when applied two inputs.

Not sure what could be the problem, I started to doubt if multiple input MFT is supported, I came across a post http://social.msdn.microsoft.com/Forums/windowsdesktop/en-US/21596e11-c4e2-480a-b28f-9e2f5fa8820d/mutlinput-and-multioutput (yes it is quite old) that says it is not supported.

Is there anyone out there who was able to run AudioMixerMFT from MFNode successfully? Any alternates to Microsoft Media Foundation? or Any hint would be appreciated. Thanks

Answer 1

MFNode is my open source project.

If you read the MFNode's documentation, you will see that TopoEdit does not handle more than one inputstream in a MFT. And yes TopoEdit crashes. You can fix the bug in TopoEdit source code. It is just a null pointer that TopoEdit does not checked. But unfortunatly, it does not solve the problem. TopoEdit is not able to call ProcessInput twice on the two input streams, before calling ProcessOutput.

You have to provide a custom media session to make it work (implement IMFMediaSession).

In a next update of MFNode Project, i will provide a player to use all the MFNode, and especially the MFNode Audio Mixer.

EDIT: in tededit.cpp, TopoEdit crashes at CTedEditorVisualObjectEventHandler::NotifyObjectDeleted :

... CTedTopologyNode* pNode = m_pEditor->FindNode(pConn->GetOutputNodeID()); ...

pNode can be null pointer and TopoEdit does not check.

EDIT

I've updated my project. Check MFNodePlayer. I use a custom MediaSession to handle the wave mixer topology.

It works well but it is not perfect because of two things. If you stop the topo and then replay, it fails (because i must stop all source, and perhaps reset the time clock and bytestream). Second, there is a function wich handles IMFTransform in a recursive way. It is hard to debug.

I will fix later.

PS : Special thanks to "Developing Microsoft Media Foundation Applications" book. It helps me a lot to create a custom MediaSession.