播放时更改音频渲染器端点

Question

I'm writing an audio player using Microsoft Media Foundation. I wonder is it possible to change the playback device without re-creating the session?

IMFActivate *m_p_sink_activate;
...
m_p_sink_activate->SetString(MF_AUDIO_RENDERER_ATTRIBUTE_ENDPOINT_ID, name_device);

This doesn't take effect if the audio is already being played.

Btw, the media player provided by Microsoft.Windows.SDK.Contracts (Windows.Media.Playback.MediaPlayer) does it perfectly. When I change m_mediaPlayer.AudioDevice, the audio stream is redirected to the assigned device immediately. So I wonder if this is also possible for MSMF.

Answer 1

So far I have a way could do this job,

1. Create a new topology which cloned from previous one.
2. Create new audio renderer using MFCreateAudioRendererActivate and using set string with the new audio endpoint ID add it to a topologynode;
3. Add the new node to new topology;
4. Using IMFMediaSession::SetTopology() do set new topology to play.

You could refer to MS sample TopoEdit for detail.

One side effect is that each time SetTopology cause huge memory growth.