directshow_audio_volume

Mix to mono

The filter is able to mix all channels to a mono channel. This feature can be configured by using the interface IAudioVolumeMix. Here is a short sample code for c++:

CComQIPtr<IAudioVolumeMix, &IID_IAudioVolumeMix> pAudioVolMix = m_pAudioVol;
if(pAudioVolMix)
{
   pAudioVolMix->MixToMono(true); // true==mix all channels to one
}
...

Note: that the option MixToMono has to be set before the output pin of the Audio Volume filter is connected to another filter.