https://learn.microsoft.com/en-us/windows/win32/api/endpointvolume/nf-endpointvolume-iaudioendpointvolume-getchannelcount
IAudioEndpointVolume::GetChannelCount (endpointvolume.h) - Win32 apps | Microsoft Learn
The GetChannelCount method gets a count of the channels in the audio stream that enters or leaves the audio endpoint device.
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