Windows offers an API to applications to change the endpoint volume.
If the driver offers a KSPROPERTY_AUDIO_VOLUMELEVEL node, the API will be
connected to this node.
If the driver does not, Windows will insert a software volume APO.
https://msdn.microsoft.com/en-us/library/windows/hardware/ff536251(v=vs.85).aspx
From: Alexander Ivash<mailto:elderorb@xxxxxxxxx>
Sent: Thursday, August 11, 2016 3:18 PM
To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
Subject: [wdmaudiodev] AVStream virtual mic: why could external application
'reset' volume level to 100%?
For some reasons it happens with virtual mic, but everything looks
fine with real one, what could be the difference?
Another observation, real mic's volume level changes from "+40dB" to
"+60dB" in Win10, while virtual mic changes from "0" to "100". Is it
because I didn't specify 'volume' node in topology or something like
this?
Regards, Alexander
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