I have build custom SIP/RTP softphone which uses WASAPI for audio input / output. Windows 10 is lowering other audio streams volume when call comes and restores it back when call is finished. I know this is called "stream-attenuation" or "audio ducking" according to MSDN.
However all of this works only on communication device; the volume is not lowered on another audio devices which play background audio in this moment.
MSDN does not explain this explicitly and I don't understand. Is it normal behavior ? Or audio streams volume should be lowered on all other audio devices as well ?
Thank you very much !