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Editorial Team
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Asked: 2026-05-12T05:28:23+00:00

Does anyone know how to get the current volume level of an audio session*

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Does anyone know how to get the current volume level of an audio session* in Vista or 7?

I’ve got the IAudioSessionControl2 and IAudioSessionManager2 instances you need to listen for volume changes, but actually getting the current volume is proving elusive.

*by audio session I mean (roughly) the per-application audio control, not the “master” one

Note that (so far as I can tell) IAudioSessionManager2->GetSimpleVolume() isn’t the right answer here. The only thing that publishes a GUID in IAudioSessionControl2 is the Grouping parameter, and using it in GetSimpleVolume creates new sessions rather than giving you the control for an existing one.

GetSimpleVolume() is what I want, but where are the params coming from in this setup?

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  1. Editorial Team

    Actually IAudioSessionManager::GetSimpleAudioVolume IS what you’re looking for.

    An audio session is identified by two (or three) things: The session guid, the process ID and the cross process flag (if the cross process flag is specified when the stream is created, the process ID is ignored).

    The simple audio volume controls the volume of all the streams within that audio session. It’s fairly straightforward (most rendering frameworks specify NULL for the session GUID). If your application uses a specific session GUID, you should just specify the session GUID your application is using.

    There’s one other twist though. The volume control (sndvol.exe) combines all sessions with the same “grouping param” together in the UI – this isn’t a part of the volume control, it’s a UI convenience feature that exists only for web browsers like IE – it exists to allow 3rd party audio frameworks (which specify a GUID_NULL session GUID) and the WMP OCX (which specifies a cross process session with a specific session GUID) to share a single slider in the volume UI.

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