Modify audio output device system/master volume on Windows

[zebranine]

Feature request

First post here so congratulations and thanks for this awesome offering.

It seems that volume commands from MPD clients (MALP, MPDCtrl) influence only the MPD output volume and not the output device's system/master volume level on the Windows host machine. If there is a way to do this I have not found it.

Since we are using the MPD server machine as an HTPC, the device volume may be left at an arbitrarily low level by the last user and this then caps the output from MPD. Only a manual adjustment of the device volume via the usual Windows controls resolves the issue.

I have various workarounds but direct setting of the Windows device volume by MPD would be ideal.

Thanks for your time.

[MaxKellermann]

I don't understand what you are doing, partly because you did not say anything about your setup, and partly because I have never used Windows, and I don't know what "system/master volume" is.

[zebranine]

I have a Windows 11 PC hosting MPD as a service, various clients (Windows, Android).

Client volume changes seem to modify only the MPD application volume, rather than the host audio device volume at the operating system level.

This means that if the Windows audio device used by MPD is set at 25% volume (in the Windows mixer), MPD can only reach maximum 25% of potential system volume even when it is set internally to 100% volume.

The OS mixer volume overrides the MPD application volume. This could be overcome if MPD set the Windows mixer level for the audio device directly.

Screenshot of client displaying MPD vol vs OS audio device vol:

[zebranine]

Found a partial solution.

MPD will control Windows Mixer master volume if mpd.conf audio_output settings specify the following:

type "wasapi"
exclusive "yes"

This, however, means no other programs can use the audio device, so not ideal.

[bigboipete]

If I get your description right, the observed behavior makes totally sense to me:

If you transfer it to the analogue world, see it as a chain of two volume knobs. First is the player and second (aka closest to the audio output) is the Windows mixer. If you set the second/last volume in the chain down to 25% you can crank the first volume as much as you want, you are always limited by the second volume.

From an audio-chain perspective this is reasonable, because a "volume knob" should modify volume for the respective device/player it "belongs" to and not touch any master volume. It's up to the user to bring these two volumes in a balance to preserve headroom for the player's (aka first) "volume knob".

But in software you can certainly wire any setup, that's desired.

[zebranine]

I certainly don't say the behaviour is wrong but rather that this is a use case specific scenario where more than one configuration is desirable.

In our case the device is used for multiple purposes but only ever one at a time so it makes sense for individual applications to operate at 'full' volume and simplify the control of volume (via various remotes) to alter only the master volume.