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Vista/Win7 appear to persist the sound level settings per application. I'd like to have a look at that list.
The reason? According to a Microsoft blog, the settings are stored against the PID of the application, and I'd really like to find out what that PID is. I'm having trouble isolating which process is 'registering' itself with the Volume Mixer.
His Royal Redness
Posted 2011-05-17T04:16:45.557
Reputation: 313
10
Windows 7 does persist the audio settings for applications in the registry:
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\LowRegistry\Audio\PolicyConfig\PropertyStore
There are lots of sub-keys with numeric names. The settings are indexed by full application path so search for the name of your application in there.
I needed to find this because my Media Player Classic suddenly stopped producing any sound, and in a way which I figured couldn't be caused by a mis-configuration on my side. Finding a key containing mplayerc.exe and deleting it fixed the problem.
SnakE
Posted 2011-05-17T04:16:45.557
Reputation: 279
thank you for this. I muted one of my games, and exited it. Then when I restarted the game I could not umute it with windows volume mixer since it did not show up. Deleting the keys here for my game fixed the issue. – protoss1210 – 2015-10-19T08:19:34.333
Now for the next question: Which registry cleaner will clean these for me? I got around 1 MB of registry bloat there. – Zero3 – 2016-01-05T22:48:02.110
1SnakE, you da man! I fiddled with the volume settings on an app, and did notice some change to the sub key that 'seemed' to correspond in a meaningful way. There's still some work to do to interpret what the values mean, but at least I know where they're stored. The '3' key seems to store the volume setting, and the '5' key toggles between a 00 and ff when that app's volume is muted. I'm sure that some experimentation will reveal further details. – His Royal Redness – 2011-06-14T04:32:51.060
5That is one of the most absurd registry paths I've ever seen. And to think that I tried to find it by thinking logically where I'd put it in, before looking here for the answer... – Daniel Saner – 2013-04-29T02:27:46.280
0
The PID is the Process ID Number, a semi-random* number assigned to a process when it is created. You can see the process ID of a running process in the Task Manager or pretty much any other program that lists running programs.
The process ID number has no significance outside of being the unique identifier for a given process.
Since PID's don't persist across reboots, etc. I would imagine that the Mixer is storing them in memory.
*Not actually random, but also not generated in any meaningful pattern. Numbers are generally, but not necessarily, assigned in numeric order and in all versions of Windows NT, at least, are multiples of 4.
Andrew Lambert
Posted 2011-05-17T04:16:45.557
Reputation: 7 136
Yup, I get all that about PIDs. If I'm able to find the PID of the slider in the Volume Mixer, I can find the app thats related to it (using Task Manager, PowerShell, whatever). The link in my question says the persisted settings are keyed by PID. Although it's not official reference material, I think the author lends it some weight – His Royal Redness – 2011-05-19T04:07:30.317
The linked article makes no mention of persisted settings. All it says is that the Volume Mixer retains for a period of time the PID of a program that makes a sound. It uses the PID to find the name of the application; if the application exits before the Mixer does the lookup then it can't show the name. So, the mixer does not store anything aside from the PID and even then for only a brief period. Nothing is written out to disk (in the form of a Registry setting or some sort of config file) but is instead retained in memory only. Are you sure that volume settings persist across reboots? – Andrew Lambert – 2011-05-19T18:23:36.837
2Hmm, I’m fairly sure that I’ve seen the volume settings retained days later when I ran the same program again. – Synetech – 2011-06-14T03:06:02.673
1Yes, I am absolutely certain that volume settings are persisted across reboots. That's what makes the individual settings useful. Else, why bother? – His Royal Redness – 2011-06-14T04:31:02.387
Since the PID for an app will be different between reboots (or even if you close/open it), it's absolutely NO use in storing settings for later use. It may well use the PID while the mixer is running but as described in another answer, it seems to store it against executable name/path – Basic – 2012-01-04T10:04:59.437
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For anyone looking to fix the bug where Windows "forgets" the individual volume settings of applications, look at the accepted answer to this question (it's marked as a duplicate but isn't, really, imho).
– Amos M. Carpenter – 2014-11-15T10:16:23.130