Disable PulseAudio flat volumes to prevent it from pushing volume level to max

[kendell clark]

hi
Yup, I've seen all these use cases. TBH, this really should be handled
in pulse audio. IE this isn't so much a problem of gnome, although I do
agree taht they should make app volumes easier to set, as it is a pulse
audio problem. Pulse audio should be smart enough to handle such use
cases and adjust for them. In particular, the case where you adjust the
master volume and then adjust an application's volume downward. You're
correct, the system volume doesn't compensate. I thought this was a
problem with speech-dispatcher, since being blind I depend on it nearly
constantly to hear speech, but it apparently isn't limited to a single
application.
Thanks
Kendell clark


On 09/21/2015 05:41 AM, Kamil Paral wrote:
>> Today I had a scary experience with the audio of my computer.
>> I was listening to music with Amarok, using my headphones... The KMix volume
>> level was ~ 35%. When I logged into a video conference application, the
>> volume suddenly reached the 100%. I was shocked, having the maximum audio
>> level shooted in your ears is a painful experience.
>> The conference application that triggered PulseAudio pushing volume to
>> maximum level probably should have never asked the system for a 100% audio
>> level, but on the other hand, PulseAudio should never allow an application
>> to make such sudden changes.
>> To avoid that, you have to set
>> flat-volumes = no
>> in /etc/pulse/daemon.conf
> 
> I disable flat volumes on every computer that I own. In my experience there are too many applications that interact with it improperly, and having the master volume raised suddenly can be extremely unpleasant. It's naive to think that all apps will behave and will not contain any bugs. The system should not allow the apps to physically hurt the user just because of bugs or improper implementation. Flat volumes allow exactly that.
> 
> A colleague of mine experienced music volume bursts every time Pidgin played a notification. No amount of fiddling with Pidgin settings seemed to be able to fix that. I recommended him to disable flat volumes and the problem was of course gone. And this is Pidgin, one of the most prominent IM apps in the Linux world. What about third-party apps, how can we expect them to behave?
> 
> The problem is not related just to increasing the volume suddenly. There are other confusing and annoying use cases. If you have a game without a volume slider (think of something along the lines of Extreme Tux Racer) and you want to temporarily increase other volume source (let's say a youtube video, or a skype), if you raise the volume, it makes it at the expense of the other apps. So your game is now at e.g. 30% of the master volume (that value is remembered and applied for future app executions as well). The end result is that after you finish e.g. calling with someone and switch back to the game, it's suddenly way too silent, no matter how much you turn the knob of the master volume (and if you crank it fully up, sounds from other apps might pierce your ear drums). Closing and starting the game again doesn't help. The only way to fix this is to go to deeply buried sound settings in gnome control center and adjust your app's slider. Hardly discoverable for a standard user. And 
 y
ou need to do this every time such a use case happens. If GNOME implemented a slider for every playing application in the user menu [1], this wouldn't be so bad, but it doesn't.
> 
> Another confusing use case is when you have temporarily increase the volume too much and quickly drag it down (let's say you have rhythmbox playing and you increase the volume to 100% percent by accident, then lower it down immediately). When you turned the app volume up, the master volume went up (let's say it's 100% now). When you turned it down, only the app volume went down, the master volume stayed at 100%. So when you run a different app and it emits some sounds, it's going to blast your ears off, without warning.
> 
> Overall I think the flat volumes idea might be appealing in theory, but breaks hard in a number of not-so-edge cases, which unfortunately are not that rare as they might have seemed to PA developers. Also, these cases either result in an annoyance ("the volume is too low and I don't see how to fix it") or even a physical attack (if an OS allows to blast 100% volume into my headphones even for regular, non-malicious apps, just because of "missing implementation", I won't be using that OS for long). The impact of these "bugs" is simply too high. I'd love to see flat volumes disabled by default.
> 
> [1] https://extensions.gnome.org/extension/858/volume-mixer/
>