380857 2017-06-05 08:58:35 +0000 Respect playback device output on systems with pulseaudio (flat-volumes = yes) 2017-06-06 12:37:48 +0000 1 1 3 Frameworks and Libraries phonon-backend-vlc general unspecified Gentoo Packages Linux RESOLVED DUPLICATE 345651 NOR normal --- 0 leonard sitter bcooksley fabo jb myriam plasma-bugs-null romain.perier 0 oldest_to_newest 1680647 0 leonard 2017-06-05 08:58:35 +0000 flat-volumes, which is enabled by default in PulseAudio (though many distributions disable it) scales the device-volume with the volume of the "loudest" application. Applications, unaware of this feature, can set their volume to 100% at startup, potentially blowing the speakers or ears of the user. Unfortunately KDE applications do exactly that, which is not only a health hazard for users but also relatively hard to debug for users unfamiliar with PulseAudio. KDE Applications should therefore at startup never set their output volume to 100%, but simply to the volume of the playback device to which they are outputting. I noticed this behaviour in particular with the error messages generated by Dolphin and Okular, but it probably affects more applications. Related bugs are #346614, #352312, #352176 and #327723 1680859 1 sitter 2017-06-06 11:31:07 +0000 Which phonon backend are you using? 1680863 2 leonard 2017-06-06 11:49:42 +0000 The package is currently build with the following USE flags (gentoo): ➜ ~ equery uses phonon [ Legend : U - final flag setting for installation] [ : I - package is installed with flag ] [ Colors : set, unset ] * Found these USE flags for media-libs/phonon-4.9.1-r1: U I - - abi_x86_32 : 32-bit (x86) libraries - - debug : Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces + - designer : Install plugin for dev-qt/designer - - gstreamer : Add support for media-libs/gstreamer (Streaming media) + + pulseaudio : Add support for PulseAudio sound server + + qt4 : Add support for the Qt GUI/Application Toolkit version 4.x + + qt5 : Add support for the Qt 5 application and UI framework + - vlc : Install VLC Phonon backend I.e. if I understand correctly it should use the pulseaudio backend. https://packages.gentoo.org/packages/media-libs/phonon 1680864 3 sitter 2017-06-06 11:56:04 +0000 Run `kcmshell5 phonon` go to the backend tab. What's the first backend in the list? 1680869 4 leonard 2017-06-06 12:05:46 +0000 Thanks for the clarification. It turns out only the vlc backend is listed there.. 1680877 5 sitter 2017-06-06 12:37:48 +0000 The problem is that the vlc backend right now creates all PA streams as category=video (or rather libvlc does and currently has no way to change that), which results in the stream getting a default volume (100%) which combined with flat volumes pushes everything up. If vlc could set category=notification it would get the default volume inherited from the global notification volume as seen in plasma-pa or pavucontrol rather than max volume. This is fixed in vlc master (to be vlc 3) and phonon-vlc master. Unfortunately, until that gets released we cannot do much about this. As far as specific applications (i.e. not notifications) are concerned you'll have to file bugs against the specific applications. If an application wants to explicitly set the volume to 100% that is the application's business. *** This bug has been marked as a duplicate of bug 345651 ***