[Pkg-pulseaudio-devel] Bug#541538: Sound volume jumps on play

[Ulrich Eckhardt]

Package: pulseaudio
Version: 0.9.15-4.1

I'm pressing play on Amarok and the volume of the output device jumps up. What 
I had was that I had the volume at around 70%. I then pressed play and the 
volume displayed by 'pavucontrol' jumped to 120%. Yes, it indeed jumped to a 
value beyond 100% which I can not otherwise set. I was able to turn it down 
again, but hitting stop and start again turned up the volume beyond what I 
usually like. I guess my neighbors weren't amused either, at 7AM. Well, at 
least I saved making coffee, because I was then Wide Friggin' Awake(tm).

Now, further observations:
1. When started, the volume sliders of the output device and the sound source 
seem to be synced, i.e. moving one also moves the others. Those used to be 
separate. Note that other applications like xine also exhibit such behavior.
3. Amarok's internal volume slider still works, I can still use it to turn 
down the music. I guess it uses an internal software mixer to scale the output 
stream.
4. The amount the volume jumps depends on the initial settings:
 off%  on%
  0      0
  1     56
 20     75
 40     95
 60    115
 80    136
100    155
So it seems to always jump by 55 percent points, except when starting at zero.
5. The jump doesn't always happen. It seems you can influence it by turning 
down the sound source volume. It then doesn't reappear after another 
stop/start cycle. However, turning it back up also doesn't make it reappear, 
so I'm kind of at a loss how to reproduce this again....
6. At a volume of 0% in 'pavucontrol', no sound is heard. Up to 43%, I'm 
getting static. At 44%, the sound is completely mute, above it, the music 
rises in volume without any static. Something is odd here...

I have also encountered the sound volume jumping down now and then, but I 
haven't found a rule there yet. In case you need further info, just drop me a 
note.

Uli