[pulseaudio-discuss] Rhythmbox and Pulseaudio: per-application volume adjustment causes major ruckus

[Jud Craft]

Unlike most multimedia applications that have an internal volume
meter, Rhythmbox actually communicates it's internal volume value to
Pulseaudio, and Pulse in turn uses that as Rhythmbox's per-app volume.

Problem:  when Rhythmbox is the only app running, this means that any
Main Volume adjustment to PulseAudio is doubly applied to Rhythmbox
(since Pulse will adjust Rhythmbox to match the main system volume,
which changes Rhythmbox's internal volume setting).

So, for example, moving the Main Volume to 88%, will cascade back into
Rhythmbox, reducing the in-app volume by over 50%.

Note that like with alsamixer, Pulseaudio's per-app audio doesn't
actually match Rhythmbox's internal volume.  Hence, setting the Pulse
volume for Rhythmbox to 88% will set the in-Rhythmbox volume to near
45%.

This is a rather unfortunate side-effect, since it means that
adjusting volume while playing music with this program is a major pain
in the arse, and the only solution that causes no problems is to leave
it at max, which unfortunately is a little uncomfortable.  Any change
to Rhythmbox's in-app volume or PulseAudio's per-app volume will
bubble to the other in unpredictable ways.

One clear solution would be for Rhythmbox to stop advertising its
internal volume to PulseAudio.  Another would be if Pulse didn't
adjust Rhythmbox's audio when it's the only program present.

By the way, if you run one audio program, and reduce Main Volume to
80% (and thus Pulse moves the program down to 80% too), does that
result in a total .8 x .8 = .64 total volume adjustment overall?