[pulseaudio-discuss] Saving stream volumes per physical output

[Lennart Poettering]

On Tue, 05.01.10 19:37, Tanu Kaskinen (tanuk at iki.fi) wrote:

> 
> ti, 2010-01-05 kello 18:02 +0100, Lennart Poettering kirjoitti:
> > On Tue, 05.01.10 18:37, Tanu Kaskinen (tanuk at iki.fi) wrote:
> > > Consider this scenario:
> > > 
> > > Headphones' port volume is -10 dB. Speakers' port volume is also -10 dB.
> > > 
> > > I use headphones, and set the volume to -15 dB, because that is good.
> > > Then I switch to the speakers. The volume is now a bit too low, so I
> > > turn it up to -10 dB. Then I switch back to the headphones. m-s-r
> > > doesn't do anything, because it thinks one stream volume is good for any
> > > output. But the end result is that now the music is coming 5 dB louder
> > > to my ears than what I want.
> > > 
> > > Maybe you're going to argue that after switching to the speakers I
> > > should have changed the port volume instead of the stream volume. But if
> > > I know nothing about the flat volume logic, as would be the case for an
> > > ordinary user, it's much more likely that I'm just going to tweak the
> > > music player volume, which modifies the stream volume.
> > 
> > Na. I already agreed that m-d-r needs to be aware of ports and
> > save/restore volume based on the port that is actually selected
> > (i.e. remember what I wrote about using $SINKNAME@$PORTNAME). All i
> > was arguing abvoe was that m-s-r does not to be aware of ports.
> > 
> > m-d-r would then have to listen to port changes of a sink and
> > save/restore volume then. So the entire changes to m-d-r would be:
> > 
> > 1) always save two entries for each sink/source: $SINKNAME and
> > $SINKNAME@$PORTNAME. Always restore $SINKNAME@$PORTNAME if it is
> > available, fallback to $SINKNAME.
> > 
> > 2) also save/restore data when the port is changed for a sink: save
> > the settings for the old $SINKNAME@$SINKNAME@$PORTNAME and $SINKNAME,
> > then load the settins for the new $SINKNAME@$PORTNAME if that exists,
> > finally save it $SINKNAME again to store the new port.
> > 
> > The changes for that should be fairly easy to implement.
> 
> I fail to see how port volumes in m-d-r help in any way in my scenario.
> The sink/port reference volumes stay at -10 dB all the time so whatever
> m-d-r does, it isn't visible to the outside world. When switching back
> to the headphones, it's the job of m-s-r to restore the stream volume
> back to the -5 dB relative volume (actually I think that m-s-r should
> restore the absolute volume, but let's not go there yet).

I am not sure I follow. When you speak about "switching" to
headphones/speakers you do mean that you change the port of the sink,
right?

So you have one music stream playing at -10dB absolute on the
headphones. The ref volume on the sink is 0dB absolute. Now you switch
the port to the speakers. m-d-r should become active and set the new
ref volume for the sink to let's say -5 dB absolute. Since the stream
volume is stored relatively internally the resulting absolute stream
volume for your stream would be -15dB. Which is what is intended I
would say.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4