[pulseaudio-discuss] Controlling pulseaudio volume with kmix

[Lennart Poettering]

On Sat, 30.05.09 12:03, Piero Filippin (filippinp at yahoo.co.uk) wrote:

> Hi,
> first of all I want to thank everyone for their work on pulseaudio. I  
> always thought Linux audio sucked, finally something which make sense  
> (and works)!
> I enabled the a52 in asound.conf, and finally I can enjoy surround sound!
>
> However, I am having 2 issues. First of all, for some reasons I cannot  
> understand, I cannot use the a52 output on pavucontrol, the sound is  
> "choppy", this means something like 100ms of audio every second - but  
> "simultaneous output on a52" works like a charm. Just a weirdness.

This is probably an issue with the timing logic in the a52 ALSA
backend. pavucontrol sets rather short latency settings on all devices
to be able to show the PCM monitoring meters that closely reflect what
you actually hear. These lower latency settings probably break the a52
backend.

Please note that Fedora does not ship that module due to patent
issues, and hence I have never tested if it actually works. I wrote
the a52 logic in PA without ever having tested it.

It would probably be a good idea to include the a52 logic directly in
the PA plugin to fix all the timing issues, instead of relying on ALSA
for that. But uh, given the broken patent situation this is unlikely
to happen anytime soon. Sorry.

> The only serious issue: I am not able to do is to change the volume with  
> kde4 kmix (I was able to before enabling a52). I can change the volume  
> on every single application (eg volume slider in amarok2 or mplayer) or  
> using pavucontrol, but changing the volume in kmix has no effect (only  
> the master mute works, and it was not working before).

On KDE ymmv. Try using the newest g-v-c. Please note that legacy
mixers like kmix tend to expose the full low-level analog alsa mixer. If you
use digital output that is useless, use the PA volumer control
instead, either in the form of pavucontrol or at a lower level with
pacmd/pactl.

Lennart

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