Multiple sound support in Alsa, is it possible?

English Multimedia
#1

Okay to solve my pepper flash issue in openSUSE i turned off pulseaudio and am now using Alsa.
However alsa has a big limitation, it can only work one sound app at a time.
And I am the kind of person who browses the web listening to music and some sites use flash and sometimes take the sound away,
This is where pulseaudio was better and why so many are using it as it supports multiple sound apps.
But alsa not so much.
I did try to update alsa via https://en.opensuse.org/SDB:Alsa-update and while my transition to the newer alsa went fine alsa still doesnt support multiple sound outputs.
is there a way to make alsa work with more then one sound app, or am I stuck to the way it was back in 2005 when I first started using linux?

#2

Pulse is the software making all that possible. Installing pavucontrol allows you to play around with the settings. I already wrote in some other thread, that I met funny sound issues in Chromium caused by a laptop’s mic. I usually get around sound issues by fiddling with pavucontrol. This helped me to get Skype working for example.
These days most videocards have HDMI output, this often plays it’s role as well.
The best thing to do, is to run the mmcheck script.

#3

But Alsa also supports simultaneous output from several applications since years (through the dmix plugin).

Works just fine here, and I didn’t set up anything manually.

#4

??

This is incorrect for a lot of sound devices.

There are two ways that I know of to share audio devices in GNU/Linux:

  • with the alsa api => select the alsa API in most multimedia applications. ALSA, in addition to being the sound driver, also comes with an API that can be used by applications if so desired. For some (not all) hardware the alsa API will allow the audio device to be shared, even if a multimedia application has not let go of the audio device (via the alsa API). In the pre-pulse audio days, this used to mean for KDE users that they needed to select the xine backend in their desktop, and then go into xine (via the xine-ui application) and select the ALSA API in xine. But I do not know the state of this now wrt KDE.
  • use pulse audio to share the audio device => as noted already, by installing pavucontrol this becomes easy. A number of us have blogged on this subject.