[LAD] Is there a Linux Software Mixer?

Paul Davis paul at linuxaudiosystems.com
Tue Nov 30 13:52:50 UTC 2010

On Tue, Nov 30, 2010 at 1:37 AM, Rory Filer <rflyer at gmail.com> wrote:

> dmix plugin,
> Nama overtop of Ecasound
> jackeq
> Now it's a question of sorting through these and seeing which one(s)
> will work on my
> platform. I'll also need to figure out how separate applications can
> open the same
> audio device - but that might become clear when I understand how these
> mixers fit
> into the system.

I think you've walked away with slightly the wrong message here.

There are two approaches to the situation of multiple applications
using one soundcard.

One involves using the capabilities built into ALSA itself. This means
making each application open a dmix device. Rather than telling them
to open "default" or "hw:0" or "front", you would tell the
applications to open, most likely, dmix:0

The other involves using a user-space server. The only two servers
worth considering are PulseAudio or JACK and they are quite different.
PulseAudio can be used even though the applications using it believe
that they are just using a regular ALSA device. This is way that quite
a lot of distros set up PulseAudio these days. By contrast JACK
generally requires that applications are written to use JACK. This may
not require that the application itself is written to use JACK - the
support for JACK might come from some intermediate audio API such as
gstreamer. There are ways to route most things via JACK (even regular
ALSA-using apps) - details can be found in the JACK FAQ at
http://jackaudio.org/faq where you can also find a brief explanation
of the differences between PulseAudio and JACK.

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