Re: Build-in mixer

[Paul Davis <paul@linuxaudiosystems.com>]

>I don't know, if the term "mixer" is used correctly, because i am not 
>expert on it. I have in mind to use ALSA by more than one programs at 
>the same time (simultaneously), and ALSA itself should mix these audio 
>streams to one and play it via soundcard.

just so you know, although this functionality is certain desired by
many, its not the way that some users want things to work. as a
result, ALSA makes this possible, but it doesn't do it by default. Put
another way, it provides a mechanism to do this, but doesn't enforce
it as a policy.

>I tried dmix plug-in together with aplay -Dplug:dmix simultaneously from 
>  two consoles and it works sufficiently (well, "underun!!! (at least 
>...ms long)" message was there but i don't know, if is is serious bug or 
>not). I thing that it should work transparently without special swithes 
>or settings separately for each application or its instance, but i don't 
>know if it is possible or not.

the dmix plugin is indeed the way to do this. what you need to do (or
perhaps ALSA needs to by default) is to set up your ~/.asoundrc so
that the default device is a dmix configuration.

all ALSA applications should accept options from the user specifying
which PCM (or MIDI or ...) device they should open, and they fall back
to "default" if none is specified. consequently, with this
configuration setup, you'd get what you are hoping for, but other
people could still use "hw:1" or specific named devices when they
don't want dmix to get in the way (e.g. professional audio users).

unfortunately, i don't know how to write an ~/.asoundrc file that
would do that :( somebody will, though.

--p


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