[alsa-devel] How to choose output channels for AD1386A sound?

Takashi Iwai tiwai at suse.de
Thu Apr 17 13:57:36 CEST 2008

At Thu, 17 Apr 2008 10:27:59 +0000,
Ihar Hrachyshka wrote:
> Hello!
> I build my BF533-EZKIT-based board (Blackfin processor development
> board) sound system on AD1386A sound. I use blackfin.uclinux.org
> distribution for it. One of my board's function is to play three
> different stereo sound streams simultaneously on it. What I done is
> choosing for AD1386 '3 stereos' option. After loading the kernel, my
> software is able to open pcm 3 times and plays sound properly, with no
> glitches or smth. The only missed functionality is that I can't
> specify the needed subdevice I want to play a stream on. I should have
> the possibility to play, f.e., mplayer stream on the 3rd stereo output
> while the 1st and the 2nd are not used. How can I do it?

You can pass three numbers to PCM arguments: card, device and
subdevice.  For example, the below will choose card = 0, device = 2,
subdevice = 1, i.e. the secondary substream:
	% aplay -Dplughw:0,2,1

> Also that would be great if I can optionally play the same stream on
> all the outputs.

You'll need to define a PCM with multi plugin.


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