ALSA mixer query

ALSA mixer query

[Irfan Shaikh]

Hello all,

             I am rendering audio to a PCM playback device (hw:0,0). I also need to render the same audio data to second PCM playback device (hw:0,1).

1) Can i use ALSA mixer APIs so that i give PCM audio data to 1 playback device or some common interface,
    but the PCM audio data is rendered to both devices (hw:0,0 and hw:0,1)

Regards
Irfan

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Re: ALSA mixer query

[Clemens Ladisch]

Irfan Shaikh wrote:
> I am rendering audio to a PCM playback device (hw:0,0). I also need
> to render the same audio data to second PCM playback device (hw:0,1).
> 
> 1) Can i use ALSA mixer APIs so that i give PCM audio data to 1
>    playback device or some common interface, but the PCM audio data
>    is rendered to both devices (hw:0,0 and hw:0,1)

The mixer API ist just an interface to the hardware, so this would
depend on the hardware's capabilities.

However, you could use the plugin mechanism to create a virtual PCM
device that routes its data to two actual devices.  See
<http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html#pcm_plugins_multi>.

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Regards,
Clemens