[linux-audio-user] Assistance with splitting up stereo channels in ALSA is appreciated.

Jack O'Quin joq at io.com
Mon Apr 26 12:16:57 EDT 2004

Malcolm Baldridge <linux-audio at paypc.com> writes:

> This brings me to my question.  It turns out that I should be sending a
> "beep" down the lines I am monitoring to notify the parties that they are
> being recorded.  I have a spare output channel [the R channel of the main
> PCM device].  The L channel is providing music-on-hold, remember, via mpg123
> which is using the ALSA driver.  
> How can I configure ALSA (via asoundrc?) to split the PCM device into two
> independently accessible components for the L and R channels?  I'm very
> pleased with mpg123 and do not feel I need to reinvent any wheels on that
> side.  I don't feel it necessary to give Jack more to do, so I'd like to
> stay out of Jack if possible.  (I run jackd with "jackd -R -d alsa -S -C -p
> 4096 -M -n 2 -r 11025").

Don't know about ALSA, but sending beeps through JACK should be
trivial.  You could probably hack the jack_metro example client to do
that in just a few minutes.

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