[LAD] Merging alsa subdevices into multichannel

Jens M Andreasen jens.andreasen at comhem.se
Wed Nov 19 17:18:37 UTC 2008

[continued from previous post]

On Wed, 2008-11-19 at 05:45 +0100, Jens M Andreasen wrote:

> Hmm ... I could try and open the three raw devices from the same app and
> see how that will work out, if they perhaps are drifting? 
> Tomorrow!  :)
> /j

.. which I have done now:

a) One program 'capture' opens two devices ("hw:0,0,0" and "hw:0,0,1")
and merges them into a single stereo image which is piped out on stdout.

b) another program 'playback' opens a third device ("hw:0,0") for output
and reads a stereo image from the pipe on stdin

used as: ./capture|./playback 
.. and works without flaws

What does NOT work - and what might be a hint to what is wrong - is
starting jackd as either playback- or capture only (with -P or -C). Only
the duplex mode -D is running stable.

I don't get this? :-/
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