[linux-audio-dev] I need help! I can't handle the problem about full-duplex (playback & record) programming

Paul Davis paul at linuxaudiosystems.com
Mon Dec 16 08:14:00 UTC 2002


>> You may want to look into ALSA (http://www.alsa-project.org) which is
>> the new Linux sound architecture. Also, it would probably be good to
>> make sure your audio card is actually capable of full duplex and that
>> this feature really does work in Linux (with the drivers you decide to
>> code for). I can't think of any quick and easy programs to test full
>> duplex (anyone else have any ideas?). Good luck.
>
>I think what you could do in ALSA is to make a "loopback" connection
>from your soundcard's Line Out back into its Line In, then playback some
>.wav or .mp3 with e.g. aplay and simultaneously (try to) use arecord(*)
>to record whatever comes back in on Line In. 

this isn't full duplex. its two independent processes using one
direction, which doesn't actually test the driver in the same way as a
single process.

JACK (jackd) runs full duplex by default, and so could be considered a
test app.

--p



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