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Crash when launching alsa_in or alsa_out from within Qjackctl


With the help of some knowledgeable people at ubutuforums, I have recently discovered alsa_in and alsa_out which come with versions of jackd 0.116 and up (but not Jack2, as the functionality is covered differently) and allow the addition of a second device that jack can utilize. I am using it to add a usb mic in addition to my onboard soundcard. I'm using Debian Squeeze packages of jack and Qjackctl. When I put the alsa_in command (i.e., alsa_in -d hw:1)in the "Execute script on Startup" or "Execute script after Startup", Qjackctl freezes when I start jack. If I kill Qjackctl and restart it, it shows jack is running and opening connections shows the usb mic, so the script is clearly being executed. If I just launch Jack normally with Qjackctl and execute alsa_in from the command line, all is fine.

This has been confirmed by at least one other person at Ubuntuforums using a different distribution and package versions than me.

rncbc's picture

So it's a freeze, not a crash.

Are you sure you aren't missing an ampersand (&) at the end of the alsa_in or alsa_out command lines ?

You need that for any of those commands to run in the background, otherwise QjackCtl just gets stuck indefinitely while waiting for the scripts to terminate. And it might just look that it freezes, because neither alsa_in nor alsa_out does immediately exit() if started successfully ;)

Check that out.

I'm guessing that that is the problem - I didn't use an ampersand. I'll confirm after work today.

hi guys,

I am the other guy who confirmed the behavior. I did test it with the & when I saw the freeze.
It did not work, the alsa_in/out client does not show up in the graph. It's like it started and stopped immediately.

But I reinstalled jack1 right now and retried (I use jack2 most of the time) for the sake of my reply here. And it worked.
So I guess it blew on me in my 1st attempt :lol:


That was the problem. Works now. Thanks!

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