[PlanetCCRMA] jack - howto?

Fernando Pablo Lopez-Lezcano nando@ccrma.Stanford.EDU
Wed Apr 9 13:08:01 2003

> After looking into it a bit more, I realized that jack does not automatically
> connect its inputs and outputs to the jack server unless explicitly
> told to (using the -i and -o command line options). Now that I do, I
> can see by looking at the jackd verbose output that it now is making
> the (apparently) appropriate connections, although I still don't get
> any sound out of it.

That does not sound correct. The jack _server_ (jackd) creates ports for
all available alsa inputs and outputs. You do not have to specify any
command line options for that. This should be enough in most cases:
  jackstart -R -d alsa -d hw

The jack _clients_ (ie: programs that use the jack server) are all
different. Some connect their inputs and outputs to jack automatically,
some do not and then you have to use qjackconnect or alsa-patch-bay
--jack to connect them. Or the command line utilities...

> I have my alsa mixer settings set to record mic in - I can do 'arecord'
> from the command line and the input gets recorded, so that's not the
> problem. I can run alsaplayer with the jack output option, and I see
> it make the connection to jackd, and I can hear it playing, so jack
> output would seem to be working. I played around with the
> enable/disable button in jack

??? There are no buttons in "jack", I have no idea what you mean by
that. Jack itself does not have a gui. 

> but still I hear nothing come out of it.

A simple test. Start "freqtweak" (after starting jackd), it connects
inputs and outputs automatically. See if you see something in the input
spectrogram when you say something into the mic. 

-- Fernando