On 07/18/2010 09:46 PM, Andrew Bryant wrote:
If I use qjackctl to start jackd, the connect window
shows two capture
ports and two playback ports.
I can then start a pair of meterbridge dpms, and connect their inputs
to the capture ports. Signal applied to the mic jack then shows up on
the meters. So I deduce that the capture ports are related in some
way to the mic jack.
They are capturing whatever is being sent to the internal digital input
of the device. So anything you have enabled in the mixer settings [line
in, mic, cd] will be heard in jack.
If I connect between the capture ports and the
playback ports, should
I then expect the signal to be present at either the headphone or the
line output jack?
Yes, if you have unmuted the master output and turned up the pcm
channel. Some cards also have additional input controls that need to be
tweaked.
And (this may actually be the same question), the
soundcard has
numerous analogue inputs (mic, line, CD), at least two outputs, not to
mention whatever the mechanism in the digital domain is to relay
internet radio etc. Can they all appear as ports in the qjackctl
connect window? Is there some special imprecation needed when I start
jackd?
This is dependant on the card. If it is a multichannel device then you
may see multiple inputs but for most(all) consumer cards the inputs are
mixed at hardware level and presented as one (stereo) to jack.
--
Patrick Shirkey
Boost Hardware Ltd