26 Oct
2009
26 Oct
'09
4:06 p.m.
OK, perhaps a stupid question: does jackd mix? In other words, let's
say we have two or more audio applications outputting to Jack; will Jack
mix the streams? Or does it send them each independently to the sound
driver?
J.E.B.
26 Oct
26 Oct
4:10 p.m.
A guess of mine, yet built on some logic: It mixes the streams, before sending
them to one port.
Why? If it would send unmixed streams to ALSA, ALSA would need to mix them,
which it doesn't do automatically. I'm not sure about OSS's and freebob's
and
the other backend's features.
Why else? JACK also sends (possibly multiple) streams not only to the
soundcard but to other applications. If JACK wouldn't mix them, then your
applicationmust have special code to deal with it.
Kindest regards
Julien
--------
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4:20 p.m.
New subject: Q: does jackd mix?
On Mon, Oct 26, 2009 at 2:07 PM, Jonathan E. Brickman
<jeb(a)joshuacorps.org> wrote:
OK, perhaps a stupid question: does jackd mix? In
other words, let's
say we have two or more audio applications outputting to Jack; will Jack
mix the streams? Or does it send them each independently to the sound
driver?
Well, yes. The mixing is done on a port-by-port basis. Whenever
there is more than one input connected to a JACK port the
corresponding samples are added together.
This can produce float values greater than 1.0, which will overflow
when routed to a physical output device. But, there are many JACK
applications that allow you to adjust output levels.
--
joq
4:22 p.m.
New subject: Q: does jackd mix?
2009/10/27 Jonathan E. Brickman <jeb(a)joshuacorps.org>
OK, perhaps a stupid question: does jackd mix? In
other words, let's
say we have two or more audio applications outputting to Jack; will Jack
mix the streams? Or does it send them each independently to the sound
driver?
J.E.B.
Connect mplayer and maybe ardour to system outs and play. You have mixing in
action right there.
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4 comments
4 participants
participants (4)
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Jack O'Quin -
Jonathan E. Brickman -
Julien Claassen -
Ray Rashif