18 Feb
2008
18 Feb
'08
8:48 a.m.
Quoting Arda Eden <ardaeden(a)gmail.com>om>:
While Jackd is runnning, other applications like
Amarok and system sound
alerts cannot use Alsa at the same time.
But JACK diagram given in it's web site shows that any non-jackified
application can use Alsa Userspace Library at the same time.
And, Sampo Savolainan told me that, other programs can use the ALSA
library,
but jack needs exclusive
access to the audio hardware it uses. Nothing is stopping a non-jack
program
to access other sound interfaces you might have in your system.
How is this exclusive access given to Jack ?
Exclusive access is not given to it. Jack takes exclusive access when you
start it. If it's unable to get exclusive access it will fail to start.
Once it has started, other programs will be unable to access that audio
device. The device is released when jack stops.
Sampo
Sampo
18 Feb
18 Feb
9:21 a.m.
New subject: Jackd and Other Alsa applications at the same time.
On Mon, Feb 18, 2008 at 02:48:35PM +0200, Sampo Savolainen wrote:
There is nothing in jack's alsa backend code that tries to get
exclusive acces. The simple fact is that ALSA pcm devices are
always exclusive. The only exceptions being the dmix/dsnoop devices
which usually don't work very well with jack.
How is this
exclusive access given to Jack ?
Exclusive access is not given to it. Jack takes exclusive access when you
start it. If it's unable to get exclusive access it will fail to start. Once it has started, other programs will be unable to
access that audio
device. The device is released when jack stops.
Correct.
--
FA
Laboratorio di Acustica ed Elettroacustica
Parma, Italia
Lascia la spina, cogli la rosa.
2:30 p.m.
New subject: Jackd and Other Alsa applications at the same time.
On Monday 18 February 2008, Sampo Savolainen wrote:
Quoting Arda Eden <ardaeden(a)gmail.com>om>:
I guess one should mention subsubdevices here. Soundcards like emu10k1 or
cs46xx offer several subsubdevices per subdevice (e.g. 32 in case of cs46xx).
So if an app opens a subdevice like hw:0,0, it implicitly opens a
subsubdevice. If a soundcard driver offers only a single subsubdevice, then
the subdevice cannot be opened anymore.
Some people also use the term hardware mixing for this, though there's some
possible confusion with the mixer device used to control volumes.
So in a nutshell: On some cards, the alsa driver allows opening the hw device
roe than once. Only few select devices offer this though..
Flo
--
Palimm Palimm!
http://tapas.affenbande.org
While Jackd is runnning, other applications like
Amarok and system sound
alerts cannot use Alsa at the same time.
But JACK diagram given in it's web site shows that any non-jackified
application can use Alsa Userspace Library at the same time.
And, Sampo Savolainan told me that, other programs can use the ALSA
library,
but jack needs exclusive
access to the audio hardware it uses. Nothing is stopping a non-jack
program
to access other sound interfaces you might have in your system.
How is this exclusive access given to Jack ?
Exclusive access is not given to it. Jack takes exclusive access when you
start it. If it's unable to get exclusive access it will fail to start.
Once it has started, other programs will be unable to access that audio
device. The device is released when jack stops.
6347
days inactive
6347
days old
linux-audio-user@lists.linuxaudio.org
2 comments
3 participants
participants (3)
-
Florian Schmidt -
Fons Adriaensen -
Sampo Savolainen