There are some gems in the linux-audio-dev archive. I'll post relevant snippets below as fancy strikes me.
Low latency [device] sharing isn't of much value by itself if the data
from different sources is not in sync. The data can only be in sync with
a model that:
1) periodically waits idly for every process using the daemon to
have the correct amount of data - this will lead to
dropouts at low latency settings.
OR
2) periodically and actively tells each process using the daemon
that its time to produce (or consume) a the correct amount
of data.
If you or anyone else knows another way, please tell me, Steinberg,
MOTU, Digidesign, Apple, Propellerheads, and Emagic about it.
I also say again, and this REALLY IMPORTANT for people to understand
and know: ALSA *already* has a sound server daemon, 1 per
declared-and-used PCM "shared" device. ALSA apps need do *nothing*
except be correctly written to use the daemon - there is no difference
in using it to using a PCM "hw" device or any other kind of ALSA
device.
The problem is that most people are running OSS-API apps, and getting
those apps to use a "shared" PCM device is, while not particularly
complex, not what you'd call "trivial" (it requires an LD_PRELOAD
"hack").
-- paul davis, 13 dec 2001
For the jackit-devel web archives: http://www.eca.cx/lad/2001/Nov/0234.html - Thread "Simple question on JACK and callbacks" ... few interesting messages about jack_rechain_graph() and the way jackd optimizes subchains. -- kai vehmanen, 16 dec 2001