smithi at nimnet.asn.au
Sat May 18 07:22:44 UTC 2013
On Fri, 17 May 2013 08:04:14 -0700, Sean Bruno wrote:
> I'm working on a port of IDJC, which requires jackd.
> At this point, I'm stuck on two jackd related issues.
> 1. How do I configure freebsd+jackd for realtime audio? Currently I
> have to configure my .jackdrc to disable realtime audio, e.g.
> /usr/local/bin/jackd -r -T -d oss
Just wondering what problems are evident running it without rtprio? I
gather -r with no value gives 48000, how many consumers? Just that even
on an old 2GHz P4 on debian 4, we found no real issues running without
-R that tuning buffer sizes etc wouldn't fix; FM pre-transmitter feeding
an audio logging task (darkice to mp3 VBR -q0 @ ~210kbps) and our stream
feed (patched edcast_jack to mp3 VBR -q2 @ ~192kbps) ALSA, though.
That said, we wound up using -R anyway (both consumers running as root)
but it made no noticeable difference with that load: /etc/default/jackd
OPTIONS="-R -m -d alsa -d hw:0 -C hw:0 -r 44100 -n 3 -p 4096"
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
16483 root 15 0 41252 3456 1580 S 8.2 0.7 173:15.30 edcast_jack
3032 root 15 0 25752 3576 1940 S 7.4 0.7 2583:03 darklogger
3002 root 22 0 37740 3612 3312 S 0.2 0.7 44:29.66 jackd
1491 root 25 10 2232 1140 864 R 0.2 0.2 0:00.96 top
Re what Diane said, that seems also to be the case on linux, though I
know nothing about our jackd port or what can be done here on FreeBSD.
Use realtime scheduling. This is needed for reliable
low-latency performance. On most systems, it
requires jackd to run with special scheduler and memory
allocation privileges, which may be obtained in
several ways. The simplest, and least-secure method is to
run jackd with root privileges. This means
that all JACK clients must also run as root. With a Linux
2.6 kernel, ordinary users can run jackd and
its clients using options of the realtime LSM. Linux 2.4
kernels need "POSIX draft capabilities"
enabled (see the <linux/capability.h> include file).
Using that method, ordinary users who invoke the
daemon using jackstart, can later launch JACK
clients without running them as root. See
http://jackit.sourceforge.net/docs/faq.php#a52 for more
> 2. Any clues on getting the microphone working with jackd? My
> microphones work fine under audacity, but I don't seem to be able to get
> any audio from microphones.
No idea sorry, and while interested, sadly no time to play with these:
404. http://people.freebsd.org/~sbruno/shout-idjc/ works :)
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