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saxindustries

Member

Registered: 2011-04-04

Posts: 4

JACK, PulseAudio, RealTime

Maybe this isn't possible, but I'm wondering if it is:

Right now, I have JACK running with real-time scheduling enabled.  I'm able to start it up, connect clients, etc, without any issues.

I'm trying to run PulseAudio and have it connect as a JACK client, and if possible, I'd like it to run with realtime priority as well.

Whenever I start PulseAudio, everything seems to connect fine, but I get the following messages:

[john@slim ~]$ pulseaudio 
W: module-jack-source.c: JACK error >Cannot use real-time scheduling (RR/5)(1: Operation not permitted)<
W: module-jack-source.c: JACK error >JackClient::AcquireSelfRealTime error<
W: module-jack-sink.c: JACK error >Cannot use real-time scheduling (RR/5)(1: Operation not permitted)<
W: module-jack-sink.c: JACK error >JackClient::AcquireSelfRealTime error<

Like I said, maybe it's not necessary - the only application I use that regularly uses PulseAudio is Skype.  I believe it should have realtime priority, as I want my webcam + sound to remain in sync at all times.

Right now, I just shutdown the JACK server and fire up PulseAudio with the default config, and everything seems to work fine.

Has anybody achieved this before, is it possible, and is it necessary?

I'm using the default daemon.conf file, the only change being that I explicitly set daemonize=no.

Here's my ~/.pulse/default.pa file: - I'm only loading the JACK modules for now.

#!/usr/bin/pulseaudio -nF
#
load-module module-jack-source
load-module module-jack-sink

Also, the relevant section of /etc/security/limits.conf:

@audio          -       rtprio          80
@audio          -       memlock         3042873

I'm running jack2 1.9.7-1 and pulseaudio 0.9.22-2

Any help is much appreciated, thank you.

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,356

Re: JACK, PulseAudio, RealTime

Why should skype not having realtime priority affect syncing of webcam/sound? Syncing isn't really affected by realtime priority unless you're simultaneously running some hog of an app, and even then the software should really be doing its own compensation.

Realtime is for apps which really need regular information exactly on time. Skype does not fall into that category, its already running over a high-latency internet...

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saxindustries

Member

Registered: 2011-04-04

Posts: 4

Re: JACK, PulseAudio, RealTime

That sounds like it's about right.  The default Pulse setup is to be realtime, but I guess running non-rt pulse on top of JACK is fine, too.