[Jack-Devel] Multiple latency across jack

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

[Jack-Devel] Multiple latency across jack

liebrecht
Is it possible to have different signal sources handled differently by
jack ?

As an example, Mixbus uses jack directly  and runs at 44100 buffer 128/2

I have other applications running under emulator that needs deeper
buffers and longer latency is not an issue.
These other applications all use pulseaudio and I dont know if
pulseaudio causes the overruns and resultant rickety sound.

I am really not familiar how pulseaudio works with jack. At the moment
both pulseaudio and mixbus/jack outputs
sound simultaneously  to the same output device without problem

At the moment I cannot find a way to increase the latency for all other
sources than Mixbus. The other sources needs larger buffers not to work
intermittently as it is now seemingly forced to use the same buffer size
as mixbus which works flawless at 128.

How should I go about it to run different sources at different buffer
settings ?
This is a bit above what I could find online in the Faq.

Or should I find a way to send all these applications directly to jack
for better buffer handling and somehow cut out pulseaudio ??
_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
Reply | Threaded
Open this post in threaded view
|

Re: Multiple latency across jack

Chris Caudle
On Thu, December 27, 2018 10:05 pm, [hidden email] wrote:
> Is it possible to have different signal sources handled differently by
> jack ?

All jack clients run at the same buffer size.
I think you could make a client which stored multiple buffers and handled
the appropriate translation between buffer sizes, but I am not aware if
Pulse does this.  The pulse jack implementation has in the past been
described as not optimal.

> As an example, Mixbus uses jack directly  and runs at 44100 buffer 128/2

Do you need such low latency for Mixbus?  Increasing the latency would be
the simplest thing to check if you are having problems with under-runs.

> These other applications all use pulseaudio and I dont know if
> pulseaudio causes the overruns and resultant rickety sound.

Check the default sample rate which pulseaudio uses, and the sample rate
of the applications which connect through pulse.  PulseAudio will use
sample rate conversion when clients and default sample rate do not match,
that causes higher CPU usage and decrease in audio quality.

> I am really not familiar how pulseaudio works with jack. At the moment
> both pulseaudio and mixbus/jack outputs
> sound simultaneously  to the same output device without problem

The jack server requires exclusive use of an output device, so you must be
using the jack-sink client of pulse audio to send the audio to jack for
output to the physical device.

> Or should I find a way to send all these applications directly to jack
> for better buffer handling and somehow cut out pulseaudio ??

That would be the optimal solution.

--
Chris Caudle


_______________________________________________
Jack-Devel mailing list
[hidden email]
http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org