[PD] How to increase audio latency on linux?

[Roman Haefeli]

So the current state of affairs is that it is not easily possible on
linux? Is this in the responsibility of the application or the audio
back-end? I ask in order to find out whether this is the right list to
discuss the issue. 

It remains in the dark what the author of the ubuntugeek article meant
by "good", respectively "bad" sound quality. Is there any strong
indication that this will help in increasing the latency?

If my intent to have an as huge as possible latency in order to decrease
likeliness of drop-outs, it is still advised to use a low latency kernel
and run Pd/Jackd with realtime priorities? Or would I be better off then
with standard settings?

Roman
 

On Die, 2012-12-04 at 08:54 -0800, Miller Puckette wrote:
> Looks like the snd_pcm_hw_params_set_buffer_size_near(0 call in
> s_audio_alsa.c is truncating the buffer rudely (when I tried an advance
> of 10 seconds it went from 48000 to 43690 (one device) and 2048 (a different
> one).
> 
> I don't know any easy way around this... perhaps it's time to look at
> 'native' OSS in linux -
> 
> http://www.ubuntugeek.com/howto-install-oss4-in-ubuntu-10-04-lucid-for-better-sound-quality.html
> 
> cheers
> Miller
> 
> 
> On Tue, Dec 04, 2012 at 03:23:12PM +0100, Roman Haefeli wrote:
> > Hi all
> > 
> > For certain types (non-interactive) Pd patches, I'd like to be able to
> > set a large audio buffer, say 1s or more. However, I figured I'm not
> > able to do that on linux. 
> > 
> > With -alsa only the -blocksize parameter has any effect, but the maximum
> > allowed value is 2048 which still feels like only 200ms.
> > 
> > With -jack, neither the -audiobuf nor the -blocksize parameter have any
> > effect. It seems only the parameters applied to jackd have any effect on
> > the audio buffer, but non of the pd parameters (-audiobuf / -blocksize).
> > In jackd, the maximum I can have is 4096 frames/period and 2
> > periods/buffer which corresponds to 186ms @ 44.1kHz. Setting any higher
> > number for 'periods/buffer' results in the jackd server not staring. 
> > 
> > Recently, I figured that running Pd on Windows (7) with ASIO allows to
> > set virtually any -audiobuf value which allows to do tons of stuff in
> > zero logical time without risking a drop-out. I'd love to be able to do
> > that as well in linux. Is it possible? Or is this is an advantage of
> > Windows/Asio over Linux/Alsa?
> > 
> > Cheers
> > Roman
> >  
> > 
> > 
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