[PD] How to increase audio latency on linux?

Miller Puckette msp at ucsd.edu
Tue Dec 4 17:54:17 CET 2012


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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