[PD] readsf~ and latency problems

Nick Fells nick at music.gla.ac.uk
Tue Jul 3 11:26:41 CEST 2001


Michael Edwards wrote:
> The first is with latency.  I see in the docs talk about
> 8ms, 5ms, 3ms latency and how you can improve these lamentable figures
> (?!).  At the moment I'm looking at about 1000ms latency when playing
> sound files :-(  I'm using the OSS drivers and don't really have much
> choice about that because I made the mistake of buying a turtle beach
> multisound pinnacle card a few years ago.  This card has never been well
> supported and it was only with extremely high curse factor that I got
> the bugger playing at all under Linux, but I can assure you now that
> there doesn't appear to be any latency when, for example, I press the
> play button on 'snd' from CCRMA.  When I trigger a sound in PD with the
> mouse or keyboard however, I get about a 1 second time lag before the
> sound starts.  And this no matter what combination of -audiobuf
> -fragsize -blocksize I care to use.  Any ideas anyone?


Michael,

I too fought with this card for a while. Don't know if this is the root
of your problem...

Don't know if you have the driver files. If not, go to Andrew Veliath's
site at http://atv.ne.mediaone.net/linux-multisound/

and download the driver source archive. In there is basically a 'readme'
called MultiSound, which describes options you can pass to the kernel
module (it is better, I think, to load the soundcard driver as a module
using 'insmod' rather than hard-coding it into the kernel for this very
reason). One option you can set is 'fifosize', the Pinnacle's firmware
buffer size. By default I seem to remember it's set to something really
high, but you can reduce it by specifying when you do 'insmod' (I'd
advise you read the MultiSound file carefully).

In my machine I just set up a script to do the necessary insmod etc at
startup.

Hope that helps.

Nick


-- 
Dr Nick Fells,	
Music Department,
University of Glasgow,		Tel: +44 (0) 141-330 4096
Glasgow G12 8QQ			Fax: +44 (0) 141-330 3518
UK.				http://www.music.gla.ac.uk/~nick



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