[PD] ASIO latency (windows)

Miller Puckette mpuckett at man104-1.ucsd.edu
Sun Nov 28 00:18:59 CET 2004

Well, the pd code, unless I've written it wrong somehow, sets the
total portaudio buffer size roughly to the requested latency in samples.
Also, having Pd poll a fifo that's filled in by the callback routine should
only add another 64 samples of latency, plus whatever the OS wakeup latency
is.  Certainly this shouldn't be more than 20 msec or so on a reasonably modern
system.  So I don't know how the latency is getting up to 70!

Anyway, I'm planning to upgrade to Portaudio 0.19 on all platforms for 
PD version 39... I'm playing it conservatively for 0.38 because I've almost
got it all working and don't want to break things now.


On Mon, Nov 22, 2004 at 11:53:42PM +0100, gnter geiger wrote:
> On Mon, 22 Nov 2004, smoerk wrote:
> > > Seems that the portaudio code of pd is less than optimal. Not sure if
> > > the way to solve this is writing native ASIO code, as it is done currently
> > > by Tim and Tom (;)), or to fix the portaudio stuff.
> > >
> > > Guenter
> >
> > but it works perfectly with audiomulch. it seems it's not a problem of
> > portaudio (afaik ross bencina wrote portaudio and audiomulch), but the
> > combination of portaudio and pd.
> Thats what I meant with "the portaudio code of pd". Its the way pd uses
> portaudio that is wrong. First, I think it uses the maximum number of
> buffers. Then, the pablio (portaudio blocking I/O) thing is a bad hack,
> as portaudio is meant to be used in a callback model.
> Guenter
> PS: I have been talking with Ross about this and he sort of agrees, he
> is sitting in my office.
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