[PD] latency

Frank Barknecht fbar at footils.org
Mon Nov 17 01:29:58 CET 2003


Hallo,
guenter geiger hat gesagt: // guenter geiger wrote:

> On Sun, 16 Nov 2003, Frank Barknecht wrote:
> > I'm not sure, but as I see it, Pd does not use Portaudio in callback
> > mode, but the blocking in/out Pablio backend of PortAudio. IIR Pd
> > could stay with PortAudio, but could get much lower latencies by
> > converting the sound system to be callback based. This OTOH might
> > require large changes to Pd.
> 
> I'm not sure if changes would be really that big, the callback based
> implementation is quite easily doable (and has been done already),
> then there are some critical points that are in need of threading, like
> soundfile loading, patch opening, and the array drawing stuff (which
> in need of a redesign anyhow), gui communication.

Am I understanding this correctly: *If* Pd was converted to callbacks
*then* those things you pointed out would be in need of threading
(because they are not "realtime safe", as the Jack folks would put it)?

So using blocking IO (Pablio) lets us get away with doing those
non-realtime safe things kind of inside the dsp loop at the cost of
having large(r) latencies?

Just asking to get a clear view here...

ciao
-- 
 Frank Barknecht                               _ ______footils.org__




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