[PD] readsf~ and latency problems

Michael Edwards michael at ccrma.stanford.edu
Tue Jul 3 00:30:06 CEST 2001

Hello all,

I'm new to PD and this graphical programming thing but managed to get
things installed on my Red Hat 7.0.1J (Kernel 2.2.16-22) Linux machine. 
First something to that point: I too, as the documentation mentions, had
problems with "libtcl.so" and "libtk.so"  The proffered solution (ln -s
libtk8.3.so libtk.so etc.) did not work however because pd
(pd-033PATCH1) was looking specifically for libt*8.0.  Installing the
rpm instead of compiling the .tar.gz distribution solved the problem

Anyway, that wasn't my main point.  I'm having (only!) two problems at
the moment.  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?

The second problem is with sfplay~ and its open message.  When I 'open'
a longish file (that every other sound player seems to like well enough)
without setting the optional header size etc. and then try to play it
with 'sfplay~ 2 1000', I get no output.  When, however I give arguments
like "open 0 40 2 2 l" it plays ok, but of course skipping some samples
and creating a click.  Do I really have to work out how big my header is
etc. to get this object to work?  Any hints out there?

Apologies in advance for the verbosity and perhaps arcane English of
this mail.  All the best,



   Michael Edwards                Tel:    Office: +43 (0)662 6198-5125
   Universitaet Mozarteum                   Home: +43 (0)662 844462
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   A-5020 Salzburg              Email:    mailto:m at michael-edwards.org
   Austria                        Web:    http://www.michael-edwards.org

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